HEALTHEON CORP
424B4, 1999-02-12
COMPUTER PROCESSING & DATA PREPARATION
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<PAGE>
PROSPECTUS
 
                                5,000,000 SHARES
 
                                 [HEALTHEON LOGO]
 
                                  COMMON STOCK
 
                               -----------------
 
   HEALTHEON CORPORATION IS OFFERING SHARES OF ITS COMMON STOCK. THIS IS OUR
 INITIAL PUBLIC OFFERING AND NO PUBLIC MARKET CURRENTLY EXISTS FOR OUR SHARES.
  WE HAVE REQUESTED THAT THE UNDERWRITERS RESERVE UP TO 837,500 SHARES TO BE
        OFFERED TO THE PERSONS IDENTIFIED ON PAGE 76 OF THE PROSPECTUS.
 
                              -------------------
 
   OUR COMMON STOCK IS LISTED ON THE NASDAQ NATIONAL MARKET UNDER THE SYMBOL
                                    "HLTH."
 
                              -------------------
 
                 INVESTING IN THE COMMON STOCK INVOLVES RISKS.
                    SEE "RISK FACTORS" BEGINNING ON PAGE 5.
 
                               -----------------
 
                                PRICE $8 A SHARE
                               -----------------
 
<TABLE>
<CAPTION>
                                                               UNDERWRITING
                                                PRICE TO      DISCOUNTS AND     PROCEEDS TO
                                                 PUBLIC        COMMISSIONS        COMPANY
                                             ---------------  --------------  ---------------
<S>                                          <C>              <C>             <C>
PER SHARE..................................       $8.00            $.56            $7.44
TOTAL......................................  $    40,000,000  $    2,800,000  $    37,200,000
</TABLE>
 
THE SECURITIES AND EXCHANGE COMMISSION AND STATE SECURITIES REGULATORS HAVE NOT
APPROVED OR DISAPPROVED THESE SECURITIES, OR DETERMINED IF THIS PROSPECTUS IS
TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.
 
HEALTHEON HAS GRANTED THE UNDERWRITERS THE RIGHT TO PURCHASE UP TO AN ADDITIONAL
750,000 SHARES OF COMMON STOCK TO COVER OVER-ALLOTMENTS. MORGAN STANLEY & CO.
INCORPORATED EXPECTS TO DELIVER THE SHARES TO PURCHASERS ON FEBRUARY 17, 1999.
 
                              -------------------
 
MORGAN STANLEY DEAN WITTER                                  GOLDMAN, SACHS & CO.
 
HAMBRECHT & QUIST                                   VOLPE BROWN WHELAN & COMPANY
 
FEBRUARY 10, 1999
<PAGE>
    You should rely only on the information contained in this prospectus. We
have not authorized anyone to provide you with information different from that
contained in this prospectus. We are offering to sell, and seeking offers to
buy, shares of common stock only in jurisdictions where offers and sales are
permitted. The information contained in this prospectus is accurate only as of
the date of this prospectus, regardless of the time of delivery of the
prospectus or of any sale of the common stock.
 
                               TABLE OF CONTENTS
<TABLE>
<CAPTION>
                                                    PAGE
                                                 -----------
<S>                                              <C>
Prospectus Summary.............................           3
Risk Factors...................................           5
Use of Proceeds................................          15
Dividend Policy................................          15
Capitalization.................................          16
Dilution.......................................          17
Selected Consolidated Financial Data...........          18
Management's Discussion and Analysis of
  Financial Condition and Results of
  Operations...................................          20
Business.......................................          31
Management.....................................          46
 
<CAPTION>
                                                    PAGE
                                                 -----------
<S>                                              <C>
Certain Transactions...........................          59
Principal Stockholders.........................          64
Description of Capital Stock...................          66
Shares Eligible for Future Sale................          69
Certain United States Tax Consequences to
  Non-U.S. Holders of Common Stock.............          71
Underwriters...................................          74
Legal Matters..................................          77
Experts........................................          77
Where You Can Find More Information............          78
Index to Consolidated Financial Statements.....         F-1
</TABLE>
 
                              -------------------
 
    For investors outside the United States: Neither we nor any of the
underwriters have done anything that would permit this offering or possession or
distribution of this prospectus in any jurisdiction where action for that
purpose is required, other than in the United States. You are required to inform
yourselves about and to observe any restrictions relating to this offering and
the distribution of this prospectus.
 
                              -------------------
 
    Healtheon, Healtheon's logo, Virtual Healthcare Network, VHN, Healtheon
ProviderWorks and ProviderLink are some of our trademarks. SBCL SCAN is a
trademark of SmithKline Beecham Clinical Laboratories, Inc. Each other
trademark, trade name or service mark of any other company appearing in this
prospectus is the property of its holder.
 
                                       2
<PAGE>
                             DESCRIPTION OF ARTWORK
 
    At the top of the page there is a colored band with the Healtheon name and
logo on the left and the text "Pioneering the use of the Internet to simplify
workflows, decrease costs, and improve the quality of patient care throughout
the healthcare industry."
 
    On the middle left is the heading "Healtheon's Virtual Healthcare Networks"
over a cloud labeled "Internet" with the Healtheon logo superimposed. The cloud
has pictures of a telephone, a handheld computing device, a television with
internet access, and a computer monitor. The cloud is connected to four
photographs by lightning bolts. The upper left picture shows images from a
laboratory and has the heading "Suppliers" with the subheadings "Laboratories,
Pharmacies, Mail Order Drug and Pharmacy Benefit Managers." The upper right
picture is of doctors and has the heading "Providers" with the subheadings
"Physicians, Hospitals, Integrated Delivery Networks, Independent Practice
Associations and Practice Management Companies." The lower left picture shows
patients and has the heading "Consumers" with the subheadings "Employers",
"Government Agencies, Individuals and Benefit Brokers." The lower right picture
shows business people and has the heading "payers" with the subheadings
"Government Agencies, Insurance Companies, Managed Care Companies, and Preferred
Provider Organizations."
 
    On the middle right are two layers of plugs which connect the Healtheon logo
identified as the "Healtheon Platform." This section has the heading "The
Healtheon Platform" and is connected by a colored band to the cloud on the left.
The upper level of plugs is identified as applications and has plugs for
"Claims, Transcription, Authorizing, Workflow Engine, M.D. Search, Referrals,
Reporting, Rules Engine, Registration, Eligibility, Person Index, Enrollment,
Lab Orders and Prescriptions." There is a plug called "New Applications" over an
arrow coming from three sources--"Healtheon Applications, 3rd Party Applications
and Legacy Applications." The lower level of plugs is identified as "Data
Objects." One plug, labeled "Data", is over an arrow coming from two
sources--"Legacy Databases" and "Private Networks." The large Healtheon logo is
surrounded by an inner band labeled "Security" and an outer band labeled
"Flexibility," "Usability," "Scalability," "Availability," "Extensibility,"
"Manageability," "Performance" and "Fault Tolerance."
 
    The bottom of the page has a large arrow going from left to right with the
heading "Enabling a New Model for Managing Healthcare Information and
Transactions." To the left of the arrow is the term "Fragmented Legacy
Software", and to the right is the term "Network Services Model." Inside the
arrow is the following text: "HEALTHEON'S VIRTUAL HEALTHCARE NETWORKS connect
providers, payers, consumers and suppliers over the public Internet or private
intranets, and provide services and applications that enable the secure exchange
of information, transactions and simplified workflows across the healthcare
industry. At the center of these networks is THE HEALTHEON PLATFORM, an open
framework for providing mission-critical applications and supporting complex
healthcare transactions, while at the same time ensuring scalability,
availability and security."
<PAGE>
                               PROSPECTUS SUMMARY
 
    YOU SHOULD READ THE FOLLOWING SUMMARY TOGETHER WITH THE MORE DETAILED
INFORMATION REGARDING OUR COMPANY AND THE COMMON STOCK BEING SOLD IN THIS
OFFERING AND OUR CONSOLIDATED FINANCIAL STATEMENTS AND NOTES THERETO APPEARING
ELSEWHERE IN THIS PROSPECTUS.
 
    Healtheon is pioneering the use of the Internet to simplify workflows,
decrease costs and improve the quality of patient care throughout the healthcare
industry. We designed and developed the Healtheon Platform, an Internet-based
information and transaction platform that allows us to create Virtual Healthcare
Networks, or "VHNs," that facilitate and streamline interactions among the
myriad participants in the healthcare industry. The Healtheon VHN solution
includes a suite of services delivered through applications operating on our
Internet-based platform. Our solution enables the secure exchange of information
among disparate healthcare information systems and supports a broad range of
healthcare transactions, including enrollment, eligibility determination,
referrals and authorizations, laboratory and diagnostic test ordering, clinical
data retrieval and claims processing. We provide our own applications on the
Healtheon Platform and also enable third-party applications to operate on the
platform. In addition to VHNs, we provide comprehensive consulting, development,
implementation and network management services to enable our customers to take
full advantage of the capabilities of the Healtheon Platform. To date, our
revenue has been derived primarily from non-Internet network services,
development and consulting services and from management and operation of
customers' information technology infrastructure. We have established strategic
relationships with leading healthcare companies, including UnitedHealth Group,
SmithKline Beecham Clinical Laboratories, Inc., Brown & Toland Physician
Services Organization and Beech Street Corporation. We believe that these
relationships will enhance our application portfolio, provide us with important
specialized industry expertise, increase our market penetration and generate
revenue. An investment in our common stock involves risks and uncertainties,
including the risk that the healthcare industry may be resistant to the adoption
of new information technology due to concerns about government regulation,
patient confidentiality and security. See "Risk Factors."
 
    The Internet's open architecture, universal accessibility and growing
acceptance make it an increasingly important environment for
business-to-business and business-to-consumer interaction. Use of the Internet
is rapidly expanding from simple information publishing, messaging, and data
gathering to critical business transactions and confidential communications. For
many industries, the Internet is connecting previously disconnected business
processes and allowing companies to automate workflows, lower distribution costs
and extend their market reach. We believe the healthcare industry, because of
its size, fragmentation and extreme dependence on information exchange, is
particularly well suited to benefit from greater use of the Internet.
 
    The Healtheon Platform is designed to ensure security, scalability,
reliability, availability and flexibility. The platform includes a CORBA-based
distributed application framework that allows reliable, simultaneous access by
large numbers of users. Open architecture and object-oriented design permit
standards-based integration with legacy systems and third-party applications. A
combination of advanced technologies, including digital encryption, digital
certificates and audit trail tracking, ensures security. The platform is
deployed on redundant, fault tolerant servers with associated software to create
24-hour availability.
 
    Our objective is to become the leading provider of Internet-based
transaction and information services to the healthcare industry. Our strategy
includes:
    - leveraging Internet technology to provide secure transactions and
      communications among a broad range of healthcare participants,
      regardless of their computing platforms;
    - expanding the functionality and transaction capability of our
      platform through the development, acquisition or enabling of
      Internet-based applications;
    - forming additional strategic relationships to increase our
      portfolio of applications and services, to increase the number of
      connected healthcare participants and to provide specialized
      industry expertise for our new applications;
    - targeting regional markets where we can gain critical mass, thereby
      expanding nationally region by region; and
    - employing our usage-based business model to reduce the initial
      investment required by customers to obtain the benefits of high-end
      information technology systems and enable physicians, small
      organizations and individuals to gain access to advanced
      information systems for the first time.
 
    We were incorporated in Delaware in December 1995 and commenced operations
in January 1996. In May 1998, we acquired ActaMed, a leading provider of network
services to the healthcare industry. In August 1998, we acquired Metis, LLC, a
leading consulting, design and development firm focused on Internet and
intranet-based solutions for medical centers and integrated delivery networks.
Our executive offices are located at 4600 Patrick Henry Drive, Santa Clara,
California 95054. Our telephone number is (408) 876-5000. Information contained
on our website is not part of this prospectus.
 
                                       3
<PAGE>
                                  THE OFFERING
 
<TABLE>
<S>                                     <C>
Common stock offered:
  U.S. offering.......................  4,000,000 shares
  International offering..............  1,000,000 shares
    Total.............................  5,000,000 shares
Common stock to be outstanding after
  the offering........................  68,939,542 shares
Use of proceeds.......................  For general corporate purposes, including working capital and
                                        capital expenditures. See "Use of Proceeds."
Dividend policy.......................  We do not anticipate paying any cash dividends in the
                                        foreseeable future.
Nasdaq National Market symbol.........  "HLTH"
</TABLE>
 
    The number of shares of our common stock to be outstanding immediately after
the offering is based on the number of shares outstanding at September 30, 1998.
This number does not take into account 15,979,566 shares of our common stock
subject to options and warrants outstanding or reserved for issuance under our
stock plans at September 30, 1998 and an additional 4,107,321 shares reserved
for issuance under our 1996 Stock Plan as a result of increases in January and
February 1999. This number also does not take into account a warrant to purchase
500,000 shares issued in December 1998. The number of shares to be outstanding
set forth above includes 7,683,341 shares of Series A Preferred Stock issued in
November 1998 which will be converted into common stock at the completion of the
offering and 1,833,333 shares of common stock issued in January 1999 in
connection with an asset purchase agreement with SmithKline Beecham Clinical
Laboratories, Inc., or "SmithKline Labs."
 
                      SUMMARY CONSOLIDATED FINANCIAL DATA
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
 
    The consolidated financial data in this prospectus reflect our acquisition
of ActaMed Corporation, or "ActaMed," on May 19, 1998, which was accounted for
as a pooling of interests. This means that for accounting and financial
reporting purposes, we treat the two companies as if they had always been
combined. The consolidated statement of operations and statement of cash flows
data for the year ended December 31, 1995 are derived solely from the ActaMed
statement of operations for such period because Healtheon did not commence
operations until January 1996. See Notes 1 and 2 of Notes to Consolidated
Financial Statements for a discussion of how we accounted for the acquisition of
ActaMed. See Note 1 of Notes to the Consolidated Financial Statements for an
explanation of the number of shares used in computing basic and diluted net loss
per common share. The balance sheet data at September 30, 1998, as adjusted,
gives effect to the sale of the shares at the initial public offering price,
after deducting estimated underwriting discounts and commissions and our
estimated offering expenses. See "Use of Proceeds" and "Capitalization."
 
<TABLE>
<CAPTION>
                                                                                                NINE MONTHS ENDED
                                                                 YEARS ENDED DECEMBER 31,         SEPTEMBER 30,
                                                              -------------------------------  --------------------
                                                                1995       1996       1997       1997       1998
                                                              ---------  ---------  ---------  ---------  ---------
                                                                                                   (UNAUDITED)
<S>                                                           <C>        <C>        <C>        <C>        <C>
CONSOLIDATED STATEMENT OF OPERATIONS DATA:
Revenue.....................................................  $   2,175  $  11,013  $  13,390  $   7,000  $  33,231
Loss from operations........................................     (3,936)   (16,541)   (25,423)   (19,073)   (35,443)
Net loss applicable to common stockholders..................  $  (4,458) $ (18,606) $ (28,005) $ (21,273) $ (35,860)
Basic and diluted net loss per common share.................  $    (.85) $   (2.83) $   (3.88) $   (3.03) $   (1.24)
Weighted-average shares outstanding used in computing basic
  and diluted net loss per common share.....................      5,246      6,583      7,223      7,019     28,934
Pro forma basic and diluted net loss per common share
  (unaudited)...............................................                        $    (.56)            $    (.74)
Shares used in computing pro forma basic and diluted net
  loss per common share (unaudited).........................                           44,715                47,263
</TABLE>
 
<TABLE>
<CAPTION>
                                                                                             SEPTEMBER 30, 1998
                                                                                          -------------------------
                                                                                           ACTUAL     AS ADJUSTED
                                                                                          ---------  --------------
                                                                                                 (UNAUDITED)
<S>                                                                                       <C>        <C>
BALANCE SHEET DATA:
Cash, cash equivalents and short-term investments.......................................  $   5,392    $   41,692
Working capital (deficit)...............................................................     (6,055)       30,245
Total assets............................................................................     50,271        86,571
Long-term obligations, net of current portion...........................................      1,714         1,714
Stockholders' equity....................................................................     30,226        66,526
</TABLE>
 
                                       4
<PAGE>
                                  RISK FACTORS
 
    YOU SHOULD CAREFULLY CONSIDER THE RISKS DESCRIBED BELOW BEFORE MAKING AN
INVESTMENT DECISION. THE RISKS AND UNCERTAINTIES DESCRIBED BELOW ARE NOT THE
ONLY ONES FACING OUR COMPANY. ADDITIONAL RISKS AND UNCERTAINTIES THAT WE ARE
UNAWARE OF OR THAT WE CURRENTLY DEEM IMMATERIAL ALSO MAY BECOME IMPORTANT
FACTORS THAT AFFECT OUR COMPANY.
 
    IF ANY OF THE FOLLOWING RISKS OCCUR, OUR BUSINESS, FINANCIAL CONDITION OR
RESULTS OF OPERATIONS COULD BE MATERIALLY HARMED. IN THAT CASE, THE TRADING
PRICE OF OUR COMMON STOCK COULD DECLINE, AND YOU MAY LOSE ALL OR PART OF YOUR
INVESTMENT.
 
    THIS PROSPECTUS ALSO CONTAINS FORWARD-LOOKING STATEMENTS THAT INVOLVE RISKS
AND UNCERTAINTIES. OUR ACTUAL RESULTS COULD DIFFER MATERIALLY FROM THOSE
ANTICIPATED IN THESE FORWARD-LOOKING STATEMENTS AS A RESULT OF CERTAIN FACTORS,
INCLUDING THE RISKS FACED BY US DESCRIBED BELOW AND ELSEWHERE IN THIS
PROSPECTUS.
 
OUR BUSINESS IS DIFFICULT TO EVALUATE BECAUSE OUR OPERATING HISTORY IS LIMITED
  AND OUR BUSINESS MODEL IS UNPROVEN
 
    Because we have recently begun operations, it is difficult to evaluate our
business and our prospects. Our revenue and income potential is unproven and our
business model is still emerging. Our historical financial information is of
limited value in projecting our future operating results because of our limited
operating history as a combined organization and the emerging nature of our
markets. We began operations in January 1996 and until recently had not earned
significant revenue. We have lost money since we began operations and, as of
September 30, 1998, we had an accumulated deficit of $85.2 million. In May 1998,
we acquired ActaMed and in August 1998, we acquired Metis, LLC. We currently
derive our revenue primarily from proprietary non-Internet network services
offered by ActaMed, from development and consulting services and from managing
and operating our customers' information technology infrastructures. We plan to
invest heavily in acquisitions, infrastructure development, applications
development and sales and marketing. As a result, we expect that we will
continue to lose money through 1999 and we may never achieve or sustain
profitability. See "Management's Discussion and Analysis of Financial Condition
and Results of Operations."
 
THE HEALTHCARE INDUSTRY MAY NOT ACCEPT OUR SOLUTIONS
 
    To be successful, we must attract a significant number of customers
throughout the healthcare industry. To date, the healthcare industry has been
resistant to adopting new information technology solutions. Electronic
information exchange and transaction processing by the healthcare industry is
still developing. We believe that complexities in the nature of the healthcare
transactions that must be processed have hindered the development and acceptance
of information technology solutions by the industry. Conversion from traditional
methods to electronic information exchange may not occur as rapidly as we expect
it will. Even if the conversion does occur as rapidly as we expect, healthcare
industry participants may use applications and services offered by others.
 
    We believe that we must gain significant market share with our applications
and services before our competitors introduce alternative products, applications
or services with features similar to our current or proposed offerings. Our
business plan is based on our belief that the value and market appeal of our
solution will grow as the number of participants and the scope of the
transaction services available on our platform increase. We may not achieve the
critical mass of users we believe is necessary to become successful. In
addition, we expect to generate a significant portion of our revenue from
subscription and transaction-based fees. Consequently, any significant shortfall
in the number of users or transactions occurring over our platform would
adversely affect our financial results. See "Business -- Industry Background."
 
                                       5
<PAGE>
WE RELY ON STRATEGIC RELATIONSHIPS TO GENERATE REVENUE
 
    To be successful, we must establish and maintain strategic relationships
with leaders in a number of healthcare industry segments. This is critical to
our success because we believe that these relationships will enable us to:
 
    - extend the reach of our applications and services to the various
      participants in the healthcare industry;
 
    - obtain specialized healthcare expertise;
 
    - develop and deploy new applications;
 
    - further enhance the Healtheon brand; and
 
    - generate revenue.
 
    Entering into strategic relationships is complicated because some of our
current and future partners may decide to compete with us. In addition, we may
not be able to establish relationships with key participants in the healthcare
industry if we have established relationships with competitors of these key
participants. Consequently, it is important that we are perceived as independent
of any particular customer or partner. Moreover, many potential partners may
resist working with us until our applications and services have been
successfully introduced and have achieved market acceptance.
 
    Once we have established strategic relationships, we will depend on our
partners' ability to generate increased acceptance and use of our platform,
applications and services. To date, we have established only a limited number of
strategic relationships and these relationships are in the early stages of
development. We have limited experience in establishing and maintaining
strategic relationships with healthcare industry participants. If we lose any of
these strategic relationships or fail to establish additional relationships, or
if our strategic partners fail to actively pursue additional business
relationships and partnerships, we would not be able to execute our business
plans and our business would suffer significantly. On February 9, 1999,
SmithKline Beecham announced that it has agreed to sell SmithKline Labs to Quest
Diagnostics, Incorporated. SmithKline Labs has been one of our strategic
partners since December 1997, and our relationship with them has been
beneficial. Our agreements with SmithKline Labs will remain in effect as a
result of the acquisition. However, we will need to work with a new business
partner, which involves risks such as different customer requirements and
working relationships. At this time, we are not aware of Quest's intentions
regarding our relationship with SmithKline Labs. Our business could be adversely
affected if Quest does not pursue the relationship to the same extent as
SmithKline Labs. In addition, our ability to take advantage of our relationship
with SmithKline Labs may be impaired because the attention of management of the
combining companies may be diverted during and after the acquisition. We may not
experience increased use of our platform, applications and services even if we
establish and maintain these strategic relationships. For additional information
regarding our strategic relationships, see "Business -- Strategy" and "--
Strategic Relationships."
 
OUR BUSINESS WILL SUFFER IF WE DO NOT EXPAND OUR SUITE OF APPLICATIONS
 
    Our business will suffer if we do not expand the breadth of our applications
quickly. We currently offer a limited number of applications on our platform and
our future success depends on quickly introducing new applications in several
healthcare segments. We do not have the internal resources and specialized
healthcare expertise to develop all these applications independently.
Consequently, we must rely on a combination of internal development, strategic
relationships, licensing and acquisitions to develop these applications. Each of
our applications, regardless of how it was developed, must be integrated and
customized to operate with existing customer legacy computer systems and our
platform. Developing, integrating and customizing these applications will be
expensive and time consuming. Even if we are successful, these applications may
never achieve market acceptance, which could also cause our business to suffer.
 
                                       6
<PAGE>
WE MUST ACQUIRE TECHNOLOGIES AND COMPANIES TO INCREASE OUR CUSTOMER BASE
 
    We expect to continue to acquire technologies and other healthcare
technology companies to increase the number and variety of applications on our
platform and to increase our customer base. For example, in May 1998 we acquired
ActaMed, and in August 1998 we acquired substantially all the assets of Metis,
LLC. To be successful, we will need to identify applications, technologies and
businesses that are complementary to ours, integrate disparate technologies and
corporate cultures and manage a geographically dispersed company. Acquisitions
could divert our attention from other business concerns and expose us to
unforeseen liabilities or risks associated with entering new markets. Finally,
we may lose key employees while integrating these new companies.
 
    Integrating newly acquired organizations and technologies into our company
could be expensive, time consuming and may strain our resources. In addition, we
may lose our current customers if any acquired companies have relationships with
competitors of our customers. Consequently, we may not be successful in
integrating any acquired businesses or technologies and may not achieve
anticipated revenue and cost benefits. The healthcare industry is consolidating
and we expect that we will face intensified competition for acquisitions,
especially from larger, better-funded organizations. If we fail to execute our
acquisition strategy successfully for any reason, our business will suffer
significantly.
 
    We intend to pay for some of our acquisitions by issuing additional common
stock and this could dilute our stockholders. We may also use cash to buy
companies or technologies in the future. If we do use cash, we may need to incur
debt to pay for these acquisitions. Acquisition financing may not be available
on favorable terms or at all. In addition, we may be required to amortize
significant amounts of goodwill and other intangible assets in connection with
future acquisitions, which would materially harm our results of operations.
 
WE MUST MANAGE OUR GROWTH
 
    We have rapidly and significantly expanded our operations and expect to
continue to do so. This growth has placed, and is expected to continue to place,
a significant strain on our managerial, operational, financial and other
resources. As of September 30, 1998, we have grown to 613 employees and
independent contractors, from 176 employees and independent contractors on
December 31, 1997. A large portion of this increase resulted from our
acquisitions of ActaMed in May 1998 and Metis, LLC in August 1998, which
increased our payroll by 230 employees. We expect to hire a significant number
of new employees to support our business.
 
    Our current information systems, procedures and controls may not continue to
support our operations and may hinder our ability to exploit the market for
healthcare applications and services. We are in the process of evaluating our
accounting and management information systems and anticipate that we may
implement new systems within the next twelve months. We could experience
interruptions to our business while we transition to new systems.
 
OUR BUSINESS WILL SUFFER IF COMMERCIAL USERS DO NOT ACCEPT INTERNET SOLUTIONS
 
    Our business model depends on the adoption of Internet solutions by
commercial users. Our business could suffer dramatically if Internet solutions
are not accepted or not perceived to be effective. The Internet may not prove to
be a viable commercial marketplace for a number of reasons, including:
 
    - inadequate development of the necessary infrastructure for communication
      speed, access and server reliability;
 
    - security and confidentiality concerns;
 
    - lack of development of complementary products, such as high-speed modems
      and high-speed communication lines;
 
    - implementation of competing technologies;
 
                                       7
<PAGE>
    - delays in the development or adoption of new standards and protocols
      required to handle increased levels of Internet activity; and
 
    - governmental regulation.
 
    We expect Internet use to grow in number of users and volume of traffic. The
Internet infrastructure may be unable to support the demands placed on it by
this continued growth.
 
    Growth in the demand for our applications and services depends on the
adoption of Internet solutions by healthcare participants, which requires the
acceptance of a new way of conducting business and exchanging information. The
healthcare industry, in particular, relies on legacy systems that may be unable
to benefit from our Internet-based platform. To maximize the benefits of our
platform, healthcare participants must be willing to allow sensitive information
to be stored in our databases. We can process transactions for healthcare
participants that maintain information on their own proprietary databases.
However, the benefits of our connectivity and sophisticated information
management solution are limited under these circumstances. Customers using
legacy and client-server systems may refuse to adopt new systems when they have
made extensive investment in hardware, software and training for older systems.
 
PERFORMANCE OR SECURITY PROBLEMS WITH OUR SYSTEMS COULD DAMAGE OUR BUSINESS
 
    Our customer satisfaction and our business could be harmed if we or our
customers experience any system delays, failures or loss of data. We currently
process substantially all our customer transactions and data at our facilities
in Santa Clara, California and Atlanta, Georgia. Although we have safeguards for
emergencies, we do not have backup facilities to process information if either
of these facilities is not functioning. The occurrence of a major catastrophic
event or other system failure at either the Santa Clara or the Atlanta facility
could interrupt data processing or result in the loss of stored data. In
addition, we depend on the efficient operation of Internet connections from
customers to our systems. These connections, in turn, depend on the efficient
operation of Web browsers, Internet service providers and Internet backbone
service providers, all of which have had periodic operational problems or
experienced outages.
 
    A material security breach could damage our reputation or result in
liability to us. We retain confidential customer and patient information in our
processing centers. Therefore, it is critical that our facilities and
infrastructure remain secure and that our facilities and infrastructure are
perceived by the marketplace to be secure. Despite the implementation of
security measures, our infrastructure may be vulnerable to physical break-ins,
computer viruses, programming errors, attacks by third parties or similar
disruptive problems.
 
TECHNOLOGY MAY CHANGE FASTER THAN WE CAN UPDATE OUR APPLICATIONS AND SERVICES
 
    Healthcare information exchange and transaction processing is a relatively
new and evolving market. The pace of change in our markets is rapid and there
are frequent new product introductions and evolving industry standards. We may
be unsuccessful in responding to technological developments and changing
customer needs. In addition, our applications and services offerings may become
obsolete due to the adoption of new technologies or standards. See "Business --
Development and Engineering."
 
OUR PLATFORM INFRASTRUCTURE AND ITS SCALABILITY ARE NOT PROVEN
 
    So far, we have processed a limited number and variety of transactions over
our platform. Similarly, a limited number of healthcare participants use our
platform. Our systems may not accommodate increased use while maintaining
acceptable overall performance. We must continue to expand and adapt our network
infrastructure to accommodate additional users, increased transaction volumes
and changing customer requirements. This expansion and adaptation will be
expensive and will divert our attention from other activities.
 
    Many of our service agreements contain performance standards. If we fail to
meet these standards, our customers could terminate their agreements with us.
The loss of any of our service agreements would directly
 
                                       8
<PAGE>
and significantly impact our business. We may be unable to expand or adapt our
network infrastructure to meet additional demand or our customers' changing
needs on a timely basis and at a commercially reasonable cost, or at all.
 
OUR REVENUES ARE CONCENTRATED IN A FEW CUSTOMERS
 
    We expect that we will generate a significant portion of our revenue from a
small number of customers for the next few years. If we do not generate as much
revenue from these customers as we expect, or if we lose any of these customers,
our revenue will be significantly reduced which would harm our business. For
example, we receive a substantial majority of our revenue from four customers.
UnitedHealth Group, SmithKline Beecham Clinical Laboratories, Inc., Brown &
Toland Physician Services Organization and Beech Street Corporation each
accounted for over 10% and together accounted for approximately 90% of our total
revenue for the nine months ended September 30, 1998. In addition, UnitedHealth
Group and Brown & Toland each accounted for over 10% and together accounted for
approximately 70% of our total revenue for the year ended December 31, 1997.
Customers who also own shares of our stock, including UnitedHealth Group and
SmithKline Labs, accounted for 55% of our total revenue in the year ended
December 31, 1997 and 43% of our total revenue for the nine months ended
September 30, 1998. UnitedHealth Group will own approximately 13.3% of our stock
after this offering. Similarly, SmithKline Labs will own approximately 9.1% of
our stock after this offering. See "Management's Discussion and Analysis of
Financial Condition and Results of Operations" and "Business -- Strategic
Relationships."
 
WE FACE SIGNIFICANT COMPETITION
 
    The market for healthcare information services is intensely competitive,
rapidly evolving and subject to rapid technological change. Many of our
competitors have greater financial, technical, product development, marketing
and other resources than we have. These organizations may be better known and
have more customers than us. We may be unable to compete successfully against
these organizations.
 
    Many of our competitors have announced or introduced Internet strategies
that will compete with our applications and services. We have many competitors,
including:
 
    - healthcare information software vendors, including HBO & Company and
      Shared Medical Systems Corporation;
 
    - healthcare electronic data interchange companies, including ENVOY
      Corporation and National Data Corporation;
 
    - large information technology consulting service providers, including
      Andersen Consulting, International Business Machines Corporation and
      Electronic Data Systems Corporation; and
 
    - small regional organizations.
 
In addition, we expect that major software information systems companies and
others specializing in the healthcare industry will offer competitive
applications or services. Some of our large customers may also compete with us.
See "Business -- Competition."
 
CHANGES IN THE HEALTHCARE INDUSTRY COULD ADVERSELY AFFECT OUR BUSINESS
 
    The healthcare industry is highly regulated and is subject to changing
political, economic and regulatory influences. These factors affect the
purchasing practices and operation of healthcare organizations. Changes in
current healthcare financing and reimbursement systems could cause us to make
unplanned enhancements of applications or services, or result in delays or
cancellations of orders or in the revocation of endorsement of our applications
and services by healthcare participants. Federal and state legislatures have
periodically considered programs to reform or amend the U.S. healthcare system
at both the federal and state level. These programs may contain proposals to
increase governmental involvement in healthcare, lower reimbursement rates or
otherwise change the environment in which healthcare industry participants
 
                                       9
<PAGE>
operate. Healthcare industry participants may respond by reducing their
investments or postponing investment decisions, including investments in our
applications and services. We do not know what effect any proposals would have
on our business.
 
    Many healthcare providers are consolidating to create integrated healthcare
delivery systems with greater market power. These providers may try to use their
market power to negotiate price reductions for our applications and services. If
we were forced to reduce our prices, our operating results would suffer. As the
healthcare industry consolidates, competition for customers will become more
intense and the importance of acquiring each customer will become greater.
 
GOVERNMENT REGULATION COULD ADVERSELY AFFECT OUR BUSINESS
 
    Our business is subject to government regulation. Existing as well as new
laws and regulations could adversely affect our business. Laws and regulations
may be adopted with respect to the Internet or other on-line services covering
issues such as:
 
    - user privacy;
 
    - pricing;
 
    - content;
 
    - copyrights;
 
    - distribution; and
 
    - characteristics and quality of products and services.
 
    Moreover, the applicability to the Internet of existing laws in various
jurisdictions governing issues such as property ownership, sales and other
taxes, libel and personal privacy is uncertain and may take years to resolve.
Demand for our applications and services may be affected by additional
regulation of the Internet. For example, until recently current Health Care
Financing Administration guidelines prohibited transmission of Medicare
eligibility information over the Internet.
 
    We are subject to extensive regulation relating to the confidentiality and
release of patient records. Additional legislation governing the distribution of
medical records has been proposed at both the state and federal level. It may be
expensive to implement security or other measures designed to comply with any
new legislation. Moreover, we may be restricted or prevented from delivering
patient records electronically.
 
    Legislation currently being considered at the federal level could affect our
business. For example, the Health Insurance Portability and Accountability Act
of 1996 mandates the use of standard transactions, standard identifiers,
security and other provisions by the year 2000. We are designing our platform
and applications to comply with these proposed regulations; however, until these
regulations become final, they could change, which could cause us to use
additional resources and lead to delays in order to revise our platform and
applications. In addition, our success depends on other healthcare participants
complying with these regulations.
 
    Some computer applications and software are considered medical devices and
are subject to regulation by the United States Food and Drug Administration, or
the "FDA." We do not believe that our current applications or services are
subject to FDA regulation. We may expand our application and service offerings
into areas that subject us to FDA regulation. We have no experience in complying
with FDA regulations. We believe that complying with FDA regulations would be
time consuming, burdensome and expensive and could delay our introduction of new
applications or services. See "Business -- Governmental Regulations."
 
OUR QUARTERLY OPERATING RESULTS MAY VARY
 
    Our quarterly operating results have varied in the past and we expect that
they will continue to vary in future periods depending on a number of factors
described below and elsewhere in this "Risk Factor" section of the prospectus.
Our services revenue in any quarter depends on our mix of consulting and
transaction fee revenue and our ability to meet project milestones and customer
expectations.
 
                                       10
<PAGE>
    To increase our revenue in any operating period, we must enter new markets
and develop new applications and services offerings required by our customers.
Our operating results will be harmed if we experience delays in developing new
applications and services for our customers or defects in our applications.
 
    We expect to increase activities and spending in substantially all of our
operational areas. We base our expense levels in part upon our expectations
concerning future revenue and these expense levels are relatively fixed in the
short-term. If we have lower revenue, we may not be able to reduce our spending
in the short-term in response. Any shortfall in revenue would have a direct
impact on our results of operations. See "Management's Discussion and Analysis
of Financial Condition and Results of Operations." For these and other reasons,
we may not meet the earnings estimates of securities analysts or investors and
our stock price could suffer.
 
WE MAY FACE PRODUCT-RELATED LIABILITIES
 
    Although we and our customers test our applications, they may contain
defects or result in system failures. In addition, our platform may experience
problems in security, availability, scalability or other critical features.
These defects or problems could result in the loss of or delay in generating
revenue, loss of market share, failure to achieve market acceptance, diversion
of development resources, injury to our reputation or increased insurance costs.
 
    Many of our strategic relationships and services agreements involve
providing critical information technology services to our clients' businesses.
Providing these services is complex because our clients have complex computing
system environments. If we fail to meet our clients' expectations, our
reputation could suffer and we could be liable for damages. In addition, patient
care could suffer and we could be liable if our systems fail to deliver correct
information in a timely manner. Our insurance may not protect us from this risk.
Finally, we could become liable if confidential information is disclosed
inappropriately.
 
    Our contracts limit our liability arising from our errors; however, these
provisions may not be enforceable and may not protect us from liability. While
we have general liability insurance that we believe is adequate, including
coverage for errors and omissions, we may not be able to maintain this insurance
on reasonable terms in the future. In addition, our insurance may not be
sufficient to cover large claims and our insurer could disclaim coverage on
claims. If we are liable for an uninsured or underinsured claim or if our
premiums increase significantly, our financial condition could be materially
harmed.
 
OUR PROPRIETARY TECHNOLOGY MAY BE SUBJECTED TO INFRINGEMENT CLAIMS OR MAY BE
  INFRINGED UPON
 
    Our intellectual property is important to our business. We expect that we
could be subject to intellectual property infringement claims as the number of
our competitors grows and the functionality of our applications overlaps with
competitive offerings. These claims, even if not meritorious, could be expensive
and divert our attention from operating our company. If we become liable to
third parties for infringing their intellectual property rights, we would be
required to pay a substantial damage award and to develop noninfringing
technology, obtain a license or cease selling the applications that contain the
infringing intellectual property. We may be unable to develop noninfringing
technology or obtain a license on commercially reasonable terms, or at all. In
addition, we may not be able to protect against misappropriation of our
intellectual property. Third parties may infringe upon our intellectual property
rights, we may not detect this unauthorized use and we may be unable to enforce
our rights. See "Business -- Intellectual Property."
 
LENGTHY SALES AND IMPLEMENTATION CYCLES FOR OUR SOLUTIONS COULD ADVERSELY AFFECT
  OUR REVENUE GROWTH
 
    A key element of our strategy is to market our solutions directly to large
healthcare organizations. We are unable to control many of the factors that will
influence our customers' buying decisions. We expect that the sales and
implementation process will be lengthy and will involve a significant technical
evaluation and
 
                                       11
<PAGE>
commitment of capital and other resources by our customers. The sale and
implementation of our solutions are subject to delays due to our customers'
internal budgets and procedures for approving large capital expenditures and
deploying new technologies within their networks.
 
    We will need to expend substantial resources to integrate our applications
with the existing legacy and client-server architectures of large healthcare
organizations. We have limited experience in integrating our applications with
large, complex architectures, and we may experience delays in the integration
process. These delays would, in turn, delay our ability to generate revenue from
these applications and could adversely affect our results of operations.
 
WE FACE RISKS RELATED TO THE YEAR 2000
 
    Issues with respect to the Year 2000 could affect the performance of our or
our customers' computer systems. Two of our systems, SBCL SCAN, or "SCAN," and
ProviderLink, are not Year 2000 compliant. Our revenue from these systems
accounted for approximately 43% of our total revenue in the first nine months of
1998. We plan to release Year 2000 upgrades to these systems in early 1999. We
estimate the cost of these Year 2000 upgrades to SCAN and ProviderLink to be
less than $1.0 million. In addition, our SCAN product is installed on
approximately 4,650 workstations located in physician offices. Many of these
workstations are not Year 2000 compliant and we must upgrade or replace them. We
could experience delays and cost overruns in developing these upgrades. In
addition, it may be difficult to convince physicians to implement these
upgrades. Our revenue from SCAN and ProviderLink could decrease if we experience
delays in upgrading these applications and workstations. In addition, we may not
identify all of our applications and systems that must be modified to be Year
2000 compliant and may need to spend additional amounts to repair or modify our
applications and systems. In certain of our agreements, we warrant that our
applications and services are Year 2000 compliant. If they are not compliant,
our customers could terminate the agreements and we could be liable for damages.
 
    We also depend on other healthcare participants to be Year 2000 compliant.
Many of these organizations are not Year 2000 compliant, and we do not know what
affect this would have on our systems. We could be liable for the failure of our
platform even if the failure was caused by someone else. Furthermore, the costs
to our customers of becoming Year 2000 compliant may result in reduced funds
being available to purchase and implement our applications and services. See
"Management's Discussion and Analysis of Financial Condition and Results of
Operations -- Year 2000 Compliance."
 
WE MAY NEED TO OBTAIN FUTURE CAPITAL
 
    We expect that the money generated from this offering, combined with our
current cash resources and credit facilities, will be sufficient to meet our
requirements for at least the next 12 months. However, we may need to raise
additional financing to support expansion, develop new or enhanced applications
and services, respond to competitive pressures, acquire complementary businesses
or technologies or take advantage of unanticipated opportunities. We may need to
raise additional funds by selling debt or equity securities, by entering into
strategic relationships or through other arrangements. We may be unable to raise
any additional amounts on reasonable terms when they are needed.
 
OUR COMMON STOCK PRICE MAY BE VOLATILE
 
    You may not be able to resell your shares at or above the initial public
offering price due to a number of factors, including:
 
    - actual or anticipated quarterly variations in our operating results;
 
    - changes in expectations of future financial performance or changes in
      estimates of securities analysts;
 
    - announcements of technological innovations;
 
    - announcements relating to strategic relationships;
 
    - customer relationship developments; and
 
    - conditions affecting the Internet or healthcare industries, in general.
 
                                       12
<PAGE>
    The trading price of our common stock may be volatile. The stock market in
general, and the market for technology and Internet-related companies in
particular, has experienced extreme volatility that often has been unrelated to
the operating performance of particular companies. These broad market and
industry fluctuations may adversely affect the trading price of our common
stock, regardless of our actual operating performance.
 
    In the past, following periods of volatility in the market price of a
company's securities, securities class action litigation has often been
instituted. If this were to happen to Healtheon, litigation would be expensive
and would divert management's attention.
 
    The initial public offering price was established by negotiation between the
U.S. underwriters and Healtheon. You should read the "Underwriters" section for
a more complete discussion of the factors determining the initial public
offering price.
 
OUR BUSINESS WILL BE ADVERSELY AFFECTED IF WE CANNOT ATTRACT AND RETAIN KEY
  PERSONNEL
 
    Our success will depend significantly on our senior management team and
other key employees. We need to attract, integrate, motivate and retain
additional highly skilled technical people. In particular, we need to attract
experienced professionals capable of developing, selling and installing complex
healthcare information systems. We face intense competition for these people.
Our executive management team, including W. Michael Long, our Chief Executive
Officer, and Pavan Nigam, our Vice President, Engineering, is critical to our
success. We do not maintain key person life insurance for anyone.
 
WE HAVE CERTAIN ANTI-TAKEOVER DEFENSES THAT COULD DELAY OR PREVENT AN
  ACQUISITION OF OUR COMPANY
 
    Certain provisions of our certificate of incorporation and bylaws and the
provisions of Delaware law could have the effect of delaying, deferring or
preventing an acquisition of Healtheon. For example, our board of directors is
divided into three classes to serve staggered three-year terms, our stockholders
may not take actions by written consent and our stockholders are limited in
their ability to make proposals at stockholder meetings. See "Description of
Capital Stock" for a further discussion of these provisions.
 
FUTURE SALES OF SHARES COULD AFFECT OUR STOCK PRICE
 
    The market price for our common stock could fall dramatically if our
stockholders sell large amounts of our common stock in the public market
following this offering. These sales, or the possibility that these sales may
occur, could make it more difficult for us to sell equity or equity-related
securities in the future. The number of shares of common stock available for
sale in the public market is limited by restrictions under federal securities
law and by certain "lock-up" agreements that our stockholders have entered into
with the underwriters. The lock-up agreements restrict our stockholders from
selling or otherwise disposing of any of their shares for a period of 180 days
after the date of this prospectus without the prior written consent of Morgan
Stanley & Co. Incorporated. Morgan Stanley & Co. Incorporated may, however, in
its sole discretion and without notice, release all or any portion of the shares
from the restrictions in the lock-up agreements.
 
                                       13
<PAGE>
    After this offering, we will have outstanding 67,195,893 shares of common
stock, based upon shares outstanding as of November 30, 1998, assuming
conversion of all outstanding Series A preferred stock into common stock on the
closing of this offering, no exercise of the underwriters' overallotment option
and no exercise of outstanding options or warrants. These shares will become
eligible for sale in the public market as follows:
 
<TABLE>
<CAPTION>
NUMBER OF SHARES         DATE ELIGIBLE FOR PUBLIC RESALE
- -----------------------  ---------------------------------------------------------------------
<S>                      <C>
 5,658,184.............  Date of this prospectus (includes the 5,000,000 shares sold in this
                           offering)
52,254,368.............  180 days after the date of this prospectus
 9,283,341.............  At various times thereafter through November 6, 1999
</TABLE>
 
    In addition, in January 1999 we issued 1,833,333 shares to SmithKline Labs.
These shares will become eligible for sale, subject to the volume and other
limitations of Rule 144 of the Securities Act, on January 19, 2000.
 
    Any shares that may be purchased in this offering by our "affiliates," as
defined in Rule 144, will be subject to the volume and other selling limitations
under Rule 144. All but 10,437,264 of the shares eligible for sale at the 180th
day after the date of this prospectus or afterward will be subject initially to
certain volume and other limitations under Rule 144.
 
    On or prior to the 180th day following the date of this prospectus, we
intend to register for resale an additional 13,811,659 shares of common stock
reserved for issuance under our employee stock plans based upon the number of
shares reserved for issuance as of November 30, 1998. In addition, the holders
of approximately 50,007,164 shares of our common stock have the right to require
us to register their shares for sale to the public. If these holders cause a
large number of shares to be registered and sold in the public market, our stock
price could fall materially. See "Shares Eligible for Future Sale."
 
OUR OFFICERS, DIRECTORS AND AFFILIATED ENTITIES WILL HAVE SIGNIFICANT CONTROL OF
  HEALTHEON
 
    After this offering, our directors and management will own or control
approximately 68.1% of our common stock. If these people act together, they will
be able to significantly influence the management and affairs of Healtheon and
will have the ability to control all matters requiring stockholder approval.
This concentration of ownership may have the effect of delaying, deferring or
preventing an acquisition of Healtheon and may adversely affect the market price
of our common stock.
 
OUR CURRENT STOCKHOLDERS WILL BENEFIT FROM THIS OFFERING
 
    Based on the number of shares of common stock outstanding as of September
30, 1998, existing stockholders have paid an average of $2.06 per share for
their common stock, which is considerably less than the amount to be paid by
investors who purchase in this offering. New investors in this offering will
experience an immediate dilution of $7.28 per share, also based on the number of
outstanding shares as of September 30, 1998. This offering will also create a
public market for the resale of shares held by existing investors, and
substantially increase the market value of those shares. See "Dilution" and
"Principal Stockholders."
 
                                       14
<PAGE>
                                USE OF PROCEEDS
 
    The net proceeds from the sale of the 5,000,000 shares of common stock in
this offering are estimated to be approximately $36.3 million, at the initial
public offering price and after deducting underwriting discounts and commissions
and our estimated offering expenses. If the U.S. underwriters' over-allotment
option is exercised in full, the net proceeds would be approximately $41.9
million. The principal purposes of this offering are to obtain additional
capital, to create a public market for Healtheon's common stock, to enhance the
ability of Healtheon to acquire other businesses, products or technologies, and
to facilitate future access by Healtheon to public equity markets.
 
    Healtheon currently expects to use the net proceeds of this offering for
general corporate purposes, including working capital and capital expenditures.
Healtheon may also use a portion of the net proceeds of this offering to acquire
or invest in complementary businesses or technologies, although Healtheon has no
present commitments or agreements with respect to any acquisition or investment.
However, Healtheon from time to time enters into nondisclosure agreements with
third parties for the purpose of evaluating strategic transactions involving
complementary businesses or technologies. Healtheon intends to invest the
proceeds of this offering in short-term, interest-bearing, investment grade
securities pending use of the proceeds.
 
                                DIVIDEND POLICY
 
    Healtheon has never declared or paid any cash dividends on its common stock
or other securities and does not intend to pay any cash dividends with respect
to its common stock in the foreseeable future. Healtheon intends to retain any
earnings for use in the operation of its business and to fund future growth. In
addition, the terms of Healtheon's credit agreement prohibit the payment of cash
dividends on its capital stock.
 
                                       15
<PAGE>
                                 CAPITALIZATION
 
    The following table sets forth the total capitalization of Healtheon as of
September 30, 1998 on an actual basis and on an as adjusted basis to reflect the
receipt by Healtheon of the estimated net proceeds from the sale of the
5,000,000 shares of common stock in this offering at the initial public offering
price after deducting underwriting discounts and commissions and our estimated
offering expenses.
 
<TABLE>
<CAPTION>
                                                                                                   SEPTEMBER 30, 1998
                                                                                                 ----------------------
                                                                                                  ACTUAL    AS ADJUSTED
                                                                                                 ---------  -----------
                                                                                                      (UNAUDITED)
                                                                                                     (IN THOUSANDS)
<S>                                                                                              <C>        <C>
Capital lease obligations, net of current portion..............................................  $   1,714   $   1,714
                                                                                                 ---------  -----------
Stockholders' equity:
  Convertible preferred stock, $.0001 par value; no shares authorized, no shares issued or
   outstanding, actual; 5,000,000 shares authorized, no shares issued or outstanding, as
   adjusted....................................................................................     --          --
  Common stock, $.0001 par value; 75,000,000 shares authorized, 54,422,868 shares issued and
   outstanding, actual; 150,000,000 shares authorized, 59,422,868 shares issued and
   outstanding, as adjusted....................................................................          5           6
Additional paid-in capital.....................................................................    119,645     155,944
Deferred stock compensation....................................................................     (4,184)     (4,184)
Accumulated deficit............................................................................    (85,240)    (85,240)
                                                                                                 ---------  -----------
    Total stockholders' equity.................................................................     30,226      66,526
                                                                                                 ---------  -----------
      Total capitalization.....................................................................  $  31,940   $  68,240
                                                                                                 ---------  -----------
                                                                                                 ---------  -----------
</TABLE>
 
    The share numbers above exclude:
 
    - 11,186,473 shares of common stock issuable upon the exercise of options
      outstanding at September 30, 1998, with a weighted average exercise price
      of $2.33 per share;
 
    - 2,715,853 shares reserved for issuance under our 1996 Stock Plan and our
      1998 Purchase Plan at September 30, 1998 and an additional 4,107,321
      shares reserved for issuance under our 1996 Stock Plan as a result of
      increases in January and February 1999;
 
    - 2,077,240 shares of common stock issuable upon the exercise of warrants
      outstanding at September 30, 1998, with a weighted average exercise price
      of $2.81 per share;
 
    - 500,000 shares of common stock subject to a warrant with an exercise price
      of $10.40 per share issued to a customer in December 1998;
 
    - 7,683,341 shares of Series A convertible preferred stock issued in
      November 1998 for $46.1 million in cash proceeds;
 
    - options to purchase common stock granted and shares of common stock issued
      under restricted stock purchase agreements equal to a total of 5,625,882
      shares from October 1998 to February 1999 with a weighted-average exercise
      or purchase price of $5.02 per share; and
 
    - 1,833,333 shares of common stock issued in connection with a December 1998
      Asset Purchase Agreement with SmithKline Beecham Clinical Laboratories,
      Inc.
 
        On October 20, 1998, Healtheon offered to reprice options granted from
    July 1998 through October 1998. Under this repricing, option holders could
    surrender their original option in exchange for a new option with a new
    vesting start date and an exercise price of $3.55 per share. Options for a
    total of 2,057,950 shares were canceled and reissued. On December 14, 1998,
    455,000 shares of common stock issued in July 1998 pursuant to restricted
    stock purchase agreements were repurchased.
 
        See "Management--Employee Benefit Plans," "Description of Capital Stock"
    and Notes 10, 11 and 14 of Notes to Consolidated Financial Statements.
 
                                       16
<PAGE>
                                    DILUTION
 
    The net tangible book value of Healtheon as of September 30, 1998 was
approximately $6.5 million, or $0.12 per share. Net tangible book value per
share is determined by dividing our total net tangible book value, which is
total tangible assets less total liabilities, by the number of shares of common
stock at that date. Dilution per share represents the difference between the
amount per share paid by purchasers of shares of common stock in this offering
and the net tangible book value per share of common stock immediately after
completion of this offering. After giving effect to the sale of 5,000,000 shares
of common stock offered by Healtheon, at the initial public offering price and
after deducting underwriting discounts and commissions and estimated offering
expenses payable by Healtheon, and the application of the estimated net
proceeds, our net tangible book value at September 30, 1998 would have been
$42.8 million, or $0.72 per share. This represents an immediate increase in pro
forma net tangible book value to existing stockholders of $0.60 per share and an
immediate dilution to new investors of $7.28 per share. The following table
illustrates the per share dilution:
 
<TABLE>
<CAPTION>
<S>                                                                                <C>          <C>
Assumed initial public offering price per share..................................                $    8.00
  Net tangible book value per share as of September 30, 1998.....................         .12
  Increase per share attributable to new investors...............................         .60
                                                                                        -----
Net tangible book value per share after this offering............................                $     .72
                                                                                                     -----
Dilution per share to new public investors.......................................                $    7.28
                                                                                                     -----
                                                                                                     -----
</TABLE>
 
    The following table sets forth, on a pro forma basis, as of September 30,
1998, the difference between the number of shares of common stock purchased from
Healtheon, the total consideration paid and the average price per share paid by
existing stockholders and by the new investors. Amounts in the table are
calculated at the initial public offering price and before deducting estimated
underwriting discounts and commissions and estimated offering expenses payable
by Healtheon:
 
<TABLE>
<CAPTION>
                                          SHARES PURCHASED           TOTAL CONSIDERATION
                                      -------------------------  ---------------------------   AVERAGE PRICE
                                         NUMBER       PERCENT        AMOUNT        PERCENT       PER SHARE
                                      ------------  -----------  --------------  -----------  ---------------
<S>                                   <C>           <C>          <C>             <C>          <C>
Existing stockholders...............    54,422,868        91.6%  $  112,287,000        73.7%     $    2.06
New public investors................     5,000,000         8.4       40,000,000        26.3           8.00
                                      ------------       -----   --------------       -----
    Total...........................    59,422,868       100.0%  $  152,287,000       100.0%          2.56
                                      ------------       -----   --------------       -----
                                      ------------       -----   --------------       -----
</TABLE>
 
    As of September 30, 1998, there were options outstanding to purchase a total
of 11,186,473 shares of common stock, with a weighted average exercise price of
$2.33 per share, and warrants to purchase a total of 2,077,240 shares of common
stock, with a weighted average exercise price of $2.81 per share. From October
through December 1998, Healtheon granted options to purchase common stock and
issued shares of common stock under restricted stock purchase agreements equal
to a total of 1,518,257 shares, with a weighted average exercise or purchase
price of $3.55 per share. To the extent that any of the outstanding options or
warrants are exercised, there will be further dilution to new public investors.
If all outstanding options and warrants, through December 31, 1998, were
exercised, the dilution per share to new public investors would be $6.86.
 
    In November 1998, Healtheon issued 7,683,341 shares of Series A convertible
preferred stock for $46.1 million in cash proceeds at a purchase price of $6.00
per share. In December 1998, Healtheon issued to a customer a warrant to
purchase 500,000 shares of common stock with an exercise price of $10.40 per
share. In January 1999, Healtheon issued 1,833,333 shares of common stock to
SmithKline Labs in connection with a December 1998 asset purchase agreement.
 
    On October 20, 1998, Healtheon offered to reprice options granted from July
1998 through October 1998. Under this repricing, option holders could surrender
their original option in exchange for a new option with a new vesting start date
and an exercise price of $3.55 per share. Options for a total of 2,057,950
shares were canceled and reissued. On December 14, 1998, 455,000 shares of
common stock issued in July 1998 pursuant to restricted stock purchase
agreements were repurchased.
 
                                       17
<PAGE>
                      SELECTED CONSOLIDATED FINANCIAL DATA
 
    The following selected consolidated financial data should be read in
conjunction with "Management's Discussion and Analysis of Financial Condition
and Results of Operations" and with the Consolidated Financial Statements and
Notes thereto, which are included elsewhere in this prospectus. In May 1998,
Healtheon acquired ActaMed in a transaction accounted for as a pooling of
interests. All financial information has been restated to reflect the combined
operations of Healtheon and ActaMed. The consolidated statements of operations
data for the three-year period ended December 31, 1997 and the consolidated
balance sheet data at December 31, 1996 and 1997 are derived from, and are
qualified by reference to, the audited Consolidated Financial Statements
included elsewhere in this prospectus. The consolidated statements of operations
data for the two-year period ended December 31, 1994 and the consolidated
balance sheet data at December 31, 1993, 1994 and 1995 are derived from, and are
qualified by reference to, audited Consolidated Financial Statements that are
not included in this prospectus. The consolidated statements of operations and
balance sheet data as of and for the years ended December 31, 1993, 1994 and
1995 are derived solely from the ActaMed statements of operations and balance
sheets for such periods because Healtheon did not commence operations until
January 1996. See Notes 1 and 2 of Notes to Consolidated Financial Statements
for a discussion of the accounting for the acquisition of ActaMed. The
statements of operations data for the nine-month period ended September 30, 1997
and 1998 and the balance sheet data as of September 30, 1998 are derived from
unaudited financial statements included elsewhere in this prospectus and, in the
opinion of Healtheon's management, include all adjustments, consisting only of
normal recurring adjustments, which are necessary for a fair presentation of the
results of operations for this period. Historical operating results are not
necessarily indicative of results in the future, and the results for interim
periods are not necessarily indicative of the results that may be expected for
the entire year. Revenue from services to related parties consists of revenue
from UnitedHealth Group and SmithKline Labs, customers that are also significant
stockholders of Healtheon. See Note 1 of Notes to Consolidated Financial
Statements for an explanation of the determination of the shares used in
computing basic and diluted net loss per common share.
 
<TABLE>
<CAPTION>
                                                                                                        NINE MONTHS ENDED
                                                              YEARS ENDED DECEMBER 31,                    SEPTEMBER 30,
                                                -----------------------------------------------------  --------------------
                                                  1993       1994       1995       1996       1997       1997       1998
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
                                                                   (IN THOUSANDS, EXCEPT PER SHARE DATA)   (UNAUDITED)
<S>                                             <C>        <C>        <C>        <C>        <C>        <C>        <C>
CONSOLIDATED STATEMENTS OF OPERATIONS DATA:
Revenue:
  Services....................................  $      --  $     190  $     458  $   1,795  $   4,301  $   1,216  $  18,326
  Services to related parties.................         --         --         --      4,237      7,309      5,199     14,320
  Software licenses...........................         --         --      1,717      4,981      1,780        585        585
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
  Total revenue...............................         --        190      2,175     11,013     13,390      7,000     33,231
Operating costs and expenses:
  Cost of revenue:
    Cost of services..........................         --        507      1,573      1,648      4,011      1,080     18,688
    Cost of services to related parties.......         --         --         --      4,919      6,536      4,648     13,206
    Cost of software licenses.................         --         --        343        160         --         --         --
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
  Total cost of revenue.......................         --        507      1,916      6,727     10,547      5,728     31,894
  Development and engineering expense.........      1,002      1,863      2,446      8,596     12,986      9,681     13,036
  Sales, general and administrative expense...        769        938      1,749      9,042     11,031      7,477     17,041
  Amortization of intangible assets...........         --         --         --      3,189      4,249      3,187      6,703
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
  Total operating costs and expenses..........      1,771      3,308      6,111     27,554     38,813     26,073     68,674
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
Loss from operations..........................     (1,771)    (3,118)    (3,936)   (16,541)   (25,423)   (19,073)   (35,443)
Interest income...............................          5        172        208        539        611        359        834
Interest expense..............................       (117)       (57)        (6)       (56)      (323)      (177)      (361)
Dividends on ActaMed's convertible redeemable
  preferred stock.............................         --         --         --     (2,548)    (2,870)    (2,382)      (890)
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
Net loss......................................     (1,883)    (3,003)    (3,734)   (18,606)   (28,005)   (21,273)   (35,860)
Dividends on ActaMed's convertible redeemable
  preferred stock.............................         --       (423)      (724)        --         --         --         --
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
Net loss applicable to common stockholders....  $  (1,883) $  (3,426) $  (4,458) $ (18,606) $ (28,005) $ (21,273) $ (35,860)
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
Basic and diluted net loss per common share...                        $    (.85) $   (2.83) $   (3.88) $   (3.03) $   (1.24)
Weighted-average shares outstanding used in
  computing basic and diluted net loss per
  common share................................                            5,246      6,583      7,223      7,019     28,934
Pro forma basic and diluted net loss per
  common share (unaudited)....................                                              $    (.56)            $    (.74)
  Shares used in computing pro forma basic and
   diluted net loss per common share
   (unaudited)................................                                                 44,715                47,263
</TABLE>
 
                                       18
<PAGE>
 
<TABLE>
<CAPTION>
                                                                                        DECEMBER 31,
                                                                        --------------------------------------------
                                                                         1993     1994     1995      1996     1997
                                                                        -------  -------  -------  --------  -------
                                                                                                                      SEPTEMBER 30,
                                                                                                                          1998
                                                                                                                      -------------
                                                                                              (IN THOUSANDS)           (UNAUDITED)
<S>                                                                     <C>      <C>      <C>      <C>       <C>      <C>
CONSOLIDATED BALANCE SHEET DATA:
Cash, cash equivalents and short-term investments.....................  $    74  $ 4,186  $ 9,386  $  7,539  $21,804     $ 5,392
Working capital (deficit).............................................   (1,737)   4,226    7,244     2,505   14,790      (6,055)
Total assets..........................................................      899    5,379   10,801    34,407   53,747      50,271
Long-term obligations, net of current portion.........................      159       63       --     1,210      932       1,714
Convertible redeemable preferred stock................................       --    7,919   16,029    39,578   50,948          --
Stockholders' equity (net capital deficiency).........................   (1,335)  (2,838)  (7,697)  (14,553)  (9,930)     30,226
</TABLE>
 
                                       19
<PAGE>
                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                 FINANCIAL CONDITION AND RESULTS OF OPERATIONS
 
    THE FOLLOWING DISCUSSION SHOULD BE READ IN CONJUNCTION WITH THE CONSOLIDATED
FINANCIAL STATEMENTS AND NOTES THERETO INCLUDED ELSEWHERE IN THIS PROSPECTUS.
THE FOLLOWING DISCUSSION CONTAINS FORWARD-LOOKING STATEMENTS THAT INVOLVE RISKS
AND UNCERTAINTIES. HEALTHEON'S ACTUAL RESULTS COULD DIFFER MATERIALLY FROM THE
RESULTS CONTEMPLATED BY THESE FORWARD-LOOKING STATEMENTS AS A RESULT OF CERTAIN
FACTORS, INCLUDING THOSE DISCUSSED BELOW AND ELSEWHERE IN THIS PROSPECTUS.
 
OVERVIEW
 
    Healtheon is pioneering the use of the Internet to simplify workflows,
decrease costs and improve the quality of patient care throughout the healthcare
industry. Healtheon's VHN Solution enables the secure exchange of information
among a wide array of disparate healthcare information systems and provides a
framework for a broad range of healthcare transactions.
 
    Healtheon was incorporated in December 1995, commenced operations in January
1996 and until late 1997 had not recognized substantial revenue and was
considered to be in the development stage. In May 1998, Healtheon acquired
ActaMed, which was incorporated in 1992. The acquisition of ActaMed was
accounted for as a pooling of interests. The financial information presented
reflects the combined financial position and operations of Healtheon and ActaMed
for all dates and periods presented. Healtheon's limited revenue to date has
been derived primarily from proprietary non-Internet network services offered by
ActaMed and from management and operation of customers' information technology,
or "IT," infrastructure. In March 1996, ActaMed acquired EDI Services, Inc., or
"EDI," a wholly-owned subsidiary of UnitedHealth Group, in a transaction
accounted for as a purchase. Accordingly, the operations of EDI are included in
Healtheon's consolidated statements of operations beginning in March 1996. In
August 1998, Healtheon acquired substantially all of the assets of Metis, LLC, a
leading consulting, design and development firm focused on Internet and
intranet-based solutions for medical centers and integrated delivery networks.
In connection with this acquisition, Healtheon issued 1,600,000 shares of its
common stock, of which 476,548 shares will be issued to certain employees under
restricted stock purchase agreements subject to a lapsing right of repurchase,
at Healtheon's option, over the agreements' respective vesting periods. Of these
shares, 200,000 shares are held in escrow to secure certain indemnification
obligations. The Metis acquisition was treated as a tax-free reorganization and
accounted for as a purchase.
 
    Healtheon earns revenue from services and services to related parties, which
include providing access to its network-based services, including fixed fee and
transaction-based services, and performing development and consulting services,
and from licensing software. Revenue from services to related parties consists
of services provided to UnitedHealth Group under a Services and License
Agreement between ActaMed and UnitedHealth Group dated April 4, 1996, or the
"UnitedHealth Group Agreement," and services provided to SmithKline Labs under a
Services Agreement between ActaMed and SmithKline Labs dated December 31, 1997,
or the "Services Agreement." Customers may purchase some or all of the
Healtheon's applications and services and the customer relationship may evolve
from utilizing development and consulting services to utilizing transaction and
subscription-based services. Healtheon earns network-based services revenue from
fixed fee subscription arrangements, which revenue is recognized ratably over
the term of the applicable agreement, or revenue from arrangements that are
priced on a per-transaction or per-user basis, which revenue is recognized as
the services are performed. Revenue from development projects is recognized on a
percentage-of-completion basis or as services are performed, depending on the
terms of the contract. Revenue from consulting services is recognized as the
services are performed. Cash received in excess of revenue recognized relating
to these services has been recorded as deferred revenue. As of September 30,
1998, Healtheon had deferred revenue of approximately $4.4 million.
 
    The UnitedHealth Group Agreement has a five year term; however, the
agreement provides that two years after the date of the agreement, April 4,
1998, the parties will agree on new prices that they agree are
 
                                       20
<PAGE>
competitive with the marketplace. Healtheon and UnitedHealth Group are
negotiating such new prices, and Healtheon anticipates that the new prices will
reduce the rates paid by UnitedHealth Group. The Services Agreement with
SmithKline Labs also has a five year term, but provides that the parties will
negotiate new rates as of January 1, 2001 and each two year period after that
date. Under the Services Agreement, the renegotiated rates must be competitive
with the marketplace and must be no higher than the lowest fees charged by
Healtheon to similarly situated customers.
 
    In December 1998, Healtheon agreed to purchase, and in January 1999,
Healtheon purchased certain assets used by SmithKline Labs to provide laboratory
results delivery services in exchange for $2.0 million in cash and 1,833,333
shares of Healtheon's common stock. Healtheon and SmithKline Labs entered into a
related services agreement under which Healtheon will provide certain electronic
laboratory results delivery services to approximately 20,000 provider sites, in
addition to the sites currently served through the SCAN service. The services
agreement has a five year term.
 
    Healtheon recognizes software license revenue in accordance with the
American Institute of Certified Public Accountants' Statement of Position 97-2.
ActaMed entered into a national marketing and licensing agreement with
International Business Machines Corporation, "IBM," in 1995 that granted IBM a
nonexclusive, nontransferable right to market ActaMed's software and services
for a total of $6.3 million. For the years ended December 31, 1995, 1996 and
1997, approximately $1.7 million, $3.4 million and $1.2 million of this amount
was recognized as software license revenue upon delivery of the software. No
software license revenue was recognized under this agreement for the nine months
ended September 30, 1997 or 1998.
 
    In December 1996, ActaMed entered into a new agreement, or the "License," to
license its newly granted patent to IBM. As part of the License, IBM agreed to
pay ActaMed $4.8 million over a four-year period, $1.0 million in December 1996
and the remaining balance in 48 equal monthly installments commencing in January
1997. Additionally, in conjunction with the License, IBM received a five-year
warrant to purchase 282,522 shares of Healtheon's common stock at a price of
$7.97 per share. Because of the extended payment terms and ActaMed's contentious
relationship with IBM, ActaMed concluded that the license fee was not assured of
collection and, accordingly, is recognizing this revenue as the proceeds are
collected. For the years ended December 31, 1996 and 1997 and the nine months
ended September 30, 1997 and 1998, Healtheon recognized revenue from the License
of $1.0 million, $.8 million, $.6 million and $.6 million. At December 31, 1997,
amounts due from IBM of $.7 million and $1.7 million were included in accounts
receivable and other assets. At September 30, 1998, amounts due from IBM of $.8
million and $1.1 million were included in accounts receivable and other assets.
Deferred revenue at December 31, 1996 and 1997 and September 30, 1998 included
$3.1 million, $2.3 million and $1.8 million related to the License.
 
    Healtheon does not expect that it will earn a material amount of revenue
from software licenses in the foreseeable future.
 
    Healtheon has developed strategic relationships with healthcare industry
leaders, including UnitedHealth Group, SmithKline Labs, Brown & Toland and Beech
Street. These four companies each accounted for over 10%, and together accounted
for approximately 90%, of Healtheon's total revenue for the nine months ended
September 30, 1998 and UnitedHealth Group and SmithKline Labs accounted for all
of Healtheon's revenue from services to related parties. Healtheon expects that
a small number of customers will continue to account for a substantial portion
of Healtheon's revenue for the foreseeable future. The loss of one or more of
Healtheon's significant customers, or a decline in volume of business generated
by such customers, could have a material adverse effect on Healtheon's business,
financial condition and results of operations.
 
    Cost of services and cost of services to related parties consist of costs
related to services Healtheon provides to customers and costs associated with
the operation and maintenance of Healtheon's networks. These costs include
salaries and related expenses for consulting and development personnel, network
operations personnel, customer support personnel, telecommunication costs,
depreciation and maintenance
 
                                       21
<PAGE>
of network equipment, amortization of certain intangible assets, a portion of
facilities expenses and leased personnel and facilities costs. Cost of software
licenses consists primarily of expenses related to royalties and sublicensing
fees. Given Healtheon's limited operating history, changes in revenue mix,
limited history of Internet-based network services, recent investments in
personnel, amortization of infrastructure investments and evolving business
model, Healtheon believes that analysis of historical cost of revenue as a
percentage of revenue is not meaningful. Healtheon anticipates that its total
cost of revenue will increase in absolute dollars in the future.
 
    Development and engineering expense, which excludes development expenses
that are included in cost of revenue, consists primarily of salaries and related
expenses associated with the development of applications and services and
includes compensation paid to engineering personnel, fees to outside contractors
and consultants, a portion of facilities expenses and the depreciation and
amortization of capital equipment used in the development process. Healtheon
believes its success is partially dependent upon its ability to introduce new
applications in several healthcare markets in a relatively short period of time.
Accordingly, Healtheon intends to continue recruiting and hiring experienced
engineering personnel and to continue making other investments in development
and engineering. Healtheon expects that development and engineering expenses
will continue to increase in absolute dollars. Currently, all development and
engineering costs are expensed as incurred.
 
    Sales, general and administrative expense consists primarily of salaries and
related expenses for sales, account management, marketing, administrative,
finance, legal, human resources and executive personnel, commissions, costs and
expenses for marketing programs and trade shows, fees for professional services
and costs of accounting and internal control systems to support Healtheon's
operations. Healtheon anticipates that sales, general and administrative expense
will continue to increase in absolute dollars as it adds sales, marketing and
administrative personnel, increases its marketing and promotional activities and
incurs costs related to being a public company, such as directors' and officers'
liability insurance premiums and professional fees.
 
    Healtheon's business model is still in an emerging stage, and revenue and
income potential from Healtheon's business is unproven. Moreover, Healtheon's
limited operating history under its current business model makes an evaluation
of Healtheon and its prospects difficult; investors should not use Healtheon's
past results as a basis to predict future performance. Healtheon has incurred
net losses since inception and, as of September 30, 1998, had an accumulated
deficit of $85.2 million. Healtheon intends to continue investing heavily in
acquisitions, infrastructure development, application development and sales and
marketing. As a result, Healtheon expects to incur substantial operating losses
at least through 1999. There can be no assurance that Healtheon will achieve
significant revenue or profitability or, if significant revenue or profitability
are achieved, that they can be sustained.
 
                                       22
<PAGE>
RESULTS OF OPERATIONS
 
    The following table sets forth certain data expressed as a percentage of
total revenue for the periods indicated.
 
<TABLE>
<CAPTION>
                                                                                                                 NINE MONTHS ENDED
                                                                                  YEAR ENDED DECEMBER 31,          SEPTEMBER 30,
                                                                               ------------------------------   -------------------
                                                                                 1995       1996       1997       1997       1998
                                                                               --------   --------   --------   --------   --------
                                                                                                                    (UNAUDITED)
<S>                                                                            <C>        <C>        <C>        <C>        <C>
Revenue:
  Services...................................................................     21.1%      16.3%      32.1%      17.4%      55.1%
  Services to related parties(1).............................................       --       38.5       54.6       74.3       43.1
  Software licenses..........................................................     78.9       45.2       13.3        8.3        1.8
                                                                               --------   --------   --------   --------   --------
  Total revenue..............................................................    100.0      100.0      100.0      100.0      100.0
 
Operating costs and expenses:
  Cost of revenue:
    Cost of services.........................................................     72.3       15.0       30.0       15.4       56.2
    Cost of services to related parties......................................       --       44.7       48.8       66.4       39.8
    Cost of software licenses................................................     15.8        1.5         --         --         --
                                                                               --------   --------   --------   --------   --------
    Total cost of revenue....................................................     88.1       61.2       78.8       81.8       96.0
  Development and engineering................................................    112.5       78.0       97.0      138.4       39.2
  Sales, general and administrative..........................................     80.4       82.1       82.4      106.8       51.3
  Amortization of intangible assets..........................................       --       29.0       31.7       45.5       20.2
                                                                               --------   --------   --------   --------   --------
  Total operating costs and expenses.........................................    281.0      250.3      289.9      372.5      206.7
                                                                               --------   --------   --------   --------   --------
Loss from operations.........................................................   (181.0)    (150.3)    (189.9)    (272.5)    (106.7)
Interest income..............................................................      9.6        4.9        4.6        5.1        2.5
Interest expense.............................................................     (0.3)      (0.5)      (2.4)      (2.5)      (1.1)
Dividends on ActaMed's convertible redeemable preferred stock................       --      (23.1)     (21.4)     (34.0)      (2.7)
                                                                               --------   --------   --------   --------   --------
Net loss.....................................................................   (171.7)    (169.0)    (209.1)    (303.9)    (108.0)
Dividends on ActaMed's convertible redeemable preferred stock................    (33.3)        --         --         --         --
                                                                               --------   --------   --------   --------   --------
Net loss applicable to common stockholders...................................   (205.0)%   (169.0)%   (209.1)%   (303.9)%   (108.0)%
                                                                               --------   --------   --------   --------   --------
                                                                               --------   --------   --------   --------   --------
</TABLE>
 
- ---------
 
(1) Revenue from services to related parties consists of revenue from
    UnitedHealth Group and SmithKline Labs, customers that are also significant
    stockholders of Healtheon.
 
    NINE MONTHS ENDED SEPTEMBER 30, 1998 AND 1997
 
    REVENUE.  Total revenue increased to $33.2 million in the first nine months
of 1998 from $7.0 million in the same period of 1997. Revenue from services
increased to $18.3 million in the first nine months of 1998 from $1.2 million in
the same period in 1997. The significant increase in revenue was due principally
to new contracts with Brown & Toland and Beech Street for the management and
operation of their IT infrastructure beginning in late 1997. To provide these
services, Healtheon utilizes its own personnel, certain outside contractors and
certain personnel and facilities of the customers that are leased to Healtheon.
The cost of these leased customer personnel and facilities are included as part
of the total costs of the IT and development services that Healtheon billed to
the customers. In the first nine months of 1998, Healtheon recognized revenue
for IT services of $10.9 million, which included Healtheon's costs of leased
personnel and facilities of $8.8 million. In addition, Healtheon recognized
revenue of approximately $4.8 million for development services in the same
period.
 
                                       23
<PAGE>
    Revenue from services to related parties increased to $14.3 million in the
first nine months of 1998 from $5.2 million in the same period of 1997 primarily
due to a new contract with SmithKline Labs in December 1997 to service its SCAN
laboratory test order and results service. Revenue from software licenses was
unchanged in the first nine months of 1998 from the same period in 1997.
Healtheon expects that revenue from software licenses will continue to decline
in future periods as a percentage of total revenue.
 
    COST OF REVENUE.  Total cost of revenue increased to $31.9 million in the
first nine months of 1998 from $5.7 million in the same period of 1997. Cost of
services increased to $18.7 million in the first nine months of 1998 from $1.1
million in the same period in 1997. This increase includes $8.8 million related
to costs of leased personnel and facilities utilized to provide IT services and
$4.8 million related to development services to support the Brown & Toland and
Beech Street contracts. The remaining increase resulted from increased personnel
and expansion of our network infrastructure to support current customers and
future business activities. Healtheon believes its margin on services revenue
will continue to be negative until its revenue from other than IT and
development services increases. Healtheon had no cost of software licenses
revenue in the first nine months of 1998 or in the comparable period of 1997.
 
    Cost of services to related parties increased to $13.2 million in the first
nine months of 1998 from $4.6 million in the same period of 1997. This increase
resulted from higher personnel and network operations costs necessary to support
increased transactions from Healtheon's SCAN services.
 
    DEVELOPMENT AND ENGINEERING.  Development and engineering expense, which
excludes development expenses that are included in cost of revenue, increased to
$13.0 million in the first nine months of 1998 from $9.7 million in the same
period of 1997. The increase in development and engineering expenses was caused
by a significant increase in the number of engineers engaged in the development
of Healtheon's applications and services.
 
    SALES, GENERAL AND ADMINISTRATIVE.  Sales, general and administrative
expense increased to $17.0 million in the first nine months of 1998 from $7.5
million in the same period of 1997. The increase resulted primarily from
approximately $6.7 million in salaries and related support costs for added sales
personnel and executive management, approximately $.8 million of costs related
to the merger with ActaMed and from the amortization of deferred compensation.
Healtheon recorded deferred compensation of $4.1 million during the first nine
months of 1998, and recorded $2.1 million of amortization of deferred
compensation in this period. Deferred compensation represents the difference
between the purchase or exercise price of certain restricted stock and stock
option grants and the deemed fair value of Healtheon's common stock at the time
of those grants. The deferred compensation balance of $4.2 million at September
30, 1998 will be amortized over the vesting period, generally four years, of the
option or restricted stock grants. Amortization is estimated to total $.9
million for the last three months of 1998, $2.1 million for 1999, $.9 million
for 2000, and $.3 million for 2001. From October 1998 through February 1999,
Healtheon repriced certain stock options and restricted stock purchases and
granted additional stock options. Healtheon estimates that it will record
approximately $9.7 million of additional deferred compensation as a result of
the repricing and additional grants.
 
    AMORTIZATION OF INTANGIBLE ASSETS.  Amortization of intangible assets was
$6.7 million in the first nine months of 1998 and $3.2 million in the same
period of 1997. This amortization relates to the acquisition of EDI in March
1996 from UnitedHealth Group and certain intangible assets related to SCAN
acquired from SmithKline Labs in December 1997 and acquisition of Metis, LLC in
August 1998. Although the Services and License Agreement entered into with
UnitedHealth Group in connection with the acquisition of EDI has a five year
term, Healtheon determined that a three year amortization period was appropriate
for the EDI-related assets due to the price renegotiation required by such
agreement, the probability that the purchased technology and software would be
replaced within three years and the uncertain profitability of the agreement
after the price renegotiation. Similarly, although the Services Agreement
entered into with SmithKline Labs in connection with the acquisition of the
SCAN-related assets has a five year term,
 
                                       24
<PAGE>
Healtheon determined that a three year amortization period was appropriate for
the SCAN related assets due to the price renegotiation required by such
agreement, the probability that the purchased technology and software would be
replaced within three years and the uncertain profitability of the agreement
after the price renegotiation. There can be no assurance that Healtheon's
services to UnitedHealth Group and SmithKline Labs will be profitable after the
price renegotiations required by the agreements, particularly given the
uncertainty of future rates and volumes under those agreements. Healtheon
determined that the acquisition of Metis, LLC included the value of an assembled
workforce, which will be amortized over two years. The other intangible assets
related to the acquisition of Metis, LLC were determined to have a three-year
life. At September 30, 1998, a total of $23.7 million remained to be amortized,
and the amortization charges for the three months ending December 31, 1998 and
for the years ending 1999 and 2000 are estimated to be $3.9 million, $10.1
million and $8.2 million, respectively, assuming no impairment of the remaining
unamortized intangible asset balances. See Notes 2 and 3 of Notes to
Consolidated Financial Statements.
 
    INTEREST INCOME AND EXPENSE.  Interest income has been derived primarily
from cash investments, and increased to $.8 million in the first nine months of
1998 compared to $.4 million in the same period of 1997. The increase resulted
from Healtheon's $25.0 million preferred stock financing in October 1997.
Interest expense results from Healtheon's borrowings and from capitalized lease
obligations for equipment purchases.
 
    DIVIDENDS ON ACTAMED'S CONVERTIBLE REDEEMABLE PREFERRED STOCK.  As dividends
on ActaMed's convertible redeemable preferred stock were cumulative whether
declared or not, ActaMed accrued such dividends on a quarterly basis. Dividends
of $2.4 million and $.9 million are shown as a charge against income in the
consolidated statement of operations for the first nine months of 1997 and 1998,
respectively. None of the dividends were paid, and, in conjunction with
approving the acquisition of ActaMed by Healtheon, the preferred stockholders
waived their right to receive such dividends, which totaled $7.5 million at the
time of the acquisition, and received an aggregate of 17,252,408 shares of
Healtheon common stock in exchange for their ActaMed preferred stock.
 
    YEARS ENDED DECEMBER 31, 1997, 1996 AND 1995
 
    REVENUE.  Total revenue increased to $13.4 million in 1997 from $11.0
million in 1996 and $2.2 million in 1995. Revenue from services increased to
$4.3 million in 1997 from $1.8 million in 1996 and $.5 million in 1995. The
increase is due primarily to the contract with Brown & Toland, which began in
October 1997. In 1997, Healtheon recognized $2.1 million of revenue for IT
services under this contract, which included costs of leased personnel and
facilities of $1.9 million.
 
    Revenue from services to related parties increased to $7.3 million in 1997
from $4.2 million in 1996. There was no revenue from services to related parties
in 1995. Healtheon's acquisition of ProviderLink in March 1996 from UnitedHealth
Group accounts for substantially all of the related party revenue in 1996 and
the 1997 increase is substantially due to recording a full year of revenue in
1997 compared to nine months in 1996.
 
    Revenue from software licenses was $1.8 million, $5.0 million and $1.7
million in 1997, 1996 and 1995. Substantially all of this revenue was derived
from licensing agreements with IBM. The full amount of revenue to be derived
from one of these agreements had been recognized by the end of 1997. Revenue
will continue to be recognized under a second agreement through December 2000.
 
    COST OF REVENUE.  Cost of services was $4.0 million, $1.6 million and $1.6
million in 1997, 1996 and 1995. The increase from 1996 to 1997 was primarily due
to the $1.9 million cost related to the leased personnel and facilities under
the Brown & Toland contract. Cost of services to related parties increased to
$6.5 million in
 
                                       25
<PAGE>
1997 from $4.9 million in 1996. This increase was primarily due to recording a
full year of costs related to ProviderLink in 1997 compared to only nine months
in 1996. Cost of software licenses in 1996 and 1995 related principally to
royalties and sublicense fees paid by Healtheon.
 
    DEVELOPMENT AND ENGINEERING.  Development and engineering expense, which
excludes development expenses that are included in cost of revenue, was $13.0
million in 1997 compared to $8.6 million in 1996 and $2.4 million in 1995. The
increase in development and engineering expense was caused by a significant
increase in the number of engineers engaged in the development of Healtheon's
applications and services.
 
    SALES, GENERAL AND ADMINISTRATIVE.  Sales, general and administrative
expense was $11.0 million in 1997, compared to $9.0 million in 1996 and $1.7
million in 1995. The increase resulted primarily from the addition of sales
personnel and executive management, which caused related salaries to increase by
approximately $1.4 million in 1997 from 1996, and from the amortization of
deferred compensation. Healtheon recorded deferred compensation of $2.7 million
during 1997 and recorded $.6 million of amortization of deferred compensation in
1997.
 
    AMORTIZATION OF INTANGIBLE ASSETS.  Amortization of acquisition-related
costs including intangible assets was $4.2 million in 1997 and $3.2 million in
1996. This amortization relates to the acquisition of EDI in March 1996.
 
    INTEREST INCOME AND EXPENSE.  Interest income was derived from cash
investments following Healtheon's issuance of preferred stock and imputed
interest on payments due from IBM beginning in early 1997. Interest expense
increased in 1997 as a result of bridge financing and bank borrowings of
Healtheon and from capitalized lease obligations for equipment purchases.
 
    INCOME TAXES.  At December 31, 1997, Healtheon had net operating loss
carryforwards for federal income tax purposes of $37.6 million and federal tax
credits of $.8 million, both expiring from 2009 through 2012. Of these net
operating losses, $16.7 million relates to a consolidated subsidiary. This loss
carryforward is available only to offset future taxable income of that
subsidiary. Because of the "change of ownership" provisions of the Internal
Revenue Code, a portion of Healtheon's net operating loss carryforwards and tax
credit carryforwards may be subject to an annual limitation regarding their
utilization against taxable income in future periods. Thus, a portion of these
carryforwards may expire before becoming available to reduce future income tax
liabilities.
 
QUARTERLY FINANCIAL RESULTS
 
    The following table presents Healtheon's operating results for each of the
seven quarters in the period ended September 30, 1998, as well as such data
expressed as a percentage of Healtheon's total revenue for the periods
indicated. The information for each of these quarters is unaudited and has been
prepared on the same basis as the audited consolidated financial statements
appearing elsewhere in this prospectus. In the opinion of management, all
necessary adjustments, consisting only of normal recurring adjustments, have
been included to present fairly the unaudited quarterly results. This data
should be read in conjunction with the Consolidated Financial Statements and the
Notes thereto appearing elsewhere in this prospectus. These operating results
are not indicative of the results of any future period.
 
                                       26
<PAGE>
 
<TABLE>
<CAPTION>
                                                                  THREE MONTHS ENDED
                            -----------------------------------------------------------------------------------------------
                             MARCH 31,     JUNE 30,      SEPT. 30,     DEC. 31,      MAR. 31,      JUNE 30,      SEPT. 30,
                               1997          1997          1997          1997          1998          1998          1998
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
                                                     (UNAUDITED, IN THOUSANDS EXCEPT PERCENTAGES)
<S>                         <C>           <C>           <C>           <C>           <C>           <C>           <C>
CONSOLIDATED STATEMENTS OF
  OPERATIONS DATA:
Revenue:
  Services................    $   239       $   417       $   560       $ 3,085       $ 4,903      $  5,990      $  7,433
  Services to related
   parties................      1,488         1,752         1,959         2,110         4,656         4,714         4,950
  Software licenses.......        195           195           195         1,195           195           195           195
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
      Total revenue.......      1,922         2,364         2,714         6,390         9,754        10,899        12,578
Operating costs and
  expenses:
  Cost of revenue:
    Cost of services......        213           385           482         2,931         5,088         5,682         7,918
    Cost of services to
     related parties......      1,633         1,496         1,519         1,888         2,860         4,457         5,889
    Cost of software
     licenses.............         --            --            --            --            --            --            --
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
      Total cost of
       revenue............      1,846         1,881         2,001         4,819         7,948        10,139        13,807
  Development and
   engineering............      3,247         3,162         3,272         3,305         3,919         4,413         4,704
  Sales, general and
   administrative.........      2,501         2,222         2,754         3,554         4,966         7,157         4,918
  Amortization of
   intangible assets......      1,062         1,062         1,063         1,062         1,949         1,989         2,765
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
      Total operating
       costs and
       expenses...........      8,656         8,327         9,090        12,740        18,782        23,698        26,194
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
Loss from operations......     (6,734)       (5,963)       (6,376)       (6,350)       (9,028)      (12,799)      (13,616)
Interest income...........        146           108           105           252           358           279           197
Interest expense..........        (50)          (78)          (49)         (146)         (116)         (135)         (110)
Dividends on ActaMed's
  convertible redeemable
  preferred stock.........       (783)         (823)         (776)         (488)         (890)           --            --
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
Net loss..................    $(7,421)      $(6,756)      $(7,096)      $(6,732)      $(9,676)     $(12,655)     $(13,529)
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
 
AS A PERCENTAGE OF
  REVENUE:
Revenue:
  Services................       12.4%         17.6%         20.6%         48.3%         50.3%         55.0%         59.1%
  Services to related
   parties................       77.4          74.1          72.2          33.0          47.7          43.3          39.4
  Software licenses.......       10.2           8.3           7.2          18.7           2.0           1.7           1.5
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
      Total revenue.......      100.0         100.0         100.0         100.0         100.0         100.0         100.0
Operating costs and
  expenses:
  Cost of revenue:
    Cost of services......       11.1          16.3          17.8          45.9          52.2          52.1          63.0
    Cost of services to
     related parties......       85.0          63.3          56.0          29.5          29.3          40.9          46.8
    Cost of software
     licenses.............         --            --            --            --            --            --            --
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
      Total cost of
       revenue............       96.1          79.6          73.8          75.4          81.5          93.0         109.8
  Development and
   engineering............      168.9         133.7         120.6          51.7          40.2          40.5          37.4
  Sales, general and
   administrative.........      130.1          94.0         101.5          55.6          50.9          65.7          39.1
  Amortization of
   intangible assets......       55.3          44.9          39.2          16.6          20.0          18.2          22.0
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
      Total operating
       costs and
       expenses...........      450.4         352.2         335.1         199.3         192.6         217.4         208.3
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
Loss from operations......     (350.4)       (252.2)       (235.1)        (99.3)        (92.6)       (117.4)       (108.3)
Interest income...........        7.6           4.6           3.9           3.9           3.7           2.6           1.6
Interest expense..........       (2.6)         (3.3)         (1.8)         (2.3)         (1.2)         (1.2)         (0.9)
Dividends on ActaMed's
  convertible redeemable
  preferred stock.........      (40.7)        (34.8)        (28.6)         (7.6)         (9.1)           --            --
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
Net loss..................     (386.1)%      (285.7)%      (261.6)%      (105.3)%       (99.2)%      (116.0)%      (107.6)%
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
                            -----------   -----------   -----------   -----------   -----------   -----------   -----------
</TABLE>
 
    Revenue has grown each quarter as demand for Healtheon's services has
increased. Cost of revenue increased in the quarter ended December 31, 1997 due
primarily to expenses related to the Brown & Toland contract, and in the
quarters ended March 31, June 30 and September 30, 1998 due primarily to
expenses related to the Beech Street and SmithKline Labs contracts. In addition,
in the quarter ended June 30, 1998,
 
                                       27
<PAGE>
total cost of revenue increased due in part to an increase in amortization of
capitalized internally developed software. This increase was due to the fact
that Healtheon evaluated the carrying value of the capitalized internally
developed software in light of the changes in operations resulting from the
acquisition of ActaMed by Healtheon. Healtheon determined that it expected no
future cash flows to be generated by this software and, accordingly, wrote off
the remaining unamortized balance of $.6 million. Development and engineering
expense increased in the quarters ended March 31, June 30 and September 30, 1998
due to a significant increase in personnel engaged in the development of
Healtheon's applications and services. Sales, general and administrative
expenses increased in each of the quarters ended September 30, 1997 through
September 30, 1998 due to increases in sales and executive personnel and due to
amortization of deferred compensation. In addition, Healtheon recorded
substantial professional fees related to the acquisition of ActaMed in the
quarter ended June 30, 1998.
 
    In October 1998, Healtheon withdrew its registration statement for its
initial public offering. Accordingly, in the fourth quarter of 1998, Healtheon
will record a charge of approximately $1.6 million related to the costs of the
withdrawn offering.
 
    Healtheon's quarterly revenue and operating results have varied in the past
and are likely to vary substantially in the future. Healtheon intends to
increase its marketing, sales, development and engineering, and administrative
activities and to increase other operating expenses as required to integrate the
operations, technologies and networks of recent and any future acquisitions and
expand its healthcare network infrastructure and operations. It is anticipated
that these expenses could significantly precede any revenue generated by the
increased spending. If Healtheon does not experience significantly increased
revenue from these efforts, Healtheon's business, financial condition and
results of operations could be materially and adversely affected. In addition,
Healtheon's expense levels are based in part on its expectations concerning
future revenue and are relatively fixed in the short-term. Consequently, if
Healtheon's revenue is below expectations in any period, Healtheon may not be
able to adjust its spending levels in a timely manner.
 
LIQUIDITY AND CAPITAL RESOURCES
 
    Healtheon has funded its operations since inception primarily through the
private placement of equity securities, through which it had raised net proceeds
of $60.1 million through September 30, 1998. Healtheon has also financed its
operations through equipment lease financing and bank borrowings. As of
September 30, 1998, Healtheon had outstanding equipment lease financing and bank
borrowings of $4.8 million. As of September 30, 1998, Healtheon had
approximately $5.4 million of cash, cash equivalents and short-term investments.
 
    Cash used in operating activities was $1.3 million in 1995, $9.6 million in
1996 and $16.4 million in 1997. The cash used during these periods was primarily
attributable to net losses of $3.7 million in 1995, $18.6 million in 1996 and
$28.0 million in 1997 offset in part by depreciation and amortization and
dividends on ActaMed's convertible redeemable preferred stock. These losses were
principally related to increased development and engineering expenses and sales,
general and administrative expenses. Cash used in operations in the first nine
months of 1998 was $13.9 million, reflecting a net loss partially offset by
depreciation and amortization expenses and increases in liabilities.
 
    Investments in property and equipment, excluding equipment acquired under
capital leases, and internally developed software were $.5 million, $3.0
million, $3.1 million and $5.1 million in 1995, 1996 and 1997, and the first
nine months of 1998. In 1997, Healtheon used $5.3 million of cash to purchase
short-term investments. During the first nine months of 1998, Healtheon
purchased an additional $4.3 million of short-term investments and realized $8.8
million in cash from maturities of its short-term investments. Healtheon had no
purchases or maturities of short-term investments in 1995, 1996, or the nine
months ended September 30, 1997.
 
                                       28
<PAGE>
    Cash provided by financing activities was $7.0 million, $11.1 million and
$34.6 million in 1995, 1996 and 1997 resulting primarily from net proceeds from
the sale of preferred stock and, to a lesser extent, from a bank line and bridge
note financing in 1997. Cash provided by financing activities for the first nine
months of 1998 was $3.2 million, primarily from the net proceeds from the sale
of preferred and common stock, partially offset by payments on line of credit
borrowings and capital lease obligations. In November 1998, Healtheon received
proceeds of $46.1 million from the sale of its Series A preferred stock.
 
    As of September 30, 1998, Healtheon did not have any material commitments
for capital expenditures. Healtheon's principal commitments at December 31, 1997
consisted of obligations of $14.4 million under operating leases and $2.2
million under capital leases. See Note 6 of Notes to Consolidated Financial
Statements.
 
    Healtheon currently anticipates that the net proceeds from the offering,
together with its available cash resources and credit facilities, will be
sufficient to meet its presently anticipated working capital, capital
expenditure and business expansion requirements for at least the next 12 months.
However, Healtheon may need to raise additional funds within the next 12 months
to support expansion, develop new or enhanced applications and services, respond
to competitive pressures, acquire complementary businesses or technologies or
take advantage of unanticipated opportunities. Healtheon's future liquidity and
capital requirements will depend upon numerous factors, including the success of
Healtheon's existing and new application and service offerings and competing
technological and market developments. Healtheon may be required to raise
additional funds through public or private financing, strategic relationships or
other arrangements. There can be no assurance that additional funding, if
needed, will be available on terms acceptable to Healtheon, or at all.
 
YEAR 2000 COMPLIANCE
 
    Many currently installed computer systems and software products are unable
to distinguish between twentieth century dates and twenty-first century dates.
As a result, many companies' software and computer systems may need to be
upgraded or replaced to comply with these "Year 2000" requirements. Healtheon's
business is dependent on the operation of numerous systems that could
potentially be impacted by Year 2000 related problems. Those systems include,
among others: hardware and software systems used by Healtheon to deliver
services to its customers, including Healtheon's proprietary software systems as
well as hardware and software supplied by third parties; communications
networks, such as the Internet and private intranets, which Healtheon depends on
to provide electronic transactions to its customers; the internal systems of
Healtheon's customers and suppliers; the hardware and software systems used
internally by Healtheon in the management of its business; and non-information
technology systems and services used by Healtheon in its business, such as
telephone systems and building systems.
 
    Healtheon has internally reviewed the proprietary software systems it uses
to deliver services to its customers. Although Healtheon believes that its
internally developed applications and systems are designed to be Year 2000
compliant, Healtheon utilizes third-party equipment and software that may not be
Year 2000 compliant. Also, two systems acquired by ActaMed, specifically SCAN
and ProviderLink, which together accounted for approximately 43% of Healtheon's
total revenue in the first nine months of 1998, will require modifications to
become Year 2000 compliant. Healtheon plans to release Year 2000 upgrades to
these systems in early 1999. Healtheon estimates the cost of these Year 2000
upgrades to be less than $1.0 million. In addition, Healtheon's SCAN product is
installed on approximately 4,650 Healtheon-owned workstations located in
provider offices. Many of these workstations are not Year 2000 compliant and
must be upgraded or replaced by Healtheon. Healtheon expects the costs of such
upgrades or replacements to be less than $1.0 million. However, Healtheon could
experience delays and cost overruns in the development of these upgrades, the
upgrades could contain defects and Healtheon could experience difficulties in
getting Healtheon's installed base of physicians to implement these upgrades in
a timely manner. If Healtheon experiences these or other difficulties in
developing and deploying its Year 2000 upgrades, revenues from SCAN and
ProviderLink could be significantly reduced, which could have a material adverse
effect on
 
                                       29
<PAGE>
Healtheon's business, financial condition and results of operations. Failure of
third-party or Healtheon equipment or software to operate properly with regard
to the Year 2000 and thereafter could require Healtheon to incur unanticipated
expenses to remedy any problems, which could have a material adverse effect on
Healtheon's business, financial condition and results of operations. In certain
of its agreements, Healtheon warrants that its applications and services are
Year 2000 compliant. Failure of Healtheon's applications and services to be Year
2000 compliant could result in the termination of these agreements or in
liability for damages, either of which could have a material adverse effect on
Healtheon's business, financial condition and results of operations. Healtheon
does not believe that its expenditures to upgrade its internal systems and
applications will have a material adverse effect on its business, financial
condition and results of operations.
 
    Furthermore, the success of Healtheon's efforts may depend on the success of
other healthcare participants in dealing with their Year 2000 issues. Many of
these organizations are not Year 2000 compliant, and the impact of widespread
customer failure on Healtheon's systems is difficult to determine. Customer
difficulties due to Year 2000 issues could interfere with healthcare
transactions or information, which might expose Healtheon to significant
potential liability. If client failures result in the failure of Healtheon
systems, Healtheon's business, financial condition and results of operations
would be materially adversely affected. Furthermore, the purchasing patterns of
these customers or potential customers may be affected by Year 2000 issues as
companies expend significant resources to become Year 2000 compliant. The costs
of becoming Year 2000 compliant for current or potential customers may result in
reduced funds being available to purchase and implement Healtheon's applications
and services.
 
    Healtheon, with the assistance of an independent consulting firm
specializing in Year 2000 issues, is conducting a formal assessment of its Year
2000 exposure in order to determine what steps beyond those identified by
Healtheon's internal review may be advisable. Healtheon expects to complete this
assessment in the first quarter of 1999. Healtheon does not presently have a
contingency plan for handling Year 2000 problems that are not detected and
corrected prior to their occurrence. Any failure of Healtheon to address any
unforeseen Year 2000 issue could adversely affect Healtheon's business,
financial condition and results of operations.
 
RECENT ACCOUNTING PRONOUNCEMENTS
 
    In June 1997, the Financial Accounting Standards Board, or "FASB," issued
Statement of Financial Accounting Standards, or "SFAS," No. 131, "Disclosures
about Segments of an Enterprise and Related Information." Healtheon is required
to adopt SFAS No. 131 for the year ending December 31, 1998. SFAS No. 131
requires disclosure of certain information regarding operating segments,
products and services, geographic areas of operation and major customers.
Adoption of SFAS No. 131 is expected to have no material impact on Healtheon's
financial condition or results of operations.
 
    In June 1998, the FASB issued SFAS No. 133, "Accounting for Derivative
Instruments and Hedging Activities." Healtheon is required to adopt SFAS No. 133
for the year ending December 31, 2000. SFAS No. 133 establishes methods of
accounting for derivative financial instruments and hedging activities related
to those instruments as well as other hedging activities. Because Healtheon
currently holds no derivative financial instruments and does not currently
engage in hedging activities, adoption of SFAS No. 133 is expected to have no
material impact on Healtheon's financial condition or results of operations.
 
    In March 1998, the American Institute of Certified Public Accountants issued
Statement of Position, or "SOP," 98-1, "Accounting for the Costs of Computer
Software Developed or Obtained for Internal Use." SOP 98-1 requires that
entities capitalize certain costs related to internal-use software once certain
criteria have been met. Healtheon is required to implement SOP 98-1 for the year
ending December 31, 1999. Adoption of SOP 98-1 is expected to have no material
impact on Healtheon's financial condition or results of operations.
 
                                       30
<PAGE>
                                    BUSINESS
 
INDUSTRY BACKGROUND
 
    GROWTH OF INTERNET COMMERCE AND FUNCTIONALITY
 
    The Internet's open architecture, universal accessibility and growing
acceptance make it an increasingly important environment for
business-to-business and business-to-consumer interaction. Use of the Internet
is rapidly expanding from simple information publishing, messaging, and data
gathering to critical business transactions and confidential communications. For
many industries, the Internet is connecting previously disconnected business
processes and allowing companies to automate workflows, lower distribution costs
and extend their market reach. Healtheon believes the healthcare industry,
because of its size, fragmentation and extreme dependence on information
exchange, is particularly well suited to benefit from greater use of the
Internet.
 
    NEED FOR REDUCED HEALTHCARE COSTS AND IMPROVED QUALITY OF CARE
 
    According to the Health Insurance Association of America, healthcare is the
largest single sector of the U.S. economy, consuming approximately $1 trillion
annually, or 14% of the country's gross domestic product. The healthcare
industry consists of a complex mix of participants, which includes:
 
    - "Providers" -- physicians, medical practice groups, hospitals and other
      organizations that deliver medical care;
 
    - "Payers" -- the government agencies, insurance companies, managed care
      organizations and other enterprises that pay the bills for healthcare;
 
    - "Suppliers" -- clinical laboratories, pharmaceutical companies, and other
      groups that provide tests, drugs, x-rays and other services; and
 
    - "Consumers" -- individual patients who receive medical care, and the
      government agencies, employers and other organizations that represent
      groups of individuals.
 
    All healthcare participants rely heavily upon information to perform their
roles in the industry. Individuals compare medical plans, choose physicians and
submit claims for reimbursement. Employers select health plans, determine
benefit levels, enroll employees and maintain employee eligibility data.
Providers verify patient eligibility, collect patient histories, order
diagnostic tests and x-rays, receive and interpret test results, render
diagnoses, make referrals and submit claims to payers. Payers manage referrals,
establish medical care protocols and reimbursement policies and process claims.
Suppliers analyze and process patient samples or tests, provide results, fill
prescriptions and submit claims for reimbursement. These and many other
healthcare transactions are also highly dependent on information, and each
participant is dependent on the others for parts of that information. In sum,
the finance and delivery of healthcare requires that consistent, accurate
information be shared confidentially across a large and fragmented industry.
 
    Inefficiencies within the healthcare system consume enormous amounts of
time, resources and dollars. It is estimated that over $250 billion, or 25% of
every healthcare dollar, are wasted through the delivery of unnecessary care,
performance of redundant tests and procedures, and excessive administrative
costs. Healtheon believes much of this inefficiency and waste is a direct result
of poor information exchange among healthcare participants. Consumers do not
have easy access to the detailed information they need to compare health plans,
select physicians, or manage their own healthcare and benefits. Providers often
lack timely access to relevant patient information, and this lack of information
causes them to prescribe unnecessary tests or procedures and hinders their
ability to diagnose and treat patients. Providers and suppliers often rely on
manual processes to share data, and errors and information bottlenecks resulting
from these manual processes cause delays in determining eligibility, approving
referrals, reporting test
 
                                       31
<PAGE>
results and paying claims. These inefficiencies contribute to the rising cost of
healthcare. As a result, the government and other purchasers of healthcare have
increasingly placed pressure on the healthcare industry to improve the
cost-effectiveness of healthcare while maintaining the quality of care.
 
    LIMITATIONS OF TRADITIONAL FUNCTIONAL APPROACH TO HEALTHCARE INFORMATION
     MANAGEMENT
 
    The unique characteristics of the healthcare industry have limited the scope
of previous technology solutions. The sheer number of participants, the
complexity of healthcare transactions, and pervasive concerns about
confidentiality have precluded any comprehensive solution that would deliver
connectivity and automated workflows across the entire industry. Healthcare
organizations and their traditional technology vendors have focused on
automating discrete business processes, such as billing and scheduling for
physicians, or claims processing for hospitals and payers. As a result, the
industry currently uses thousands of different mainframe and client/server
systems that lack cross-platform compatibility. While these legacy systems serve
the narrow functions for which they were designed, they have compounded the
industry's connectivity problems. Information the industry needs to share is
trapped in isolated, proprietary databases using non-standardized data formats.
In this environment, many physician offices, particularly those with limited
financial resources, have been reluctant to invest in information technology
solutions. Current solutions may provide connectivity to a single payer or
supplier, or to a limited subset of payers or suppliers, leaving the physician
office with its old manual processes for the majority of its transactions. The
following examples illustrate how poor information management and the lack of
connectivity result in costly, inefficient healthcare services:
 
    ENROLLMENT AND ELIGIBILITY.  The enrollment process typically begins with
employees choosing a health plan and completing paper forms; the employer
manually enters the employee information into its human resources information
system and subsequently sends the data, often via a paper report, to the
relevant health plan. The plan manually enters the information into its
membership system and sends the information, again often in paper form, to other
entities, such as provider groups, pharmacies, pharmacy benefit management
companies and diagnostic laboratories, which in turn must manually enter this
information into their own systems. By the time this process is complete, the
information may be months old and contain data entry errors, and the disparate
healthcare information systems of the various participants may contain
conflicting information about the same member. The participants must then expend
costly, time-consuming extra effort to correct these errors manually. In the
interim, patients may be denied treatment or providers may go unpaid for their
services.
 
    REFERRALS AND AUTHORIZATIONS.  Managed care organizations may require
physicians to obtain prior approval to refer patients to specialists or to
render certain treatments. The approval process often requires physicians to
mail, fax or telephone requests for authorization to the health plan. The plan
manually enters the data into its own system, checks its guidelines regarding
conditions of referral, and replies via mail, fax or telephone with an approval
or denial, a process that can take two days to a week or more. Next, the patient
must schedule an appointment if the request is approved, or seek alternative
care if the request is denied. This lengthy authorization process is costly,
wastes valuable physician time and delays patient care.
 
    CLINICAL INFORMATION EXCHANGE.  To diagnose and treat a patient properly,
physicians need access to clinical information, such as medical history data,
laboratory and x-ray results, and medication lists. However, this information
typically resides in proprietary databases or is stored in paper form.
Therefore, the physician must submit requests for information by phone or fax to
various hospitals, laboratories, outpatient diagnostic centers or provider
offices. Even when the data are stored at the physician's office, it can be
time-consuming to locate in the physician's paper-based medical record system.
As a result, significant delays can occur before the physician obtains the
information required to diagnose the patient's condition accurately. Often,
physicians will require patients to repeat tests for which data are missing,
 
                                       32
<PAGE>
leading to unnecessary expense. More important, the lack of timely access to
accurate clinical information in an urgent care situation may lead to inaccurate
diagnoses resulting in delayed or inappropriate care. The problem is therefore
not only costly, but also potentially harmful.
 
    The limitations and inefficiencies of traditional healthcare information
management ultimately harm the individual consumer. Individual consumers have
little control or influence over how healthcare services are provided, in part
because they lack easy access to information. It can be difficult for consumers
to perform simple tasks, such as changing primary care providers, gaining access
to their own medical records, or monitoring their own care and compliance at
home, because the information they need for these simple tasks requires
time-consuming phone calls or paper correspondence. Consumers, frustrated by
burdensome bureaucracy and lack of empowerment, often fail to take ownership and
control of their own treatment and recovery. The result is higher costs of care
and growing dissatisfaction with the healthcare experience.
 
    HEALTHEON'S OPPORTUNITY
 
    Healtheon believes a significant opportunity exists to leverage the power of
the Internet to provide secure, open, universally accessible network services
that connect participants and automate workflows throughout the healthcare
delivery process. Healtheon believes that such a solution has the potential to
create significant improvements in the way that information is used by the
healthcare system, enabling improved workflows, better decision-making and,
ultimately, higher quality care at a lower cost.
 
THE HEALTHEON VIRTUAL HEALTHCARE NETWORK
 
    Healtheon is pioneering the use of the Internet to simplify workflows,
decrease costs and improve the quality of patient care throughout the healthcare
industry. Healtheon has designed an Internet-based information and transaction
platform that allows it to create Virtual Healthcare Networks that facilitate
and streamline interactions among the myriad participants in the healthcare
industry. The Healtheon VHN solution includes a suite of services delivered
through applications operating on its Internet-based platform. Healtheon VHNs
enable the secure exchange of information among disparate healthcare information
systems and support a broad range of healthcare transactions, including
enrollment, eligibility determination, referrals and authorizations, laboratory
and diagnostic test ordering, clinical data retrieval and claims processing.
Healtheon provides its own applications on the Healtheon Platform and also
enables third-party applications to operate on its platform. The Healtheon
Virtual Healthcare Network solution provides the following key benefits:
 
    ELIMINATION OF UNNECESSARY OR REDUNDANT EFFORTS.  The Healtheon VHN solution
is designed to reduce paper-based transactions, eliminate redundant data entry,
shorten cycle times and decrease the communication inefficiencies created by
isolated proprietary systems. Healtheon believes that by decreasing redundant
tasks, errors, delays, and unnecessary tests and procedures, it can create
efficiencies and reduce costs across the healthcare industry.
 
    EXTENDIBILITY ACROSS THE CONTINUUM OF HEALTHCARE.  Healtheon leverages the
Internet to provide an open, low-cost information and transaction platform
capable of extending across a wide range of healthcare market segments. The
Healtheon VHN solution is designed to interconnect a broad range of practice
management, managed care, human resources and laboratory information systems.
Healtheon expects the benefits of its solution to increase as it adds customers,
enabling each user to exchange more data and complete more transactions with a
greater number and broader range of other healthcare industry participants.
 
    SCALABILITY AND FLEXIBILITY.  The Healtheon VHN solution is designed to
support Healtheon's customers as their businesses grow and evolve. The Healtheon
Platform is designed to scale to accommodate high
 
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<PAGE>
volumes of transactions and large numbers of simultaneous users. In addition,
Healtheon's object-oriented platform provides flexibility so that customers can
add or modify applications and transaction capabilities to react to changes in
the healthcare marketplace.
 
    HIGH DEGREE OF SECURITY.  To enable the use of the Internet for transmission
of highly sensitive and confidential data, Healtheon utilizes advanced
technology designed to ensure a high degree of security. This technology
includes strict authentication requirements, sophisticated data encryption
techniques, system-wide network security monitoring and tightly controlled
physical security systems. These safeguards are designed to provide a secure
environment for the exchange of confidential patient and customer data. The
Healtheon Platform is designed to enable compliance with proposed government
standards under the Health Insurance Portability and Accountability Act of 1996,
which mandate the acceptance by payers of electronic transactions as well as the
use of standard transactions, standard identifiers and security features by the
year 2000.
 
    INCREASED ACCURACY AND TIMELINESS OF INFORMATION.  The Healtheon VHN
solution is designed to increase information flows among all healthcare
participants, which ultimately results in more timely and appropriate
treatments. For example, on-line access to accurate, up-to-date eligibility
information facilitates patients' access to care on a more timely basis, reduces
frustration and costs and increases the likelihood that providers will be
compensated for their services in a timely manner. Similarly, using Healtheon's
VHN solution, consumers will have greater access to their healthcare
information, thereby enabling them to become more active participants in the
provision of their own healthcare.
 
    Healtheon believes that these and other benefits provided by its solution
will result in increased quality of care.
 
STRATEGY
 
    Healtheon's objective is to become the leading provider of Internet-based
transaction and information services to the healthcare industry. Healtheon's
strategy includes the following key elements:
 
    LEVERAGE INTERNET TECHNOLOGY.  Healtheon leverages Internet technology to
create Virtual Healthcare Networks that provide secure transactions and
communications among a broad range of healthcare participants, regardless of
their legacy computing platforms. Unlike traditional proprietary solutions that
focus on point-to-point communications and narrowly defined transactions,
Internet technology allows Healtheon to integrate all categories of healthcare
participants--payers, providers, suppliers and consumers--to eliminate redundant
tasks and reduce costs. Healtheon believes that such connectivity will optimize
and simplify the flow of mission-critical information.
 
    EXPAND FUNCTIONALITY AND TRANSACTION CAPABILITY.  Healtheon seeks to
identify key functions that are critical to particular industry participants and
integrate applications supporting these functions into its VHN. Healtheon plans
to accomplish this by building native, Internet-based applications encompassing
the identified functionality, by acquiring businesses or technologies, and by
enabling industry-leading, third-party applications on its platform. Healtheon
has initially targeted those applications that are most critical to each
business segment of the healthcare industry, offer the highest value to the
participants, and are readily adaptable to a network computing paradigm. For
example, Healtheon developed its Benefits Administration application suite to
automate healthcare plan enrollment and is developing its Healtheon Practice
application suite, which is in use at beta sites, to manage eligibility,
referrals, authorizations and claims transactions between healthcare providers
and payers.
 
    FORM STRATEGIC RELATIONSHIPS WITH LEADING HEALTHCARE
PARTICIPANTS.  Healtheon is aggressively pursuing strategic relationships with
leaders in key healthcare industry segments to increase its portfolio of
applications and services, increase the number of connected users and provide
specialized industry expertise for new applications. In addition, Healtheon
plans to acquire companies with strategic relationships with leading healthcare
industry participants. Healtheon believes this strategy also provides
accelerated market
 
                                       34
<PAGE>
awareness and demand for Healtheon's services through the influence of these
partners both directly, through their use and sales efforts, and indirectly,
through their relationships with other potential customers. To date, Healtheon
has established strategic relationships with leading healthcare organizations,
including: United HealthCare, one of the largest health maintenance
organizations in the United States; SmithKline Labs, one of the largest
independent clinical laboratory companies in the United States; Brown & Toland,
a leading medical group in the San Francisco Bay Area; and Beech Street, one of
the largest preferred provider organizations in the United States.
 
    ESTABLISH A NATIONAL PRESENCE REGION BY REGION.  Healtheon believes that the
value of its applications and services will grow as the number of connected
parties and the breadth of the transactions conducted on Healtheon's platform
increase. However, healthcare remains highly regional, driven by business
relationships and practices that are often unique to specific regions.
Therefore, Healtheon's approach is to target regional markets where it can gain
critical mass and to expand nationally region by region. Healtheon plans to
enter into, and to acquire companies with, strategic relationships with national
and regional healthcare participants that have significant market share in
specific regions. In addition, Healtheon intends to leverage its existing
relationships to penetrate new regions and markets.
 
    PURSUE USAGE-BASED BUSINESS MODEL.  Healtheon offers network-based
transaction and information services on a transaction or subscription fee basis.
This pricing model reduces the initial investment required to obtain the
benefits of high-end information technology systems, enabling physicians, small
organizations and individuals to gain access to these systems for the first
time. By enabling the shift from fixed information technology costs to variable
costs, Healtheon believes that it will be able to achieve a critical mass of
users and broad-based adoption of the Healtheon Virtual Healthcare Network
solution.
 
    PROVIDE A COMPLETE SOLUTION.  In addition to its network-based transaction
and information services, Healtheon offers consulting, application development,
systems integration and network management services to provide complete
customer-specific solutions. By offering this range of services, Healtheon can
provide customers with a complete migration path from the customers' legacy
systems and processes to Healtheon's Internet-based model.
 
HEALTHEON'S SERVICES
 
    Healtheon offers a suite of healthcare transaction and information services
delivered over the Internet or over private intranets and other networks. These
network-based services are provided by software applications operating on or
interfacing with the Healtheon Platform, which is designed to provide
connectivity across the healthcare industry and enable a broad array of secure,
mission-critical healthcare transactions. In addition to its platform and
Internet-based applications, Healtheon provides comprehensive consulting and
implementation services to enable its customers to take full advantage of the
capabilities of Healtheon's platform.
 
    Healtheon provides a broad range of applications and services that support
key healthcare transactions. The components of these application suites can be
combined and modified, or supplemented with new application components, to
provide custom solutions for large, complex, multi-entity business enterprises.
These applications and services are typically sold on a transaction or
subscription fee basis, which varies across customers and market segments. The
following chart summarizes the key transactions supported by Healtheon,
organized by business function.
 
                                       35
<PAGE>
 
<TABLE>
<CAPTION>
         BUSINESS           CUSTOMERS/
         FUNCTION              USERS            TRANSACTIONS SUPPORTED         HEALTHEON SERVICE
<S>                         <C>          <C>                                   <C>
Membership Services          Consumers   - Enrollment                          Benefits
                                Payers   - Plan comparison/selection           Administration
                                         - Provider search, selection, change
                                         - Benefits inquiry
                                         - Messaging
 
Healthcare Administration       Payers   - Eligibility determination           Healtheon Practice
and Financial Management     Providers   - Referrals                           Healtheon
                                         - Authorization                       ProviderWorks*
                                         - Claims submission and status        ProviderLink
                                         - Remittance advice
                                         - Provider directories*
                                         - Provider files-management*
                                         - Reporting
                                         - Claims repricing*
 
Clinical Information         Providers   - Patient identification and          Healtheon Dx*
Services                     Suppliers   encounter history                     SCAN+
                                         - Patient registration                GMPI+
                                         - Lab orders and results
                                         - Text document/transcription
                                           distribution
 
Online Consumer              Consumers   - Access to licensed dictionaries     Healtheon
Information                              and encyclopedias, medical news and   Consumer
                                           other reference sources             Portal
                                         - Customized wellness assessments
                                         - Food label and nutritional library
                                         - Secure communications and
                                           transactions with providers and
                                           health plans*
</TABLE>
 
- ---------
 
*Under development
 
+Not Internet-enabled
 
    The primary applications and services currently available or under
development are described in greater detail below. Certain of these applications
were acquired by Healtheon and are not yet Internet-enabled; Healtheon is
currently redeveloping or replacing these applications to integrate them with
the Healtheon Platform.
 
    MEMBERSHIP SERVICES.  Healtheon provides membership services through its
Benefits Administration service. The Benefits Administration service utilizes
internally developed applications operating on the Healtheon Platform. The
service provides Internet-based connectivity between healthcare payers and
consumers and supports transactions such as selection of health plans and
providers, enrollment for benefits and benefit inquiries. Benefits
Administration users also receive Healtheon's Health Risk Appraisal service,
which provides consumer education in wellness and health risks. Healtheon has
deployed its Benefits Administration service directly and through aggregators to
45 companies, covering approximately 190,000 members.
 
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<PAGE>
    HEALTHCARE ADMINISTRATION AND FINANCIAL MANAGEMENT.  Healtheon supports or
will support healthcare administration and financial management transactions
through its ProviderLink, Healtheon Practice and Healtheon ProviderWorks
services. ProviderLink was licensed by Healtheon's ActaMed subsidiary from
UnitedHealth Group. Healtheon is currently developing a software interface
between the Healtheon Platform and ProviderLink to integrate ProviderLink with
Healtheon's network-based services. ProviderLink is used by providers to support
transactions and workflows with payers. ProviderLink supports transactions such
as eligibility determinations, claims submission and status, and remittance
advice. For example, physicians use ProviderLink to determine eligibility of
patients to receive care and to submit health claims to payers. ProviderLink is
currently deployed in over 4,300 active provider sites in more than 20 major
markets, and processes over 3.2 million transactions per month.
 
    Healtheon has developed Healtheon Practice, a new Internet-based provider
service with support from Brown & Toland, one of Healtheon's strategic partners.
Healtheon Practice, which is in use at beta sites, is designed to provide all of
the functionality of ProviderLink and also support referrals, authorization, and
provider directories reporting. Providers using the Healtheon Practice service
will be able to receive real-time patient eligibility verifications and referral
authorizations over the Healtheon VHN.
 
    Healtheon is developing Healtheon ProviderWorks, a new Internet-based payer
service, with support from Beech Street, one of Healtheon's strategic partners.
Healtheon ProviderWorks is designed to support the creation and management of
networks of providers. The service is designed to manage large, complex provider
directories and files, manage provider relationships and contracts and perform
certain claim processing functions, such as claim repricing. See "-- Strategic
Relationships."
 
    CLINICAL INFORMATION SERVICES.  Healtheon's SCAN product supports ordering
and distribution of clinical tests and test results between SmithKline Labs and
providers using SmithKline Labs' services. ActaMed acquired the SCAN application
from SmithKline Labs. SCAN is deployed on approximately 4,650 installed
workstations serving physicians throughout the United States. SCAN is not
Internet-enabled; however, Healtheon is developing a new Internet-enabled
application called Healtheon Dx, currently in beta testing, that will combine
the functionality of SCAN and ProviderLink. See "-- Strategic Relationships."
 
    Healtheon's Global Master Person Index, or "GMPI," enables the unique
identification of a patient and reconciliation of multiple records for the same
patient contained on diverse information systems. GMPI also supports access to
patient data and registration information as well as clinical records. GMPI is
an object-oriented application developed by ActaMed and is not yet
Internet-enabled. Healtheon intends to adapt and implement GMPI functionality on
the Healtheon Platform.
 
    ONLINE CONSUMER INFORMATION.  Healtheon's recently introduced Consumer
Portal provides individual consumers with an authoritative source for healthcare
information and is intended to extend Healtheon's transaction services directly
to individual consumers. The Consumer Portal provides access to medical
dictionaries and encyclopedias, medical news, a food label and nutritional
library and customized wellness assessments. These sources include: Miller-Keane
Encyclopedia & Dictionary of Medicine, Nursing & Allied Health; Dorland's
Illustrated Medical Dictionary; Citizen 1's CitiLine index of authoritative
medical information; A.D.A.M.'s Hypertext Medical Encyclopedia; and Links to
medical headlines via the New York Times Syndicate. Healtheon's business
partners can integrate the Consumer Portal into their own sites to provide their
consumers with a single point of entry into the healthcare community.
 
    Healtheon expects to expand its Consumer Portal to support secure
communications and transactions between consumers and their providers and health
plans.
 
    OTHER SERVICES.  Healtheon also provides professional services to its
customers to enable them to define, develop and implement network-based
information systems that leverage the capabilities of the Healtheon Platform.
These services are typically sold on a fixed fee or time and materials basis.
These services include consulting on information systems strategy related to the
use of the Internet and secure networks, including design of information systems
functional specifications, mapping and redesign of
 
                                       37
<PAGE>
business processes and identification of enterprise transformation and training
requirements to take advantage of increased connectivity. Healtheon also
provides custom development of applications and enables the deployment of
Healtheon services and integration with legacy information technology systems.
In addition, Healtheon provides transitional network management services of its
customers' networks. Healtheon believes that its success is partially dependent
upon its ability to introduce new applications in several healthcare markets in
a relatively short period of time. Healtheon currently offers a limited number
of applications on its platform.
 
CUSTOMERS AND MARKETS
 
    Healtheon's target customers include providers, payers, suppliers and
consumers. Because Healtheon believes that the value and benefit of Healtheon's
services are directly related to both the number of participants using Healtheon
VHNs and the breadth of functionality supported, it intends initially to focus
on selected regions where it can quickly gain significant market acceptance.
Healtheon is presently targeting a number of regional markets across the United
States.
 
    PROVIDERS.  Healtheon's target provider customers include aggregators of
individual physicians such as large medical groups, independent practice
associations, physician practice management companies and other large, organized
physician entities. In particular, Healtheon seeks to form strategic
relationships with providers with a high degree of involvement in managed care,
especially providers that are involved in activities such as capitation, which
require them to bear some level of insurance risk for each enrolled patient.
Healtheon's services for these providers include benefit eligibility
determinations, referrals and authorizations, claims processing, ordering of
clinical tests and delivery of results and maintenance of patient histories.
Healtheon also targets as potential customers large integrated delivery networks
that combine multiple healthcare facilities, such as hospitals, outpatient
facilities, labs and diagnostic centers, and affiliate with physicians and
physician groups to coordinate care, contract for managed care lives and manage
healthcare resource utilization. Healtheon offers these customers the following
services: patient identification, patient registration, ordering of clinical
tests and delivery of results and distribution of text documents across the
network. Healtheon's current customers in this category include Brown & Toland,
Baylor Health Care System, Hill Physician Group, Promina Health System and the
Greater Dayton Area Hospital Association.
 
    PAYERS.  Healtheon's target payer customers include managed care
organizations, indemnity insurers, third-party administrators and federal and
state governmental agencies. Healtheon targets managed care organization
customers, such as mid-sized to large HMOs and PPOs. Healtheon's services for
these customers include eligibility determination, member customer service
functions, referral and authorization management, coordination of provider files
and directories, and submission and tracking of claims and patient encounter
reports. Healtheon targets indemnity insurer and third-party administrator
customers, such as mid-sized to large commercial entities, Medicare and other
agencies of federal and state government. Healtheon's current customers in this
category consist of UnitedHealth Group, Beech Street, Sun Life of Canada, Blue
Shield of California, CIGNA HealthCare and the Health Care Financing
Administration.
 
    SUPPLIERS.  Healtheon's target supplier customers include large national
laboratory companies, pharmaceutical companies and pharmacy benefit managers.
Healtheon's services for laboratory companies include ordering clinical tests
and reporting test results. Healtheon's customers in this category include
SmithKline Labs and Schering Corporation.
 
    CONSUMERS.  Healtheon's target consumer customers include employers, health
plans and health plan brokers. Healtheon's services in this area include a
consumer web portal, health plan enrollment, benefits administration and
membership coordination. Healtheon's target employer group includes mid-sized
and large employers and, particularly, self-funded employers that have complex
benefits management needs.
 
                                       38
<PAGE>
Healtheon's target health plan broker customers include mid-sized to large
brokers that aggregate small and medium employers and administer healthcare
benefits on their behalf. Healtheon services 45 employers covering approximately
190,000 members.
 
STRATEGIC RELATIONSHIPS
 
    Healtheon has entered into several strategic relationships that it believes
will enhance its application portfolio, provide important specialized industry
expertise, increase its market penetration, and generate revenue. Certain of
these relationships are described below:
 
    UNITEDHEALTH GROUP.  UnitedHealth Group is one of the largest HMOs in the
United States. UnitedHealth Group is Healtheon's second largest stockholder and
will own approximately 13.3% of Healtheon's common stock after the offering. In
March 1996, Healtheon acquired UnitedHealth Group's ProviderLink network which
supports over 4,300 active provider sites in more than 20 major markets
servicing over 3.2 million transactions per month. Healtheon earns transaction
fee revenue by providing certain healthcare information services to UnitedHealth
Group, members of UnitedHealth Group's provider network and ProviderLink
subscribers.
 
    In April 1996, Healtheon and UnitedHealth Group entered into a Services and
License Agreement, the "UnitedHealth Group Agreement," under which Healtheon,
using ProviderLink, provides claims processing, referral, eligibility and
enrollment services, to UnitedHealth Group's managed care providers and
customers. Under the UnitedHealth Group Agreement, Healtheon currently receives
a monthly fee for each user site enrolled with UnitedHealth Group and a fee per
transaction. However, the UnitedHealth Group Agreement does not guarantee any
minimum level of transactions or payments to Healtheon. The UnitedHealth Group
Agreement has a five year term; however, the agreement provides that two years
after the date of the agreement, the parties will agree on new prices that will
be competitive with the marketplace. Healtheon and UnitedHealth Group are
negotiating such new prices, and Healtheon anticipates that the new prices will
reduce the rates paid by UnitedHealth Group. UnitedHealth Group has also agreed
during the term of the UnitedHealth Group Agreement not to promote or contract
for services providing the same functionality as that provided by Healtheon,
although UnitedHealth Group is permitted to continue to utilize services it was
utilizing when it entered into the UnitedHealth Group Agreement.
 
    In addition, through ActaMed, Healtheon has developed PLNet, an
Internet-based version of ProviderLink, which Healtheon intends to integrate
into the Healtheon Platform and offer to other major healthcare payers and
providers. Healtheon is working with UnitedHealth Group to expand the
applications and content available to UnitedHealth Group's provider network, to
increase the size and geographic reach of its provider network, and to
assimilate newly acquired health plans. William McGuire, M.D., the Chairman and
CEO of UnitedHealth Group, is a member of Healtheon's Board of Directors. The
UnitedHealth Group Agreement is effective through March 2001, subject to earlier
termination in the event Healtheon fails to meet certain network performance
standards or otherwise breaches its material obligations under the UnitedHealth
Group Agreement.
 
    SMITHKLINE BEECHAM CLINICAL LABORATORIES, INC.  SmithKline Beecham Clinical
Laboratories, Inc., or "SmithKline Labs," a subsidiary of SmithKline Beecham, is
one of the largest independent clinical laboratories in the United States.
SmithKline is a stockholder of Healtheon and will own approximately 9.1% of
Healtheon's common stock after the offering. In December 1997, Healtheon and
SmithKline Labs entered into a Services Agreement, or the "Services Agreement"
under which Healtheon provides lab orders and results to providers that use
SCAN. SmithKline Labs has also agreed to promote Healtheon as its preferred
vendor for laboratory electronic connectivity services.
 
                                       39
<PAGE>
    Healtheon acquired SCAN-related assets from SmithKline Labs, including
approximately 4,200 installed workstations in physicians' offices, hospitals and
other provider offices. Healtheon is currently developing Healtheon Dx, an
Internet-enabled version of the SCAN system, which Healtheon plans to integrate
into the Healtheon Platform and to offer to physicians using SmithKline Labs'
services or to physicians using other laboratories. Tadataka Yamada, M.D.,
President of SmithKline Beecham Healthcare Services, is a member of Healtheon's
Board of Directors. The Services Agreement is effective through December 2002,
with options for successive two-year renewals, subject to earlier termination in
the event Healtheon fails to meet certain network performance standards or if
Healtheon otherwise breaches its material obligations under the Services
Agreement. The Services Agreement provides that the parties will negotiate new
rates as of January 1, 2001 and each two years thereafter. Pursuant to the
Services Agreement, the renegotiated rates must be competitive with the
marketplace and must be no higher than the lowest fees charged by Healtheon to
similarly situated customers.
 
    In December 1998, Healtheon agreed to purchase, and in January 1999,
Healtheon purchased certain assets used by SmithKline Labs to provide laboratory
results delivery services in exchange for $2.0 million in cash and approximately
1.8 million shares of Healtheon's common stock. Healtheon and SmithKline Labs
entered into a related services agreement under which Healtheon will provide
certain electronic laboratory results delivery services to approximately 20,000
provider sites, in addition to the sites currently served through the SCAN
service. The services agreement has a five year term.
 
    On February 9, 1999, SmithKline Beecham announced that it has agreed to sell
SmithKline Labs to Quest Diagnostics, Incorporated. SmithKline Labs has been one
of our strategic partners since December 1997, and our relationship with them
has been beneficial. Our agreements with SmithKline Labs will remain in effect
as a result of the acquisition.
 
    BROWN & TOLAND PHYSICIAN SERVICES ORGANIZATION.  Brown & Toland Medical
Group, or "BTMG," based in San Francisco, California, is a partnership of
approximately 2,000 physicians representing a merger of physicians from
California Pacific Medical Center, the University of California-San Francisco
and Stanford University. Brown & Toland Physician Services Organization, or
"Brown & Toland", a wholly owned subsidiary of BTMG, is the management company
that administers the managed care risk business on behalf of BTMG and other
physician organizations. In December 1997, Healtheon and Brown & Toland entered
into an agreement under which Healtheon is developing Healtheon Practice, which
Healtheon intends to market to Brown & Toland and other payers and providers.
Healtheon also manages the information technology operations of Brown & Toland.
Through its relationship with Brown & Toland, Healtheon believes it is gaining
valuable industry-segment expertise from a leader in managed care and
accelerating its market presence in the San Francisco Bay Area. Healtheon's
agreement with Brown & Toland is effective through September 2000, although it
may be terminated by either party upon 120 days' notice.
 
    BEECH STREET CORPORATION.  Beech Street is one of the largest PPOs in the
United States. Beech Street's PPO network consists of approximately 4,300
hospitals and 320,000 physician locations serving 15 million individuals in 49
states, and its clients consist of major self-insured employers, insurance
companies and third-party administrators. In December 1997, Healtheon and Beech
Street have entered into an agreement under which Healtheon is developing
Healtheon ProviderWorks, which Healtheon intends to offer to Beech Street and to
other payers and providers. Healtheon also manages the information technology
operations of Beech Street. The relationship with Beech Street provides
Healtheon with important industry-segment expertise and a strategic entry-point
into the PPO market segment. Healtheon's agreement with Beech Street is
effective through December 2002, although it may be terminated by either party
upon 180 days' notice.
 
THE HEALTHEON PLATFORM
 
    The Healtheon Platform is a CORBA-based distributed application framework,
combined with software tools that ensure security, scalability, availability,
reliability and manageability, on which
 
                                       40
<PAGE>
transaction intensive applications can be delivered over the Internet or over
other distributed environments. The Healtheon Platform is deployed on a server
complex at the Healtheon data center in Santa Clara, California, which consists
of SUN Solaris servers in a fault tolerant configuration and redundant or fault
tolerant network components. The Healtheon Platform includes the following
features:
 
    SECURITY.  The Healtheon Platform is designed to ensure the privacy and
integrity of data and communications by using a combination of security
methodologies to provide multiple lines of defense. All Internet communications
between Healtheon and its users employ the Secure Sockets Layer protocol. In
addition, Healtheon utilizes server digital certificates and username/password
schemes to authenticate users. Each user has a unique user ID and has one or
more roles that define the types of functionality and data access available. All
Healtheon's applications record logging information, creating an audit trail,
and protect privacy by encrypting sensitive data. Healtheon also uses a
multi-layered firewall complex to secure the Healtheon network infrastructure.
In addition, network vulnerability scanners are used on a regular basis to
actively monitor security status. Healtheon's physical security systems at its
Santa Clara facility consist of comprehensive physical controls and
multi-layered internal network and information system safeguards. The physical
controls include using fingerprint authentication, dual-level access points, and
multiple alarm systems.
 
    SCALABILITY.  The Healtheon Platform utilizes CORBA-based middleware, which
enables a highly scalable distributed applications infrastructure. The platform
enables an application to run simultaneously on multiple host systems, allowing
for large numbers of simultaneous users while at the same time optimizing
network performance and resource utilization. In addition, the Healtheon
Platform has been designed to transparently deploy new services and hardware
while existing applications remain operational. Finally, the Healtheon Platform
reduces communications bottlenecks resulting from limited numbers of connections
to database servers through intelligent management of database connections and
object caches that reduce the need to query database servers for frequently used
data.
 
    RAPID APPLICATION DEVELOPMENT AND INTEGRATION.  The Healtheon Platform is
designed to enable rapid application development and integration. The platform
supports object-oriented programming, which accelerates the design process
through object reuse. Healtheon maintains a comprehensive set of object
libraries, called core services, that allows developers to build complex
applications rapidly. The platform is also designed for deploying applications
developed by third parties with relative ease. The platform interfaces with
legacy systems by accepting industry standard ANSI X.12 and HL7 electronic data
interchange formats.
 
    HIGH AVAILABILITY.  The Healtheon Platform architecture is designed to
ensure high availability through the replication of applications and other
software services, failure detection and automatic restart of failed services
and applications. Running multiple copies of a service or application removes
any single point of failure within the system and ensures that at least some
copies of a service will be available while others may have failed. In addition,
the servers that host Healtheon applications are duplicated to provide
redundancy. Healtheon uses duplicate fiber optic cable connections to Sprint and
WorldCom to ensure highly-available access to the Internet. Healtheon's platform
uses a mix of fault-tolerant hardware, redundant equipment and back-up power
systems.
 
    MANAGEABILITY.  The Healtheon management framework provides a single image
view of all Healtheon services, thus simplifying administration in a distributed
environment. Healtheon services can be managed from a Web-based management
station. The Healtheon management and administration framework monitors service
performance and generates event notifications of system abnormalities.
 
    DISASTER RECOVERY PLANS.  Although Healtheon believes its operations
facilities are highly resistant to systems failure and sabotage, it has
developed, and is in the process of implementing, a disaster recovery and
 
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<PAGE>
contingency operations plan. In addition, all of Healtheon's services are linked
to advanced storage systems that provide data protection through techniques such
as replication. Healtheon also maintains on-site backup power systems.
 
    AUDITS.  Healtheon's information technology department periodically
performs, and retains accredited third parties to perform, audits of its
operational procedures under both internally-developed audit procedures and
externally-recognized standards.
 
CUSTOMER SUPPORT
 
    Healtheon believes that a high level of customer support is necessary to
achieve wide acceptance of its solution. Healtheon provides a wide range of
customer support services through a staff of customer service personnel,
multiple call centers and an e-mail help desk. Healtheon also offers Web-based
support services that are available 24 hours a day, seven days a week and are
frequently updated to improve existing information and to support new services.
Healtheon also employs technical support personnel who work directly with its
direct sales force, distributors and customers of its applications and services.
Healtheon provides its customers with the ability to purchase maintenance for
its applications and services, which includes technical support and upgrades.
Healtheon also provides training programs for its customers. As of September 30,
1998, Healtheon had 251 employees and independent contractors in customer
support functions, including network services, provider services and customer
support services.
 
SALES AND MARKETING
 
    Healtheon's sales and marketing efforts are organized according to its four
main customer segments: providers, payers, suppliers and consumers. Healtheon's
direct sales force targets significant potential customers in each market
segment by region. In certain instances, Healtheon's direct sales force works
with complementary brokers, value added resellers and systems integrators to
deliver complete solutions for major customers. In addition, senior management
plays an active role in the sales process by cultivating industry contacts.
Healtheon markets its applications and services through direct sales contacts,
strategic relationships, the sales and marketing organizations of its strategic
partners, participation in trade shows, articles in industry publications and by
leveraging its existing client base. Healtheon attends a number of major trade
shows each year and has begun to sponsor executive conferences, which feature
industry experts who address the information systems needs of large healthcare
organizations. Healtheon supports its sales force with technical personnel who
perform demonstrations of Healtheon's applications and assist clients in
determining the proper hardware and software configurations. Healtheon's
executive sales and marketing management is located in its Santa Clara,
California headquarters and in its Atlanta, Georgia, Minneapolis, Minnesota and
San Francisco, California facilities, while its account representatives are
deployed across the United States. As of September 30, 1998, Healtheon employed
67 sales executives, account managers, direct sales representatives and sales
support personnel.
 
DEVELOPMENT AND ENGINEERING
 
    Healtheon believes that its future success will depend in large part on its
ability to continue to maintain and enhance its platform, applications and
services. To this end, Healtheon leverages the modular nature of its platform
architecture to enable it to develop new applications and services rapidly.
Healtheon has developed applications and services both independently and through
acquisitions. Healtheon will continue to work closely with other companies in
its applications development efforts.
 
    Healtheon has several significant projects currently in development. These
include the continued enhancement of the platform architecture, development of
new services such as Healtheon Practice, Healtheon ProviderWorks and Healtheon
Dx, and integration of ActaMed's platform, network and associated services. As
of September 30, 1998, Healtheon employed 201 people in the areas of
applications design, research and development, quality assurance and technical
support.
 
                                       42
<PAGE>
    In 1995, 1996, 1997 and the nine months ended September 30, 1998,
Healtheon's development and engineering expense, which excludes development
expenses included in total cost of revenue, totaled $2.4 million, $8.6 million,
$13.0 million and $13.0 million, representing 112%, 78%, 97% and 39% of its
total revenue. Healtheon believes that timely development of new and enhanced
applications and technology is necessary to remain competitive in the
marketplace. Accordingly, Healtheon intends to continue recruiting and hiring
experienced development personnel and to make other investments in development
and engineering.
 
    The emerging market for healthcare information exchange and transaction
processing is characterized by rapid technological developments, frequent new
application introductions and evolving industry standards. The emerging nature
of this market and its rapid evolution will require that Healtheon continually
improve the performance, features and reliability of its applications and
services, particularly in response to competing offerings, and that it introduce
new applications and services or enhancements to existing applications and
services as quickly as possible and prior to its competitors. The success of new
application and service introductions is dependent on several factors, including
proper definition of new applications or services, timely completion and
introduction of new applications and services, differentiation of new
applications and services from those of Healtheon's competitors and market
acceptance. There can be no assurance that Healtheon will be successful in
developing and marketing new applications and services that respond to
competitive and technological developments and changing customer needs. The
failure of Healtheon to develop and introduce new applications and services
successfully on a timely basis and to achieve market acceptance for its
applications and services could have a material adverse effect on Healtheon's
business, financial condition and results of operations. In addition, the
widespread adoption of new Internet, networking or telecommunication
technologies or standards or other technological changes could render its
applications and services obsolete or require substantial expenditures by
Healtheon to adapt its applications and services. Moreover, there is a risk that
a competitor's product might become the standard for healthcare information
services.
 
INTELLECTUAL PROPERTY
 
    Healtheon relies upon a combination of trade secret, copyright and trademark
laws, license agreements, confidentiality procedures, employee nondisclosure
agreements and technical measures to maintain the secrecy of its intellectual
property. Healtheon believes that patent, trade secret and copyright protection
are less significant to Healtheon's success than its ability to further develop
applications. Healtheon has several trademarks in the United States and
internationally.
 
COMPETITION
 
    The market for healthcare information services is intensely competitive,
rapidly evolving and subject to rapid technological change. Many of Healtheon's
actual and potential competitors have announced or introduced Internet
strategies. Healtheon's competitors can be divided into several groups:
healthcare information software vendors, including HBO & Company, which was
recently acquired by McKesson Corporation, one of the country's largest drug
wholesalers, and Shared Medical Systems Corporation; healthcare electronic data
interchange companies, including ENVOY Corporation, which has agreed to be
acquired by Quintiles Transnational Corp., and National Data Corporation; and
large information technology consulting service providers, including Andersen
Consulting, International Business Machines Corporation and Electronic Data
Systems Corporation. Each of these companies can be expected to compete with
Healtheon within certain segments of the healthcare information technology
market. Furthermore, major software information systems companies and others,
including those specializing in the healthcare industry that are not presently
offering applications that compete with those offered by Healtheon, may enter
Healtheon's markets. In some cases, large customers may have the ability to
compete directly with Healtheon as well. Healtheon also competes with smaller
regional competitors. Many of Healtheon's competitors and potential competitors
have significantly greater financial, technical, product
 
                                       43
<PAGE>
development, marketing and other resources and greater market recognition than
Healtheon. Many of Healtheon's competitors also currently have, or may develop
or acquire, substantial installed customer bases in the healthcare industry. As
a result of these factors, Healtheon's competitors may be able to respond more
quickly to new or emerging technologies and changes in customer requirements or
to devote greater resources to the development, promotion and sale of their
applications or services than Healtheon. There can be no assurance that
Healtheon will be able to compete successfully against current and future
competitors or that competitive pressures faced by Healtheon will not materially
adversely affect its business, financial condition and results of operations.
 
GOVERNMENT REGULATION AND HEALTHCARE REFORM
 
    Laws and regulations may be adopted with respect to the Internet or other
on-line services covering issues such as user privacy, pricing, content,
copyrights, distribution and characteristics and quality of products and
services. The adoption of any additional laws or regulations may impede the
growth of the Internet or other on-line services, which could, in turn, decrease
the demand for Healtheon's applications and services and increase Healtheon's
cost of doing business, or otherwise have an adverse effect on Healtheon's
business, financial condition and results of operations. Moreover, the
applicability to the Internet of existing laws in various jurisdictions
governing issues such as property ownership, sales and other taxes, libel and
personal privacy is uncertain and may take years to resolve. Any such new
legislation or regulation, the application of laws and regulations from
jurisdictions whose laws do not currently apply to Healtheon's business, or the
application of existing laws and regulations to the Internet and other online
services could have a material adverse effect on Healtheon's business, financial
condition and results of operations.
 
    The confidentiality of patient records and the circumstances under which
records may be released for inclusion in Healtheon's databases are subject to
substantial regulation by state governments. These state laws and regulations
govern both the disclosure and the use of confidential patient medical record
information. Although compliance with these laws and regulations is at present
principally the responsibility of the hospital, physician or other healthcare
provider, regulations governing patient confidentiality rights are evolving
rapidly. Additional legislation governing the dissemination of medical record
information has been proposed at both the state and federal level. This
legislation may require holders of this information to implement security
measures that may require substantial expenditures by Healtheon. There can be no
assurance that changes to state or federal laws will not materially restrict the
ability of healthcare providers to submit information from patient records using
Healtheon's applications.
 
    Legislation currently being considered at the federal level could impact the
manner in which Healtheon conducts its business. The Health Insurance
Portability and Accountability Act of 1996 mandates the use of standard
transactions, standard identifiers, security and other provisions by the year
2000. Healtheon is designing its Platform and applications to enable compliance
with the proposed regulations; however, until the proposed regulations become
final, they could change, which could require Healtheon to expend additional
resources to comply with the revised standards. In addition, the success of
Healtheon's compliance efforts may be dependent on the success of healthcare
participants in dealing with the standards.
 
    International regulations with respect to the Internet, privacy and
transborder data flows are considerably more developed than regulations in the
United States. Healtheon intends to develop applications and services to be used
on a worldwide basis and, consequently, will be required to comply with
international regulations regarding the Internet and electronic commerce, as
well as with U.S. regulations. Healtheon has not evaluated the effect that these
regulations would have on its business, and there can be no assurance that such
regulations will not have an adverse effect on Healtheon's ability to compete
internationally.
 
    The United States Food and Drug Administration is responsible for assuring
the safety and effectiveness of medical devices under the Federal Food, Drug and
Cosmetic Act. Computer applications
 
                                       44
<PAGE>
and software are considered medical devices and subject to regulation by the FDA
when they are indicated, labeled or intended to be used in the diagnosis of
disease or other conditions, or in the cure, mitigation, treatment or prevention
of disease, or are intended to affect the structure or function of the body.
Healtheon does not believe that any of its current applications or services are
subject to FDA jurisdiction or regulation; however, Healtheon plans to expand
its application and service offerings into areas that may subject it to FDA
regulation. Healtheon has no experience in complying with FDA regulations.
Healtheon's compliance with FDA regulations could prove to be time consuming,
burdensome and expensive, which could have a material adverse effect on
Healtheon's ability to introduce new applications or services in a timely
manner.
 
EMPLOYEES
 
    As of September 30, 1998, Healtheon had a total of 613 employees and
independent contractors, of whom there were 184 in customer and network
services, 244 in development and engineering, 14 in consulting services, 67 in
provider services, 67 in sales and marketing and 37 in corporate finance and
administration. None of Healtheon's employees is represented by a labor union,
and Healtheon has never experienced a work stoppage. Healtheon believes its
relationship with its employees to be good. Healtheon's ability to achieve its
financial and operational objectives depends in large part upon its continuing
ability to attract, integrate, retain and motivate highly qualified sales,
technical and managerial personnel, and upon the continued service of its senior
management and key sales and technical personnel, most of whom are not bound by
an employment agreement. Competition for such qualified personnel in Healtheon's
industry and geographical location in the San Francisco Bay Area is intense,
particularly in software development and technical personnel.
 
FACILITIES
 
    Healtheon's principal executive and corporate offices and development and
network operations are located in Santa Clara, California, in approximately
50,000 square feet of leased office space under a lease that expires in March
2008. Healtheon also maintains sales, development and network operations in
Atlanta, Georgia, in approximately 41,000 square feet of leased office space
under a lease that expires in July 2001; sales, engineering and support
operations in Minneapolis, Minnesota, in approximately 16,500 square feet of
leased office space under a lease that expires in December 1999; and sales,
engineering and support operations in San Francisco, California, in
approximately 6,000 square feet and 5,000 square feet of leased office space
under two leases that expire in November 2000 and September 2001. Healtheon
believes that its facilities are adequate for its current operations and that
additional leased space can be obtained if needed.
 
                                       45
<PAGE>
                                   MANAGEMENT
 
EXECUTIVE OFFICERS AND DIRECTORS
 
    The following table sets forth certain information regarding Healtheon's
current executive officers and directors:
 
<TABLE>
<CAPTION>
NAME                                              AGE                                 POSITION
- --------------------------------------------  -----------  --------------------------------------------------------------
<S>                                           <C>          <C>
James H. Clark(1)(2)........................          53   Chairman of the Board of Directors
W. Michael Long(3)..........................          46   Chief Executive Officer and Director
Michael K. Hoover...........................          44   President and Director
Mark Bailey.................................          40   Vice President, Business Development
Kallen Chan.................................          44   Corporate Controller
Jack Dennison...............................          42   Vice President and General Counsel
Dennis Drislane.............................          49   Vice President, Customer and Network Services
Edward Fotsch, M.D..........................          42   Vice President, Physician and Integrated Delivery Network
                                                             Group
Nancy Ham...................................          37   Vice President, Laboratories and Pharmaceuticals
J. Philip Hardin............................          35   Vice President, Managed Care Group
John R. Hughes, Jr..........................          46   Vice President, Provider Services
Krishna Kolluri.............................          36   Vice President, Applications
Matthew Moore...............................          34   Vice President, Consumer Internet Services
Pavan Nigam.................................          39   Vice President, Engineering
Charles Saunders, M.D.......................          44   Vice President, Marketing and Consulting Services and Medical
                                                             Director
John L. Westermann III......................          53   Vice President, Chief Financial Officer, Secretary and
                                                             Treasurer
L. John Doerr(1)(2).........................          46   Director
Thomas A. Jermoluk..........................          42   Director
C. Richard Kramlich(1)(2)...................          63   Director
William W. McGuire, M.D.(1)(2)..............          50   Director
P. E. Sadler(1).............................          64   Director
Laura D'Andrea Tyson........................          50   Director
Tadataka Yamada, M.D.(1)....................          53   Director
</TABLE>
 
- ---------
 
(1) Member of the Audit Committee.
 
(2) Member of the Compensation Committee.
 
(3) Member of the Stock Option Committee.
 
    JAMES H. CLARK has served as Chairman of the Board of Healtheon since he
co-founded it in December 1995. Dr. Clark co-founded Netscape Communications
Corporation in April 1994 and has served as the Chairman of the Board of
Directors of Netscape since its inception. He served as President and Chief
Executive Officer of Netscape from its founding until December 1994. From 1981
until 1994, Dr. Clark served as Chairman of the board of directors of Silicon
Graphics, Inc., a company that he founded in 1981. Prior to founding Silicon
Graphics, Dr. Clark was an Associate Professor at Stanford University. He holds
a B.S. and an M.S. from the University of New Orleans and a Ph.D. from the
University of Utah.
 
    W. MICHAEL LONG has served as Chief Executive Officer and a director of
Healtheon since joining Healtheon in July 1997. Prior to joining Healtheon, Mr.
Long was President and Chief Executive Officer of
 
                                       46
<PAGE>
CSC Continuum, Inc., a unit of Computer Sciences Corporation, from August 1996
to July 1997. For more than five years prior to its acquisition by CSC, he was
President and Chief Executive Officer of The Continuum Company, Inc., a provider
of IT and consulting services to the financial industry. He holds a B.A. from
the University of North Carolina.
 
    MICHAEL K. HOOVER has served as President and a director of Healtheon since
Healtheon acquired ActaMed Corporation in May 1998. Mr. Hoover co-founded
ActaMed in May 1992, and served as its President from its inception to May 1998,
and as its President and Chief Executive Officer from December 1995 to May 1998.
From 1989 to 1992, Mr. Hoover served as the Executive Director of Financial
Services of the MicroBilt division of First Financial Management Corporation.
Prior to that, he founded FormMaker Software Corporation, a producer of
electronic forms automation systems, and served as its Chief Executive Officer
from 1982 to 1988 and as its Executive Vice President during 1988.
 
    MARK BAILEY has served as Vice President, Business Development of Healtheon
since joining Healtheon in July 1998. Prior to joining Healtheon, Mr. Bailey
served as general partner at Venrock Associates, the venture capital
organization for the Rockefeller family, from October 1997 to April 1998. Prior
to that he was Senior Vice President Business Development at Symantec
Corporation, a provider of productivity and utilities software, where he
directed mergers and acquisitions efforts from December 1989 to October 1997.
Before joining Symantec, he was an associate with Kleiner Perkins Caufield &
Byers, a venture capital firm, from June 1985 to December 1989. Mr. Bailey holds
an MBA from Harvard University and a BSE from Princeton University.
 
    KALLEN CHAN has served as Corporate Controller of Healtheon since April
1996. Prior to joining Healtheon, Mr. Chan was the Director of Audit and Group
Controller for Worldwide Manufacturing at Cirrus Logic, Inc. since March 1995.
From January 1993 to February 1995, Mr. Chan was Vice President of Finance and
Chief Financial Officer of Comtech Labs Inc., a video imaging technology
company. From 1986 to 1992, Mr. Chan served as Chief Financial Officer for
various early stage companies, including Caeco Inc., Harmonic Lightwaves, Inc.
and Oasic Technology, Inc. Prior to 1986, Mr. Chan spent nine years at Philips
Semiconductor as a Division Controller. He holds a B.S. in commerce and an
M.B.A. from the University of Santa Clara.
 
    JACK DENNISON has served as Vice President and General Counsel of Healtheon
since joining Healtheon in July 1998. Mr. Dennison served as Deputy General
Counsel of Computer Sciences Corporation from August 1996 to July 1998. Prior to
that time, Mr. Dennison served as Vice President and General Counsel of The
Continuum Company, Inc. Prior to joining Continuum in 1989, he was a partner
with Ford, Dennison & Byrne in Austin, Texas. Mr. Dennison holds a B.A. and a
J.D. from the University of Texas.
 
    DENNIS DRISLANE has served as Vice President, Customer and Network Services
of Healtheon since joining Healtheon in July 1997. Mr. Drislane served as Vice
President, Communications Industry Group, at Electronic Data Systems
Corporation, "EDS," from June 1995 to July 1997. From October 1992 to June 1995,
he was President of EDS' Healthcare Division. Prior to October 1992, he held
various management positions for EDS. Mr. Drislane holds both a B.S. and an M.S.
in business administration from California State University in Sacramento.
 
    EDWARD FOTSCH, M.D. has served as the Vice President, Physician and
Integrated Delivery Network group of Healtheon since Healtheon acquired Metis,
LLC in August 1998. Dr. Fotsch served as President and Chief Executive Officer
of Metis, LLC from March 1997 to August 1998. Prior to working at Metis, LLC,
Dr. Fotsch served as Vice President of Healthcare for NetSource Communications
Inc., an Internet development and consulting organization, from November 1994 to
March 1997. Prior to working at NetSource, Dr. Fotsch was President of Med-Tech
Consulting, a healthcare consulting firm from October 1992 through November
1994. Dr. Fotsch practiced medicine as Chief of the Department of Emergency
Medicine at Doctors Hospital in Northern California for ten years prior to 1994.
He holds a Doctorate in Medicine from the Medical College of Wisconsin and a
B.S. from Marquette University.
 
                                       47
<PAGE>
    NANCY HAM has served as Vice President, Laboratories and Pharmaceuticals
Group of Healtheon since Healtheon acquired ActaMed in May 1998. Ms. Ham served
as a Senior Vice President of ActaMed from June 1996 to May 1998. She served as
Chief Financial Officer and Secretary of ActaMed from 1993 to May 1996. From
1992 to 1993, she was a Corporate Finance Director for the Capital Finance Group
of Equifax, Inc. Prior to that, she was an Assistant Vice President at G.E.
Capital Corporation. Ms. Ham holds a B.A. in economics from Duke University and
a masters in international business studies from the University of South
Carolina.
 
    J. PHILIP HARDIN has served as Vice President, Managed Care Group of
Healtheon since Healtheon acquired ActaMed in May 1998. Mr. Hardin served as
Vice President of Managed Care Operations of ActaMed from August 1997 until May
1998. He also served as Director of payer Sponsorship for ActaMed from January
1997 to August 1997, and Project Executive from July 1995 to December 1996. From
August 1993 to June 1995, Mr. Hardin attended Stanford University and received
an MBA degree in June 1995. Prior to that, he served as Vice President, Finance,
Director of Finance and Controller of Melita International Corporation and held
various accounting positions at Arthur Andersen & Company. Mr. Hardin also holds
a B.B.A. in accounting from the University of Georgia.
 
    JOHN R. HUGHES, JR. has served as Vice President, Provider Services of
Healtheon since Healtheon acquired ActaMed in May 1998. Mr. Hughes served as
Chief Operating Officer of ActaMed from March 1996 to May 1998. Prior to working
at ActaMed, Mr. Hughes served as General Manager of the EDI Services Group of
UnitedHealth Group from August 1992 to March 1996. Mr. Hughes served as Vice
President of North American Sales for Revelation Technologies, a computer
software company, from 1990 to 1992. From 1980 to 1990, Mr. Hughes was Vice
President, Sales Manager and Product Marketing Manager at Harris Corporation.
Mr. Hughes holds a B.S. in business administration from the University of
Kansas.
 
    KRISHNA KOLLURI has served as Vice President, Applications of Healtheon
since July 1998, and prior to that, as Senior Director of Development
Engineering of Healtheon since February 1996. Prior to joining Healtheon, Mr.
Kolluri spent six years at Silicon Graphics, Inc. From August 1993 to February
1996, Mr. Kolluri served as Senior Engineering Manager of Applications and
Development Environments in the Interactive Media Group of Silicon Graphics,
Inc. From May 1992 to August 1993, he served as Senior Engineering Manager of
Programming Environments in Silicon Graphics' CASE group where he was involved
in the development and deployment of interactive TV projects in Orlando, Florida
and Urayasu, Japan. From March 1990 to May 1992, he was a Member of Silicon
Graphic's technical staff. Mr. Kolluri holds a B.S.M.E. from the Indian
Institute of Technology, Madras, India, an M.S. in Operations Research from
S.U.N.Y., Buffalo, and an M.S.C.S. from the University of California, Santa
Cruz.
 
    MATTHEW MOORE has served as Vice President, Consumer Internet Services since
joining Healtheon in September 1998. Prior to joining Healtheon, Mr. Moore spent
four years at Netscape Communications, where he co-founded the firm's European
operations and served as Director of Strategic Sales from August 1994 until
December 1997. Commencing January 1998, he moved to Netscape's U.S. operations
to head up vertical markets internationally. From 1989 to 1994, he was a partner
at Keystone Strategies, a technology consultancy firm based in Geneva,
Switzerland. Mr. Moore holds a B.A. from University of California, Los Angeles,
and an M.B.A from Hautes Etudes Commerciales, University of Geneva, Switzerland.
 
    PAVAN NIGAM co-founded Healtheon and has served as its Vice President,
Engineering since February 1996. Prior to joining Healtheon, Mr. Nigam worked at
Silicon Graphics from August 1989 to January 1996, where he was the division
manager for Silicon Graphic's Interactive Media Group and was responsible for
deploying Time Warner, Inc.'s Interactive TV project in Orlando, Florida. From
1989 to 1993, he was director of Silicon Graphics' Casevision products. Prior to
1989, Mr. Nigam was employed by Atherton Technologies and Intel Corporation. Mr.
Nigam holds a B.S.E.E. from the Indian Institute of Technology and an M.S.C.S.
from the University of Wisconsin-Madison.
 
                                       48
<PAGE>
    CHARLES SAUNDERS, M.D. has served as Vice President, Marketing and
Consulting Services and Medical Director since joining Healtheon in September
1997. Prior to joining Healtheon, Dr. Saunders was a principal in the consulting
firm of A.T. Kearney, Inc./Electronic Data Systems Corporation from September
1994 to August 1997. Prior to that time, Dr. Saunders was Executive Director of
managed care programs at San Francisco General Hospital, and served as Medical
Director of the San Francisco
Department of Public Health, Paramedic Division, from 1988 to 1994. He has
conducted healthcare systems research for and has served on the faculties of the
University of California at San Francisco, Vanderbilt University and the
University of Colorado. Dr. Saunders holds a B.S. in biology from the University
of Southern California and an M.D. from Johns Hopkins University.
 
    JOHN L. WESTERMANN III has served as Vice President, Chief Financial
Officer, Secretary and Treasurer of Healtheon since joining Healtheon in July
1998. From August 1996 to July 1998, Mr. Westermann was Chief Financial Officer
and Vice President of CSC Continuum, Inc., a unit of Computer Sciences
Corporation. For more than five years prior to its acquisition by CSC, Mr.
Westermann was Chief Financial Officer, Vice President, Secretary and Treasurer
of The Continuum Company, Inc., a provider of IT and consulting services to the
financial industry. Mr. Westermann holds a B.A. from Northwestern University and
an M.B.A. from the University of Chicago Graduate School of Business.
 
    L. JOHN DOERR has served as a director of Healtheon since July 1997. He has
been a general partner at Kleiner Perkins Caufield & Byers, or "KPCB," a venture
capital firm, since 1980. Prior to joining KPCB, Mr. Doerr worked at Intel
Corporation for five years. He is a director of At Home Corporation, Amazon.com,
Inc., Netscape Communications Corporation, Intuit Inc., Platinum Software
Corporation and Sun Microsystems, Inc. He holds a B.S.E.E. and an M.E.E. from
Rice University and an M.B.A. from Harvard Business School.
 
    THOMAS A. JERMOLUK has served as a director of Healtheon since February
1999. Mr. Jermoluk has been Chairman of the Board, President and Chief Executive
Officer of @Home Corporation since he joined @Home in July 1996. From 1994 to
July 1996, he was President and, from 1992 to July 1996, he was Chief Operating
Officer of Silicon Graphics, Inc., a visual computing company. From 1991 to
1994, Mr. Jermoluk was Executive Vice President of Silicon Graphics, and, from
1988 to 1991, he was Vice President and General Manager of Silicon Graphics'
Advanced System Division. From October 1993 to August 1996, he was a member of
the board of directors of Silicon Graphics. Prior to joining Silicon Graphics in
1986, Mr. Jermoluk managed a variety of hardware and software development
projects at Hewlett-Packard Company and Bell Laboratories. He currently serves
on the board of directors of @Home Corporation and Forte Software, Inc. Mr.
Jermoluk holds B.S. and M.S. degrees in Computer Science from Virginia Tech.
 
    C. RICHARD KRAMLICH has served as a director of Healtheon since July 1996.
Mr. Kramlich is the co-founder and has been a General Partner of New Enterprise
Associates, a venture capital firm, since 1978. He is a director of Ascend
Communications, Inc., Com 21, Inc., Lumisys, Inc., Silicon Graphics, Inc., and
Chalone Wine Group, Inc. Mr. Kramlich holds a B.A. from Northwestern University
and an M.B.A. from Harvard Business School.
 
    WILLIAM W. MCGUIRE, M.D. has served as a director of Healtheon since
Healtheon acquired ActaMed in May 1998. He has been the President of
UnitedHealth Group since 1989 and the Chief Executive Officer and Chairman of
the Board of Directors of UnitedHealth Group since 1991. Prior to this, Dr.
McGuire was Executive Vice President and Chief Operating Officer of UnitedHealth
Group. Prior to this time, he served as President and Chief Operating Officer of
Peak Health Plan. Before becoming President and Chief Operating Officer, he held
a number of other positions within that organization. Dr. McGuire practiced
medicine in Colorado, specializing in cardiopulmonary medicine. He holds a B.A.
from the University of Texas and an M.D. from the University of Texas Medical
Branch.
 
    P. E. SADLER has served as a director of the Company since Healtheon
acquired ActaMed in May 1998. He was Chairman of the Board of ActaMed from the
time that he helped co-found it in 1992 until it was acquired by Healtheon, and
served as its Chief Executive Officer from 1992 until May 1996. Prior to
 
                                       49
<PAGE>
founding ActaMed, Mr. Sadler founded MicroBilt Corporation, a computer
processing company, and served as its Chairman, Chief Executive Officer and
President from 1981 until MicroBilt was acquired by First Financial Management
Corporation, or "FFMC," in 1989. Following the acquisition of MicroBilt, he
served as President of the MicroBilt division of FFMC until 1991. Mr. Sadler
also founded Agency Data Systems in 1972 and served as its President until the
company was acquired in 1975. Mr. Sadler also served on the board of
Knowledgeware, Inc. from 1990 to 1995 and currently serves on the Board of
Directors of Central Parking, Inc., an operator of parking lots. Mr. Sadler
holds a B.A. in business and economics from Vanderbilt University.
 
    LAURA D'ANDREA TYSON has served as a director of Healtheon since February
1999. Dr. Tyson has been the Dean of the Haas School of Business Administration
at the University of California at Berkeley since 1996. Dr. Tyson served as
National Economic Advisor to the President of the United States from March 1995
to December 1996 and as Chair of the White House Council of Economic Advisers
from 1993 to 1995. She also served as a member of the President's National
Security Council and Domestic Policy Council. Dr. Tyson was Director of the
Institute of International Studies from 1990 to 1992, and Research Director of
The Berkeley Roundtable on the International Economy from 1986 to 1992, at the
University of California, Berkeley, where she was also a professor of economics
and business administration.
 
    TADATAKA YAMADA, M.D. has served as a director of Healtheon since Healtheon
acquired ActaMed in May 1998. Dr. Yamada has been President and Executive
Director of SmithKline Beecham HealthCare Services since February 1996 and has
been a non-executive director of SmithKline Beecham's Board of Directors since
February 1994. From June 1990 to February 1996, Dr. Yamada was Chairman of the
Internal Medicine department and Physician-in-Chief of the University of
Michigan Medical Center. Prior to that time, Dr. Yamada was a Professor and
Chief of the Gastroenterology Division at the University of Michigan Medical
School's Internal Medicine department. Prior to his work at the University of
Michigan, Dr. Yamada was an associate professor of medicine at the UCLA School
of Medicine. Dr. Yamada is also a director of Genevco, Inc. Dr. Yamada holds a
B.A. in history from Stanford University and an M.D. from the New York
University School of Medicine.
 
    Healtheon's Bylaws authorize between six and eleven directors. The size of
the Board of Directors is currently set at ten. The Certificate of Incorporation
and the Bylaws of Healtheon also provide for a staggered Board. Under a
staggered Board, each director is designated to one of three categories. Each
year the directors' positions in one of the three categories are subject to
election so that it would take up to three years to replace the entire Board,
absent resignation or premature expiration of a director's term. Executive
officers of Healtheon are appointed by the Board and serve at the discretion of
the Board. There are no family relationships among any of the directors or
executive officers of Healtheon.
 
BOARD COMMITTEES
 
    The Board currently has three committees: an Audit Committee, a Stock Option
Committee and a Compensation Committee.
 
    The Audit Committee is currently comprised of Dr. Clark, Mr. Doerr, Mr.
Kramlich, Dr. McGuire, Mr. Sadler and Dr. Yamada. The Audit Committee reviews
and recommends to the Board the internal accounting and financial controls for
Healtheon and the accounting principles and auditing practices and procedures to
be used for the financial statements of Healtheon. The Audit Committee makes
recommendations to the Board concerning the engagement of independent public
accountants and the scope of the audit to be undertaken by such accountants.
 
    The Stock Option Committee is currently comprised of Mr. Long and is charged
with overseeing the stock option plans as they relate to employees other than
officers and directors of Healtheon.
 
    The Compensation Committee is currently comprised of Dr. Clark, Mr. Doerr,
Mr. Kramlich, and Dr. McGuire. The Compensation Committee reviews and recommends
to the Board policies, practices and
 
                                       50
<PAGE>
procedures relating to the compensation of the officers and other managerial
employees and the establishment and administration of employee benefit plans.
The Committee exercises all authority under Healtheon's employee equity
incentive plans and advises and consults with the officers of Healtheon
regarding managerial personnel policies.
 
DIRECTOR COMPENSATION
 
    Directors do not receive any cash fees for their service on the Board or any
Board committee, but they are entitled to reimbursement for all reasonable
out-of-pocket expenses incurred in connection with their attendance at Board and
Board committee meetings. Upon completion of this offering, all Board members
will be eligible to receive stock options under the 1996 Plan, and outside
directors will receive stock options pursuant to automatic grants of stock
options under the 1996 Plan. In July 1998, Healtheon granted to each of Drs.
McGuire and Yamada an option to purchase 30,000 shares of its common stock under
the 1996 Plan with an exercise price equal to $7.00 per share. In October 1998,
Drs. McGuire and Yamada each agreed to exchange his option for a new option with
an exercise price of $3.55 per share, reflecting the fair market value of
Healtheon's common stock on that date as determined by the Board of Directors
after taking into account Healtheon's financial results and prospects. In
connection with this repricing, the vesting of the options for Drs. McGuire and
Yamada was restarted. Therefore, 25% of their shares will vest in October 1999,
and the remainder will vest ratably over the subsequent three years. In February
1999, Healtheon granted to each of Mr. Jermoluk and Dr. Tyson an option to
purchase 30,000 shares of its common stock under the 1996 Plan with an exercise
price equal to $5.85 per share. The Board also determined that under the 1996
Plan each outside director will automatically receive an option to purchase
20,000 shares of common stock annually.
 
COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION
 
    Dr. Yamada, a member of the Compensation Committee, is a director and
executive officer of SmithKline Beecham, which, through its subsidiary
SmithKline Labs, beneficially owns 9.8% of Healtheon's common stock prior to
this offering, and has entered into the Services Agreement and certain other
agreements with Healtheon. Dr. McGuire, a member of the Compensation Committee,
is the Chairman and Chief Executive Officer of UnitedHealth Group, which, with
its affiliates, beneficially owns approximately 14.4% of Healtheon's common
stock prior to this offering, and has entered into the UnitedHealth Group
Agreement and certain other agreements with Healtheon. See "Certain
Transactions." No interlocking relationship exists between the Board or
Compensation Committee and the board of directors or compensation committee of
any other company, nor has any interlocking relationship existed in the past.
 
LIMITATION ON LIABILITY AND INDEMNIFICATION MATTERS
 
    Healtheon's Certificate of Incorporation and Bylaws limit or eliminate the
personal liability of its directors for monetary damages for breach of the
directors' fiduciary duty of care. The duty of care generally requires that,
when acting on behalf of the corporation, directors exercise an informed
business judgment based on all material information reasonably available to
them. Consequently, a director or officer will not be personally liable to
Healtheon or its stockholders for monetary damages for breach of fiduciary duty
as a director, except for
 
    - any breach of the director's duty of loyalty to Healtheon or its
      stockholders;
 
    - acts or omissions not in good faith or that involve intentional misconduct
      or a knowing violation of law;
 
    - unlawful payments of dividends or unlawful stock repurchases, redemptions
      or other distributions; and
 
                                       51
<PAGE>
    - any transaction from which the director derived an improper personal
      benefit.
 
    These provisions are permitted under Delaware law.
 
    Healtheon's Certificate of Incorporation also provides that Healtheon will
indemnify, to the fullest extent permitted by law, any person made or threatened
to be made a party to any action or proceeding by reason of the fact that he or
she is or was a director or officer of Healtheon or serves or served at any
other enterprise as a director, officer or employee at Healtheon's request.
 
    Healtheon's Bylaws provide that Healtheon will, to the maximum extent and in
the manner permitted by Delaware law, indemnify each of the following persons
against expenses, including attorneys' fees, judgments, fines, settlements, and
other amounts incurred in connection with any proceeding arising by reason of
the fact that he or she is or was an agent of Healtheon:
 
    - a current or past director or officer of Healtheon or any subsidiary of
      Healtheon;
 
    - a current or past director or officer of another enterprise who served at
      the request of Healtheon; or
 
    - a current or past director or officer of a corporation that was a
      predecessor corporation of Healtheon or any of its subsidiaries or of
      another enterprise at the request of a predecessor corporation or
      subsidiary.
 
    Healtheon intends to enter into Indemnification Agreements with each of its
directors and executive officers to give them additional contractual assurances
regarding the scope of the indemnification described above and to provide
additional procedural protections. These agreements, among other things,
indemnify Healtheon's directors and executive officers for certain expenses,
including attorneys' fees, judgments, fines, penalties and settlement amounts
incurred by them in any action or proceeding arising out of their services to
Healtheon, its subsidiaries or any other enterprise to which they provide
services at Healtheon's request. In addition, Healtheon intends to obtain
directors' and officers' insurance providing indemnification for Healtheon's
directors, officers and certain employees for certain liabilities. Healtheon
believes that these indemnification provisions and agreements are necessary to
attract and retain qualified directors and officers.
 
    The limited liability and indemnification provisions in Healtheon's
Certificate of Incorporation and Bylaws may discourage stockholders from
bringing a lawsuit against directors for breach of their fiduciary duty and may
reduce the likelihood of derivative litigation against directors and officers,
even though a derivative action, if successful, might otherwise benefit
Healtheon and it stockholders. Furthermore, a stockholder's investment in
Healtheon may be adversely affected to the extent Healtheon pays the costs of
settlement and damage awards against directors and officers of Healtheon under
these indemnification provisions.
 
    At present, there is no pending or threatened litigation or proceeding
involving any director, officer or employee of Healtheon where indemnification
is expected to be required or permitted, and Healtheon is not aware of any
threatened litigation or proceeding that might result in a claim for
indemnification.
 
                                       52
<PAGE>
EXECUTIVE COMPENSATION
 
    The following table sets forth information concerning the compensation
earned for services rendered to Healtheon in 1998 by (1) Healtheon's Chief
Executive Officer and (2) Healtheon's four other most highly compensated
executive officers who earned more than $100,000 in 1998 and were serving as
executive officers at the end of 1998 (collectively, the "Named Executive
Officers"). Under the rules of the Securities and Exchange Commission, this
table does not include certain perquisites and other benefits received by the
Named Executive Officers which do not exceed the lesser of $50,000 or 10% of any
such officer's salary and bonus disclosed in this table.
 
                           SUMMARY COMPENSATION TABLE
 
<TABLE>
<CAPTION>
                                                                                                   LONG-TERM
                                                                                                 COMPENSATION
                                                                                                    AWARDS
                                                                                              -------------------
                                                                       ANNUAL COMPENSATION        SECURITIES
                                                                     -----------------------      UNDERLYING
NAME AND PRINCIPAL POSITION                                          SALARY($)   BONUS($)(1)      OPTIONS(#)
- -------------------------------------------------------------------  ----------  -----------  -------------------
<S>                                                                  <C>         <C>          <C>
W. Michael Long
  Chief Executive Officer..........................................  $  458,337   $      --                --
Michael K. Hoover(2)
  President........................................................     154,487      60,000            80,000
Dennis Drislane
  Vice President, Customer and Network Services....................     163,500      73,500                --
Pavan Nigam
  Vice President, Engineering......................................     225,000          --           325,000
Charles Saunders
  Vice President, Marketing and Consulting Services and Medical
  Director.........................................................     151,250      45,000           200,000(3)
</TABLE>
 
- ---------
 
(1) Some employee year-end bonus amounts for 1998 have not been determined yet
    by the Board of Directors.
 
(2) Mr. Hoover joined Healtheon in May 1998.
 
(3) Includes 100,000 shares underlying an option granted in 1998 that was
    cancelled under a stock option repricing exchange program in October 1998.
 
                                       53
<PAGE>
               OPTION GRANTS DURING YEAR ENDED DECEMBER 31, 1998
 
    The following table sets forth certain information for the year ended
December 31, 1998 with respect to grants of stock options to each of the Named
Executive Officers. All options granted by Healtheon in 1998 were granted under
its 1996 Stock Plan. These options have a term of 10 years. See "--Employee
Benefit Plans" for a description of the material terms of these options.
Healtheon granted options to purchase common stock and issued shares of common
stock pursuant to restricted stock purchase agreements equal to a total of
8,652,907 shares during 1998. This amount includes 2,057,950 shares underlying
options granted and 568,732 shares issued pursuant to restricted stock purchase
agreements in connection with a repricing program in October 1998 and on
December 14, 1998. Options were granted at an exercise price equal to the fair
market value of Healtheon's common stock, as determined in good faith by the
Board of Directors. The Board of Directors determined the fair market value
based on Healtheon's financial results and prospects, the share price derived
for arms-length transactions, and evaluations conducted by valuation experts.
Potential realizable values are net of exercise price before taxes, and are
based on the assumption that the common stock of Healtheon appreciates at the
annual rate shown, compounded annually, from the date of grant until the
expiration of the ten-year term. These numbers are calculated based on
Securities and Exchange Commission requirements and do not reflect Healtheon's
projection or estimate of future stock price growth.
 
<TABLE>
<CAPTION>
                                                                                                            POTENTIAL REALIZABLE
                                                                      INDIVIDUAL GRANTS                       VALUE AT ASSUMED
                                                       ------------------------------------------------         ANNUAL RATES
                                                       NUMBER OF    % OF TOTAL                                 OF STOCK PRICE
                                                       SECURITIES    OPTIONS                                    APPRECIATION
                                                       UNDERLYING   GRANTED TO   EXERCISE                      FOR OPTION TERM
                                                        OPTIONS     EMPLOYEES    PRICE PER   EXPIRATION   -------------------------
NAME                                                    GRANTED      IN 1998       SHARE        DATE          5%           10%
- -----------------------------------------------------  ----------   ----------   ---------   ----------   ----------   ------------
<S>                                                    <C>          <C>          <C>         <C>          <C>          <C>
W. Michael Long......................................        --         --%        $  --            --    $     --     $       --
Michael K. Hoover....................................    80,000        0.9          3.55        6/2/08     178,606        452,623
Dennis Drislane......................................        --         --            --            --          --             --
Pavan Nigam..........................................   325,000        3.8          4.50        7/8/08     919,758      2,330,848
Charles Saunders.....................................   100,000(1)     1.2          4.50            --(1)  283,003(1)     717,184(1)
                                                        100,000        1.2          3.55      10/21/08     223,258        565,779
</TABLE>
 
- ---------
 
(1) Represents an option to purchase 100,000 shares of common stock granted to
    Dr. Saunders in 1998 that was cancelled pursuant to a stock option repricing
    exchange program in October 1998.
 
                                       54
<PAGE>
AGGREGATED OPTION EXERCISES IN LAST FISCAL YEAR AND 1998 YEAR-END OPTION VALUES
 
    The following table sets forth information with respect to the Named
Executive Officers concerning exercisable and unexercisable options held as of
December 31, 1998. The value of in-the-money options is based on the offering
price of $8.00 per share and net of the option exercise price.
 
<TABLE>
<CAPTION>
                                                                 NUMBER OF SECURITIES
                                                                UNDERLYING UNEXERCISED       VALUE OF UNEXERCISED
                                                                      OPTIONS AT           IN-THE- MONEY OPTIONS AT
                                                                 DECEMBER 31, 1998(1)          DECEMBER 31, 1998
                        SHARES ACQUIRED ON   VALUE REALIZED   --------------------------  ---------------------------
NAME                       EXERCISE (#)           ($)         EXERCISABLE  UNEXERCISABLE  EXERCISABLE   UNEXERCISABLE
- ----------------------  ------------------  ----------------  -----------  -------------  ------------  -------------
<S>                     <C>                 <C>               <C>          <C>            <C>           <C>
W. Michael Long.......         400,000        $  1,320,000(1)    537,500      1,562,500   $  4,165,525  $  12,109,375
                                                                 750,000(2)           --     4,500,000             --
Michael K. Hoover.....         100,000             446,800(3)    793,268         80,000      5,876,388        356,000
Dennis Drislane.......              --                  --            --             --             --             --
Pavan Nigam...........              --                  --        36,458        413,542        255,206      1,757,294
Charles Saunders......              --                  --       111,160        288,840        861,490      1,908,510
</TABLE>
 
- ---------
 
(1) Based on a value of $3.55 per share, the fair market value of the common
    stock at June 2, 1998 as determined by the Board of Directors, minus the
    exercise price.
 
(2) Represents shares issuable upon exercise of a warrant issued to Mr. Long
    upon commencement of his employment with Healtheon. See "--Employment
    Agreements."
 
(3) Based on value of $4.50 per share, the fair market value of the common stock
    at July 8, 1998 as determined by the Board of Directors, minus the exercise
    price.
 
    Except in the case of Mr. Hoover, options shown above were granted under the
1996 Stock Plan and vest at a rate of 25% of the shares on the first anniversary
of the date of grant and 1/48 of the shares each month thereafter. An option to
purchase 80,000 shares of common stock held by Mr. Hoover was granted under the
1996 Stock Plan and vests as is described above. Mr. Hoover also holds options
to purchase 793,268 shares granted under the ActaMed 1992, 1993 Class B Common
and 1994 Stock Option Plans. These options were assumed by Healtheon upon the
consummation of the acquisition of ActaMed.
 
EMPLOYMENT AGREEMENTS
 
    Healtheon's ActaMed subsidiary has an employment agreement with Michael K.
Hoover, Healtheon's President. The agreement provides for a base salary of
$85,000, and imposes a covenant not to compete upon Mr. Hoover for a period of
one year following the termination of his employment.
 
    In July 1997, Healtheon and Mr. Long entered into an employment agreement
pursuant to which Mr. Long became the President and Chief Executive Officer of
Healtheon. Healtheon granted Mr. Long an option to purchase 2,500,000 shares of
common stock, 25% of which vested immediately, and the remainder of which vests
ratably each month during the second through the fourth year of his employment.
In addition, Mr. Long purchased 250,000 shares for $500,000, $499,750 of which
was represented by a promissory note to Healtheon, and was issued a warrant to
purchase an additional 750,000 shares at an exercise price of $2.00 per share.
The shares issuable upon exercise of this warrant are subject to a right of
repurchase commencing on Mr. Long's employment start date and lapsing as to
31,250 shares each month. The employment agreement provides that should Mr. Long
leave Healtheon because he is no longer offered a position with similar
responsibility due to a change of control of Healtheon, Mr. Long's option vests
immediately as to 625,000 shares and Healtheon's repurchase right lapses.
Additionally, if Healtheon terminates Mr. Long's employment without cause, he
will receive six months' salary in installments, his option will vest
immediately as to 625,000 shares and Healtheon's repurchase right will lapse.
 
                                       55
<PAGE>
EMPLOYEE BENEFIT PLANS
 
    1996 STOCK PLAN.  In February 1996 the Board adopted, and Healtheon's
stockholders approved, the 1996 Plan. Healtheon initially reserved for issuance
9,000,000 shares of common stock under the 1996 Plan. In March 1998, the Board
and the stockholders each approved an amendment to the 1996 Plan to increase the
number of shares of common stock reserved under the plan to 10,000,000 shares.
In July 1998, the Board approved, and in October 1998 the stockholders approved,
an amendment to increase the number of shares of common stock issuable under the
1996 Plan to 15,000,000 shares plus annual increases equal to the lesser of (1)
5% of the outstanding shares or (2) a lesser amount determined by the Board. In
January 1999, an additional 3,107,321 shares were reserved for issuance under
the 1996 Plan under the annual increase provision. In February 1999, the Board
and the stockholders approved an amendment to limit the automatic annual
increase provision to a maximum of 9,000,000 shares. In February 1999, the Board
and the stockholders also approved an amendment to increase the number of shares
reserved for issuance under the 1996 Plan by an additional 1,000,000 shares.
Unless terminated sooner, the 1996 Plan will terminate automatically in February
2006. The 1996 Plan provides for the discretionary grant of incentive stock
options, within the meaning of Section 422 of the Internal Revenue Code of 1986,
the "Code," to employees and for the grant of nonstatutory stock options and
stock purchase rights, "SPRs," to employees, directors and consultants. The 1996
Plan also provides for annual grants of options to purchase 5,000 shares of
common stock to each of the outside directors.
 
    The 1996 Plan may be administered by the Board or a committee of the Board
(as applicable, the "Administrator"). The Administrator has the power to
determine the terms of the options or SPRs granted, including the exercise price
of the options or SPRs, the number of shares subject to each option or SPR, the
exercisability thereof, and the form of consideration payable upon such
exercise. In addition, the Administrator has the authority to amend, suspend or
terminate the 1996 Plan, provided that no share of common stock previously
issued and sold or any option previously granted under the 1996 Plan is
affected.
 
    The exercise price of all incentive stock options granted under the 1996
Plan must be at least equal to the fair market value of the common stock on the
date of grant. The exercise price of nonstatutory stock options and SPRs granted
under the 1996 Plan is determined by the Administrator, but with respect to
nonstatutory stock options intended to qualify as "performance-based
compensation" within the meaning of Section 162(m) of the Code, the exercise
price must be at least equal to the fair market value of the common stock on the
date of grant. With respect to any participant who owns stock possessing more
than 10% of the voting power of all classes of Healtheon's outstanding capital
stock, the exercise price of any incentive stock option granted must be at least
equal 110% of the fair market value on the grant date and its term must not
exceed five years. The term of all other options granted under the 1996 Plan may
not exceed ten years. Options generally vest as to 25% at the end of the first
year and monthly thereafter over a period of three years so that the entire
option is vested after four years, based upon the optionee's continued
employment or consulting relationship with Healtheon.
 
    In the case of SPRs, unless the Administrator determines otherwise, the
restricted stock purchase agreement will grant Healtheon a repurchase option
exercisable upon the voluntary or involuntary termination of the purchaser's
employment or consulting relationship with Healtheon for any reason, including
death or disability. The purchase price for shares repurchased pursuant to a
restricted stock purchase agreement must be the original price paid by the
purchaser and may be paid by cancellation of any indebtedness of the purchaser
to Healtheon. The repurchase option will lapse at a rate determined by the
Administrator.
 
    Options and SPRs granted under the 1996 Plan are generally not transferable
by the optionee, and each option and SPR is exercisable during the lifetime of
the optionee only by the optionee. Options granted under the 1996 Plan must
generally be exercised within 30 days after the end of optionee's status as an
employee, director or consultant of Healtheon, or within one year after such
optionee's termination by disability or death, respectively, but in no event
later than the expiration of the option's term.
 
                                       56
<PAGE>
    The 1996 Plan provides that, in the event of a merger of Healtheon with or
into another corporation, each outstanding option and SPR must be assumed or an
equivalent option substituted by the successor corporation. If the outstanding
options and SPRs are not assumed or substituted by the successor corporation,
the outstanding options and SPRs will terminate.
 
    ACTAMED STOCK OPTION PLANS.  In connection with its acquisition of ActaMed
in a merger, Healtheon assumed the outstanding options of ActaMed under the
following ActaMed stock option plans (collectively, the "ActaMed Plans"):
ActaMed Corp. 1992 Stock Option Plan, ActaMed Corp. 1993 Class B common stock
Option Plan, ActaMed Corp. 1994 Stock Option Plan, ActaMed Corp. 1995 Stock
Option Plan, ActaMed Corp. 1996 Stock Option Plan, ActaMed Corp. 1997 Stock
Option Plan and ActaMed Corp. 1996 Director Stock Option Plan. The following
options held by directors and executive officers of Healtheon were assumed by
Healtheon: options to purchase 1,424,216 shares of ActaMed common stock held by
Michael Hoover, options to purchase 250,000 shares of ActaMed common stock held
by Nancy Ham, options to purchase 80,000 shares of ActaMed common stock held by
J. Philip Hardin, and options to purchase 220,000 shares of ActaMed common stock
held by John R. Hughes, Jr. As a result of the merger, each option to purchase
shares of ActaMed common stock now represents an option to purchase a number of
shares of Healtheon common stock equal to .6272 times the number of shares of
ActaMed common stock originally subject to the option at the per share exercise
price equal to the original per share exercise price divided by .6272. Healtheon
will make no further grants under the ActaMed Plans. However, each assumed
ActaMed option continues to have and remains subject to substantially the terms
and conditions of the applicable ActaMed Plan under which such option was
originally granted as in effect immediately prior to the merger.
 
    Generally, options granted under the ActaMed Plans will automatically
terminate ten years following their issuance. Options granted under the ActaMed
Plans generally are not transferable by the optionee, and must generally be
exercised within 30 days after the end of the optionee's status as an employee
or consultant of Healtheon or within 90 days after such optionee's termination
by disability or death, respectively, but in no event later than the expiration
of the option's term. Generally, in the event of any merger, sale of stock,
consolidation, liquidation, recapitalization, reclassification, stock split up,
combination of shares, share exchange, stock dividend, or transaction having a
similar effect, where Healtheon does not remain in existence, the Administrator
may (1) declare that all ActaMed options shall vest in full and be exercisable
for a period of thirty (30) days following written notice from the
Administrator, after which all ActaMed options shall terminate, (2) provide that
all ActaMed options shall be assumed by the successor corporation, or (3)
provide for a combination of (1) and (2).
 
    1998 EMPLOYEE STOCK PURCHASE PLAN.  Healtheon's 1998 Employee Stock Purchase
Plan, or the "1998 Purchase Plan," was adopted by the Board in September 1998,
and approved by the stockholders in October 1998. A total of 1,000,000 shares of
common stock has been reserved for issuance under the 1998 Purchase Plan, plus
annual increases equal to the lesser of (1) 500,000 shares, (2) .5% of the
outstanding shares on such date or (3) a lesser amount determined by the Board.
 
    The 1998 Purchase Plan contains consecutive, overlapping, twenty-four month
offering periods. Each offering period includes four six-month purchase periods.
The offering periods generally start on the first trading day on or after May 1
and November 1 of each year, except for the first such offering period which
commences on the first trading day on or after the effective date of this
offering and ends on the last trading day on or before October 31, 2000.
 
    Employees are eligible to participate if they are employed by Healtheon or
any participating subsidiary for at least 20 hours per week and more than five
months in any calendar year. However, an employee may not be granted an option
to purchase stock under the 1998 Purchase Plan if the employee (1) immediately
after grant would own stock possessing 5% or more of the total combined voting
power or value of all classes of the capital stock of Healtheon, or (2) holds
rights to purchase stock under any employee stock purchase plans of Healtheon
that together accrue at a rate which exceeds $25,000 worth of
 
                                       57
<PAGE>
stock for each calendar year. The 1998 Purchase Plan permits each participant to
purchase common stock through payroll deductions of up to 15% of the
participant's "compensation." Compensation is defined as the participant's base
straight time gross earnings and commissions but excludes payments for overtime,
shift premium, incentive compensation, incentive payments, bonuses and other
compensation. The maximum number of shares a participant may purchase during a
single purchase period is 5,000 shares.
 
    Amounts deducted and accumulated by the participant are used to purchase
shares of common stock at the end of each purchase period. The price of stock
purchased under the 1998 Purchase Plan is 85% of the lower of the fair market
value of the common stock (1) at the beginning of the offering period or (2) at
the end of the purchase period. In the event the fair market value at the end of
a purchase period is less than the fair market value at the beginning of the
offering period, the participants will be withdrawn from the current offering
period following exercise and automatically re-enrolled in a new offering
period. The new offering period will use the lower fair market value as of the
first date of the new offering period to determine the purchase price for future
purchase periods. Participants may end their participation at any time during an
offering period, and they will be paid their payroll deductions to date.
Participation ends automatically upon termination of employment with Healtheon.
 
    Rights granted under the 1998 Purchase Plan are not transferable by a
participant other than by will or the laws of descent and distribution. The 1998
Purchase Plan provides that, in the event of a merger of Healtheon with or into
another corporation or a sale of substantially all of Healtheon's assets, each
outstanding option may be assumed or substituted for by the successor
corporation. If the successor corporation refuses to assume or substitute for
the outstanding options, the offering period then in progress will be shortened
and a new exercise date will be set. The 1998 Purchase Plan will terminate in
2008. The Board has the authority to amend or terminate the 1998 Purchase Plan,
except that no amendment or termination may adversely affect any outstanding
options under the 1998 Purchase Plan. The Board may alter the purchase price for
any offering period or shorten an offering period at any time without consent of
the stockholders or of any participants.
 
    401(K) PLAN.  Healtheon participates in a tax-qualified employee savings and
retirement plan, or the "401(k) Plan," which covers all of Healtheon's full-time
employees who have completed three months of service. Under the 401(k) Plan,
eligible employees may defer up to 20% of their pre-tax earnings, subject to the
Internal Revenue Service's annual contribution limit. The 401(k) Plan permits
additional discretionary matching contributions by Healtheon on behalf of all
participants in the 401(k) Plan in such a percentage amount as may be determined
annually by the Board. To date, Healtheon has made no matching contributions.
The 401(k) Plan is intended to qualify under Section 401 of the Code, as
amended, so that contributions by employees or by Healtheon to the 401(k) Plan,
and income earned on plan contributions, are not taxable to employees until
withdrawn from the 401(k) Plan, and income earned on plan contributions, are not
taxable to employees until withdrawn from the 401(k) Plan, and so that
contributions by Healtheon, if any, will be deductible by Healtheon when made.
The trustee under the 401(k) Plan, at the direction of each participant, invests
the assets of the 401(k) Plan in any of a number of investment options.
 
                                       58
<PAGE>
                              CERTAIN TRANSACTIONS
 
    Since December 26, 1995, Healtheon's inception date, there has not been nor
is there currently proposed any transaction or series of similar transactions to
which Healtheon or any of its subsidiaries was or is to be a party in which the
amount involved exceeds $60,000 and in which any director, executive officer,
holder of more than 5% of the common stock of Healtheon or any member of the
immediate family of any of the foregoing persons had or will have a direct or
indirect material interest other than (1) compensation agreements and other
arrangements, which are described where required in "Management," and (2) the
transactions described below.
 
ACTAMED CORPORATION ACQUISITION
 
    On May 19, 1998, Healtheon acquired ActaMed in a merger. Pursuant to the
merger, Healtheon issued 23,271,355 shares of its common stock in exchange for
all of the issued and outstanding capital stock of ActaMed, and assumed all
options to purchase ActaMed common stock. The merger was treated as a tax-free
reorganization and as a "pooling-of-interests" transaction for accounting and
financial reporting purposes. All of the then outstanding shares of preferred
stock of Healtheon were converted into shares of common stock of Healtheon upon
the consummation of the merger.
 
    Healtheon and certain stockholders of Healtheon who together hold a majority
of the outstanding shares of common stock of Healtheon entered into a Voting
Agreement in connection with the merger, or the "Voting Agreement." Among other
things, the Voting Agreement requires each of the signatories thereto to vote
its shares in favor of the election of four directors nominated by those
signatories who were ActaMed shareholders prior to the merger and four directors
nominated by those signatories who were Healtheon stockholders prior to the
merger. The Voting Agreement terminates upon the consummation of this offering.
 
TRANSACTIONS WITH DIRECTORS, EXECUTIVE OFFICERS AND 5% STOCKHOLDERS
 
    1996 SERIES A PREFERRED STOCK.  On January 26, 1996, Healtheon sold
10,285,000 shares of its Series A preferred stock for $.50 per share. The
purchasers of the Series A preferred stock included, among others:
 
    - Dr. James H. Clark--3,500,000 shares;
 
    - Kleiner Perkins Caufield & Byers VII--2,999,500 shares;
 
    - KPCB VII Founders Fund--325,500 shares;
 
    - KPCB Life Sciences Zaibatsu Fund II--175,000 shares; and
 
    - New Enterprise Associates VI, Limited Partnership, or "New Enterprise
      Associates VI"--2,000,000 shares.
 
    KPCB VII Founders Fund, KPCB Life Sciences Zaibatsu Fund II and Kleiner
Perkins Caufield & Byers VII, along with KPCB VII Associates and KPCB Java Fund,
are affiliated entities. L. John Doerr, a director of Healtheon, is a general
partner of KPCB VII Associates and the general partner of KPCB Life Sciences
Zaibatsu Fund II. Mr. Doerr disclaims beneficial ownership of the securities
held by such entities except for his proportional interest in the entity. C.
Richard Kramlich, a director of Healtheon, is a general partner of New
Enterprise Associates VI. Mr. Kramlich disclaims beneficial ownership of the
securities held by that entity except for his proportional interest in the
entity.
 
    COMMON STOCK.  On January 26, 1996, Healtheon sold 1,000,000 shares of its
common stock for $.05 per share. The purchasers of the common stock included:
 
    - Dr. Clark--500,000 shares;
 
    - Kleiner Perkins Caufield & Byers VII--428,500 shares;
 
    - KPCB VII Founders Fund--46,500 shares; and
 
    - KPCB Life Sciences Zaibatsu Fund II--25,000 shares.
 
                                       59
<PAGE>
    SERIES B PREFERRED STOCK AND WARRANTS.  On October 1, 1996, Healtheon sold
3,000,000 shares of its Series B preferred stock for $2.00 per share. The
purchasers of the Series B preferred stock included, among others:
 
    - Dr. Clark--1,125,000 shares;
 
    - Kleiner Perkins Caufield & Byers VII--1,068,750 shares;
 
    - KPCB Life Sciences Zaibatsu Fund II--56,250 shares; and
 
    - New Enterprise Associates VI--500,000 shares.
 
    In related transactions, on November 1, 1996, Healtheon issued a warrant to
purchase 1,000,000 shares of Series B preferred stock with an exercise price of
$2.00 per share to Clark Ventures, as an incentive for Dr. Clark to continue to
provide services to Healtheon. Clark Ventures subsequently exercised its warrant
on May 1, 1998 for an aggregate purchase price of $2.0 million. Clark Ventures
is controlled by Dr. Clark.
 
    Also on November 1, 1996, Healtheon issued a warrant to purchase 1,000,000
shares of Series B preferred stock at an exercise price of $2.00 per share to
KPCB VII Associates, in consideration for services provided to Healtheon by
David Schnell, a former general partner of KPCB, in his capacity as President
and CEO. The warrant issued to KPCB VII Associates was valued at $504,900.
 
    On July 11, 1997 Healtheon issued 250,000 shares of Series B preferred stock
for a purchase price of $.5 million and a warrant to purchase 750,000 shares of
Series B Stock with an exercise price of $2.00 per share to W. Michael Long. See
"--Employment Agreements." In order to purchase the 250,000 shares of preferred
stock, Mr. Long borrowed $499,750 from Healtheon pursuant to a one-year
interest-free full recourse promissory note. The note was paid in full on June
30, 1998.
 
    BRIDGE FINANCING.  Between April 15, 1997 and May 6, 1997, Healtheon
borrowed an aggregate of $2.0 million at an annual interest rate of 6% pursuant
to promissory notes, each of which included a right to receive certain Series B
preferred stock warrants at the time of repayment or upon cancellation of the
note in a bridge financing transaction, or the "Bridge Financing." The lenders
in the Bridge Financing included, among others:
 
    - Dr. Clark--$765,750;
 
    - Kleiner Perkins Caufield & Byers VII--$727,463;
 
    - KPCB Life Sciences Zaibatsu Fund II--$38,288; and
 
    - New Enterprise Associates VI--$312,500.
 
    On July 1, 1997 the promissory notes were cancelled in consideration for the
issuance of Series C preferred stock, as described below, and the Series B
preferred stock warrants were issued as follows:
 
    - Dr. Clark received a warrant to purchase 17,229 shares;
 
    - Kleiner Perkins Caufield & Byers VII received a warrant to purchase 27,891
      shares;
 
    - KPCB Life Sciences Zaibatsu Fund II received a warrant to purchase 1,468;
      and
 
    - New Enterprise Associates VI received a warrant to purchase 11,979 shares.
 
    All of the Series B Warrants have an exercise price of $2.00 per share. Dr.
Clark subsequently exercised his warrant on May 1, 1998 for an aggregate
purchase price of $34,458.
 
    SERIES C PREFERRED STOCK.  On July 1, 1997, Healtheon sold 2,400,000 shares
of its Series C preferred stock for $2.50 per share. The purchasers of the
Series C preferred stock included, among others:
 
    - Dr. Clark--612,600 shares for a purchase price of $1.5 million, including
      cancellation of the $765,750 promissory note given in the Bridge Financing
      discussed above;
 
    - Kleiner Perkins Caufield & Byers VII--290,985 shares for cancellation of
      the $727,463 in promissory notes given in the Bridge Financing discussed
      above;
 
    - KPCB Java Fund--306,300 shares for a purchase price of $765,750;
 
                                       60
<PAGE>
    - KPCB Life Sciences Zaibatsu Fund II--15,315 shares for cancellation of the
      $38,288 in promissory note given in the Bridge Financing discussed above;
      and
 
    - New Enterprise Associates VI--250,000 shares for a purchase price of
      $625,000 including cancellation of the $312,500 promissory note given in
      the Bridge Financing discussed above.
 
    SERIES D PREFERRED STOCK.  Between October 17, 1997 and December 19, 1997,
Healtheon sold 4,807,692 shares of its Series D preferred stock for $5.20 per
share. The purchasers of the Series D preferred stock included, among others:
 
    - Clark Ventures--1,730,769 shares;
 
    - Kleiner Perkins Caufield & Byers VII--432,693 shares;
 
    - KPCB Java Fund--480,769 shares;
 
    - KPCB Life Sciences Zaibatsu Fund II--48,077 shares;
 
    - Kathy Clark--96,154 shares;
 
    - Michael James Clark Trust--96,154 shares; and
 
    - New Enterprise Associates VI, Limited Partnership--576,923 shares.
 
    Kathy Clark and Michael James Clark are adult children of Dr. Clark.
 
    On May 19, 1998, pursuant to the ActaMed merger, each outstanding share of
preferred stock of Healtheon converted into one share of common stock and each
outstanding warrant to purchase shares of Healtheon's preferred stock converted
into a warrant to purchase shares of Healtheon's common stock.
 
    1998 SERIES A PREFERRED STOCK.  On November 3, 1998 and November 6, 1998
Healtheon sold an aggregate of 7,683,341 shares of its Series A preferred stock
for $6.00 per share. Among the purchasers were the following 5% stockholders and
entities affiliated with directors of Healtheon, who purchased the number of
shares indicated:
 
    - Atherton Properties Partnership, LP, an entity controlled by Dr. Clark and
      affiliated with Kathy Clark and Michael Clark--166,667 shares;
 
    - Kathy Clark--166,667 shares;
 
    - Michael James Clark Trust--166,667 shares;
 
    - HLM Partners VII, LP, of which UnitedHealth Group is a limited
      partner--166,667 shares;
 
    - KPCB Java Fund--416,667 shares;
 
    - Kleiner Perkins Caufield & Byers--375,000 shares;
 
    - KPCB Life Sciences Zaibatsu Fund II--41,667 shares;
 
    - Monaco Partners, LP, an entity wholly controlled by Dr. Clark--2,850,000
      shares; and
 
    - New Enterprise Associates VI, LP--416,667 shares.
 
Holders of Series A preferred stock have agreed that each share of Series A
preferred stock will convert into one share of common stock upon the closing of
this offering.
 
    SADLER RELATIONSHIPS.  On November 21, 1996, ActaMed entered into an Amended
and Restated Development Agreement with The SFA Limited Partnership, or "SFA,"
under which ActaMed granted SFA a license to ActaMed's object broker technology
that supports the GMPI functionality. SFA is controlled by P. E. Sadler, a
director of Healtheon. SFA was given the right to use ActaMed's object broker
technology outside the healthcare industry and must pay royalties on any
revenues that would be derived from its use. This agreement expires in November
2001. To date, no royalties have become payable to Healtheon or ActaMed as a
result of this agreement.
 
    In September 1997, ActaMed received a loan from NationsBank, N.A. in the
aggregate principal amount of $2.1 million, all of which was personally
guaranteed by P. E. Sadler, a director of Healtheon. As a result of ActaMed's
pledging a note receivable from IBM to NationsBank, N.A. in November 1997, Mr.
Sadler was released from the guarantee. In December 1997, ActaMed obtained a
line of credit in the aggregate principal amount of $2.3 million from
NationsBank, N.A. In exchange for a personal guarantee of this line of credit by
Mr. Sadler, ActaMed granted to Mr. Sadler a security interest in all of its
tangible
 
                                       61
<PAGE>
assets other than the IBM note receivable. Upon the completion of the
acquisition of ActaMed by Healtheon, Mr. Sadler's guarantee was released. This
line of credit was repaid by Healtheon on July 31, 1998.
 
    From 1995 through June 1998, up to three companies affiliated with Mr.
Sadler had agreements with ActaMed whereby ActaMed provided office space, phone
facilities and computer network support. ActaMed was paid approximately $273,000
in 1995, $245,000 in 1996, $114,000 in 1997 and $51,000 in 1998 under those
agreements.
 
CERTAIN BUSINESS RELATIONSHIPS
 
    SMITHKLINE LABS
 
    1997-1998 ASSET PURCHASE AGREEMENTS.  Prior to the acquisition of ActaMed by
Healtheon, ActaMed entered into a series of agreements, the "SmithKline
Agreements," with SmithKline Labs, which agreements were assumed by Healtheon in
the ActaMed merger. Under the SmithKline Agreements, ActaMed agreed to purchase
certain assets, or the "SmithKline Assets," located in four geographic regions,
received a technology license relating to the SmithKline Assets and agreed to
provide certain continuing development and network services to SmithKline Labs.
In December 1997, SmithKline Labs transferred a portion of the SmithKline Assets
from the first region to ActaMed in exchange for $2.0 million in cash and
3,695,652 shares of ActaMed preferred stock. The shares of ActaMed preferred
stock issued to SmithKline were converted into 2,317,913 shares of Healtheon's
common stock in connection with the ActaMed merger. In March 1998, SmithKline
Labs transferred the SmithKline Assets from the second region to ActaMed in
exchange for 1,217,391 shares of ActaMed preferred stock. Those shares were
converted into 763,548 shares of Healtheon's common stock in connection with the
ActaMed merger. In June 1998, SmithKline Labs transferred SmithKline Assets from
the remaining two regions to Healtheon in exchange for 1,336,209 shares of
common stock.
 
    SERVICES AGREEMENT.  Also pursuant to one of the SmithKline Agreements, the
"Services Agreement," Healtheon will perform laboratory test order and results
services to providers utilizing SmithKline Labs' laboratory services through
SCAN. SmithKline Labs is obligated to pay Healtheon a minimum of approximately
$10.0 million in 1998 for laboratory test orders and results transactions.
SmithKline Labs may be required to pay Healtheon certain additional fees for
transactions processed by Healtheon in the event the number of providers
accessing SmithKline Labs' laboratory services through SCAN increases.
SmithKline Labs paid Healtheon $7.1 million in service and transaction fees
during the first nine months of 1998 under the Services Agreement. The Services
Agreement is effective through December 2002, and provides for automatic
successive two-year renewals, subject to each party's right to elect not to
renew the agreement no later than 180 days, in the case of SmithKline Labs, or
360 days, in the case of Healtheon, prior to the end of a term. In the event
that Healtheon gives notice of non-renewal, SmithKline Labs will be entitled to
continued to receive long-term order entry and results reporting services from
Healtheon on a per transaction pricing basis or, in the alternative, may require
Healtheon to develop a service for SmithKline that duplicates the services
Healtheon had been providing under the Services Agreement.
 
    Also under the Services Agreement, SmithKline Labs is entitled, no more than
once in any three consecutive month periods, to request that Healtheon engage in
certain exclusive development work for SmithKline Labs. SmithKline Labs has
agreed to use reasonable efforts to use Healtheon as its "preferred provider" of
electronic eligibility verification and claims processing services. The Services
Agreement provides that the parties will negotiate new rates as of January 1,
2001 and each two years after that date. The Services Agreement states that the
renegotiated rates must be competitive with the marketplace and must be no
higher than the lowest fees charged by Healtheon to similarly situated
customers. See "Management's Discussion and Analysis--Overview" and Note 3 of
Notes to Consolidated Financial Statements.
 
                                       62
<PAGE>
    NONCOMPETE LETTER.  In May 1998, Healtheon and SmithKline Labs entered into
a letter agreement under which Healtheon is obligated not to compete with
SmithKline Labs in the business of disease management, and has agreed to
exclusively promote SmithKline Labs' disease management products and services so
long as SmithKline continues to promote Healtheon as its preferred vendor.
Healtheon also agreed that, in the event it performs development work related to
a disease management program for one of its customers or itself, it will pay 50%
of the profits from that development work to SmithKline Labs.
 
    1999 ASSET PURCHASE AGREEMENT.  In December 1998, Healtheon agreed to
purchase, and in January 1999, Healtheon purchased certain assets used by
SmithKline Labs to provide laboratory results delivery services in exchange for
$2.0 million in cash and approximately 1.8 million shares of Healtheon's common
stock. Healtheon and SmithKline Labs entered into a related services agreement
under which Healtheon will provide certain electronic laboratory results
delivery services to approximately 20,000 provider sites, in addition to the
sites currently served through the SCAN service. The services agreement has a
five year term with anticipated revenues of $17.0 to $18.0 million in the first
year. Healtheon does not expect this arrangement to significantly contribute to
earnings in the near term. Profitability will depend on Healtheon's ability to
use these assets to provide results delivery services for non-SmithKline labs
and to transition these provider sites to Healtheon's Internet-based services.
On February 9, 1999, SmithKline Beecham announced that it has agreed to sell
SmithKline Labs to Quest Diagnostics, Incorporated.
 
    UNITED HEALTHCARE
 
    EDI SERVICES ACQUISITION.  In March 1996, ActaMed acquired EDI Services, a
wholly-owned subsidiary of UnitedHealth Group, which had been formed by
UnitedHealth Group to deliver the ProviderLink service to UnitedHealth Group's
provider network. In exchange for EDI, ActaMed issued UnitedHealth Group
10,344,828 shares of ActaMed preferred stock valued at $21.0 million which were
converted into 6,488,276 shares of Healtheon's common stock in connection with
the merger.
 
    SERVICES AGREEMENT.  In April 1996, ActaMed also entered into a Services and
License Agreement with UnitedHealth Group that granted UnitedHealth Group a
license to certain ActaMed technology and granted ActaMed the responsibilities
of managing the ProviderLink service and of providing other information
technology services to UnitedHealth Group. UnitedHealth Group pays Healtheon
fees based on the number of ProviderLink sites in use and transactions
processed. In 1996 and 1997, UnitedHealth Group paid ActaMed approximately $4.2
million and $7.3 million, respectively, related to services, transaction and
license fees. In the first nine months of 1998, ActaMed, prior to the merger,
and Healtheon were paid an aggregate of $7.2 million. Healtheon is also
obligated to provide certain support and maintenance services to UnitedHealth
Group. The Services and License Agreement is effective through March 2001
subject to earlier termination in the event Healtheon fails to meet certain
network performance standards or otherwise breaches its material obligations
under the UnitedHealth Group Agreement. The Service and License Agreement
provides that two years after the date of the agreement the parties will agree
on new prices that will be competitive with the marketplace. Healtheon and
UnitedHealth Group are negotiating these new prices, and Healtheon anticipates
that the new prices will reduce the rates paid by UnitedHealth Group. See
"Management's Discussion and Analysis--Overview" and Note 2 of Notes to
Consolidated Financial Statements. UnitedHealth Group is a principal stockholder
of Healtheon and Dr. William McGuire, Chief Executive Officer and Chairman of
UnitedHealth Group, is a director of Healtheon.
 
    HLM NOTE.  In February 1998, ActaMed issued a one-year promissory note in
the aggregate principal amount of $2.0 million to HLM Partners VII, L.P., or
"HLM," which bore interest at a rate of 10% per annum. UnitedHealth Group was a
limited partner of HLM and a director of United HealthCare, was a partner of
HLM. HLM was also a stockholder of ActaMed. Both UHC and HLM are stockholders of
Healtheon. This note was repaid at the time of the merger.
 
                                       63
<PAGE>
                             PRINCIPAL STOCKHOLDERS
 
    The following table sets forth certain information with respect to the
beneficial ownership of Healtheon's common stock as of November 30, 1998 and as
adjusted to reflect the sale of the shares of common stock in this offering by:
(1) each person who is known by Healtheon to beneficially own more than 5% of
Healtheon's common stock, (2) each director of Healtheon, (3) each of the Named
Executive Officers and (4) all directors and executive officers of Healtheon as
a group.
 
    The number and percentage of shares beneficially owned are based on
62,195,893 shares of common stock outstanding as of November 30, 1998, assuming
conversion of all outstanding shares of preferred stock into common stock.
Beneficial ownership is determined under the rules and regulations of the
Securities and Exchange Commission. Shares of common stock subject to options or
warrants that are currently exercisable or exercisable within 60 days of
November 30, 1998 are deemed to be outstanding and beneficially owned by the
person holding the options or warrants for the purpose of computing the number
of shares beneficially owned and the percentage ownership of that person. The
shares subject to options or warrants held by a person are not deemed to be
outstanding for the purpose of computing the percentage ownership of any other
person. Except as indicated in the footnotes to this table, and subject to
applicable community property laws, these persons have sole voting and
investment power with respect to all shares of Healtheon's common stock shown as
beneficially owned by them. The table assumes the U.S. Underwriters'
over-allotment option to purchase 750,000 shares of common stock is not
exercised. Percentage ownership figures after the offering do not include shares
that may be purchased by each person in the offering.
 
<TABLE>
<CAPTION>
                                                                                                 PERCENTAGE OF SHARES
                                                                                                  BENEFICIALLY OWNED
                                                                          NUMBER OF SHARES   ----------------------------
                                                                            BENEFICIALLY        BEFORE          AFTER
NAME OF BENEFICIAL OWNER                                                        OWNED          OFFERING       OFFERING
- ------------------------------------------------------------------------  -----------------  -------------  -------------
<S>                                                                       <C>                <C>            <C>
Entities associated with James H. Clark(1)..............................        11,502,265          18.5%          17.1%
Entities associated with UnitedHealth Group(2)..........................         8,936,687          14.4           13.3
  William W. McGuire, M.D.(2)...........................................         8,936,687          14.4           13.3
Entities associated with Kleiner Perkins Caufield & Byers(3)............         8,086,832          12.8           11.9
  L. John Doerr(3)......................................................         8,086,832          12.8           11.9
SmithKline Beecham Clinical Laboratories, Inc.(4).......................         6,251,003(4)         9.8           9.1
  Tadataka Yamada(4)....................................................         6,251,003(4)         9.8           9.1
P. E. Sadler(5).........................................................         5,001,993           8.0            7.4
Entities associated with New Enterprise Associates, L.P.(6).............         3,755,569           6.0            5.6
  C. Richard Kramlich(6)................................................         3,755,569           6.0            5.6
W. Michael Long(7)......................................................         1,937,500           3.1            2.8
Integral Capital Partners, L.P..........................................         1,255,129           2.0            1.9
Michael K. Hoover(8)....................................................           888,268           1.4            1.3
Dennis Drislane(9)......................................................           550,000             *              *
Pavan Nigam(10).........................................................           509,062             *              *
Thomas A. Jermoluk......................................................           333,334             *              *
Charles Saunders(11)....................................................           115,178             *              *
Laura D'Andrea Tyson....................................................                --            --             --
All officers and directors as a group (24 persons)(12)..................        49,469,829          73.1           68.1
</TABLE>
 
- ----------
 
*   Less than one percent
 
(1) Represents 166,667 shares held of record by Atherton Properties Partnership,
    LP, 4,000,000 shares held of record by Dr. Clark as trustee of the James H.
    Clark and Nancy Rutter Clark Revocable Trust, 1,017,229 shares held of
    record by Clark Ventures, 268,000 shares held of record by JHC Investments,
    LLC and 6,050,369 shares held of record by Monaco Partners, LP. Dr. Clark
    wholly controls Atherton Properties
 
                                       64
<PAGE>
    Partnership, LP, Clark Ventures, JHC Investments, LLC and Monaco Partners,
    LP. Dr. Clark is a director of Healtheon. The address for Dr. Clark is c/o
    Healtheon Corporation, 4600 Patrick Henry Drive, Santa Clara, CA 95054. The
    address for Clark Ventures and Monaco Partners, LP is 777 East Williams
    Street, Suite 201, Carson City, NV 89701.
 
(2) Represents 6,488,276 shares held of record by UnitedHealth Group, 502,069
    shares held of record by United HealthCare Services, Inc., a subsidiary
    thereof, 676,262 shares held of record by HLM Partners VII, L.P., of which
    UnitedHealth Group is a limited partner and 1,270,080 shares held of record
    by Validus, L.P., of which UnitedHealth Group is the sole limited partner.
    UnitedHealth Group disclaims beneficial ownership of shares held by both
    limited partnerships except to the extent of its pecuniary interests in the
    entities. Dr. McGuire, a director of Healtheon, is the President, Chief
    Executive Officer and Chairman of UnitedHealth Group. Dr. McGuire disclaims
    beneficial ownership of all shares held by UnitedHealth Group. UnitedHealth
    Group's address is 9900 Bren Road East, 300 Opus Center, Minnetonka, MN
    55343.
 
(3) Represents 5,500,863 shares held of record directly by Kleiner Perkins
    Caufield & Byers VII L.P. ("KPCB VII"), 1,203,736 shares held of record by
    KPCB Java Fund, and 352,874 shares held of record by KPCB Life Sciences
    Zaibatsu Fund II. Also represents 976,423 shares subject to warrants held of
    record by KPCB VII, and 52,936 shares subject to warrants held of record by
    KPCB Life Sciences Zaibatsu Fund II L.P., all of which are exercisable
    within 60 days of November 30, 1998. KPCB Life Sciences Zaibatsu Fund II and
    KPCB VII are wholly controlled by KPCB VII Associates, L.P. KPCB Java Fund
    is controlled by KPCB VIII Associates. L. John Doerr, a general partner of
    KPCB VIII Associates and KPCB VII Associates, L.P., is a director of
    Healtheon. Mr. Doerr disclaims beneficial ownership of shares held by these
    entities except to the extent of his pecuniary interest in the entities.
    Kleiner Perkins Caufield & Byers' address is 2750 Sand Hill Road, Menlo
    Park, CA 94025.
 
(4) Includes in the number of shares beneficially owned by SmithKline Labs and
    in the total number of outstanding shares of common stock 1,833,333 shares
    of common stock issued under a December 1998 Asset Purchase Agreement with
    SmithKline Labs. Dr. Yamada, a director of Healtheon, is President and
    Executive Director of SmithKline Beecham HealthCare Services and a director
    of SmithKline Beecham. SmithKline Labs' address is 1201 South Collegeville
    Road, Collegeville, PA 19426. Dr. Yamada disclaims beneficial ownership of
    all shares held by SmithKline Labs.
 
(5) Represents 2,975,140 shares held of record by P. E. Sadler and 2,026,853
    shares held of record by SFA Limited Partnership, of which P. E. Sadler is a
    general partner. Mr. Sadler is a director of Healtheon. Mr. Sadler's address
    is c/o Healtheon Corporation, 4600 Patrick Henry Drive, Santa Clara, CA
    95054.
 
(6) Represents 3,723,590 shares held of record directly by New Enterprise
    Associates VI, L.P., or "New Enterprise Associates VI," 11,979 shares
    subject to warrants held of record by New Enterprise Associates VI
    exercisable within 60 days of November 30, 1998, and 20,000 shares held of
    record by NEA Ventures 1996, L.P., which is controlled by New Enterprise
    Associates VI. Mr. Kramlich is a partner of New Enterprise Associates VI.
    Mr. Kramlich disclaims beneficial ownership of shares held by these entities
    except for his proportional interests in the entities. New Enterprise
    Associates VI's address is 1119 St. Paul Street, Baltimore, MD 21202.
 
(7) Includes 750,000 shares subject to a warrant held of record by Mr. Long and
    537,500 shares subject to options held of record by Mr. Long, in each case
    exercisable within 60 days of November 30, 1998. 187,500 shares underlying
    the warrant held by Mr. Long will remain subject to a right of repurchase by
    Healtheon 60 days after November 30, 1998. Mr. Long is the Chief Executive
    Officer and a director of Healtheon.
 
(8) Represents 92,500 shares held of record directly by Mr. Hoover, 2,500 shares
    held by Nicholas D. Hoover for which Mr. Hoover is custodian, and 793,268
    shares subject to options held of record by Mr. Hoover that are exercisable
    within 60 days of November 30, 1998. Mr. Hoover is the President and a
    director of Healtheon.
 
(9) Includes 343,750 shares held by Mr. Drislane that will remain subject to a
    right of repurchase by Healtheon 60 days after November 30, 1998.
 
(10) Includes 39,062 shares subject to options held of record by Mr. Nigam that
    are exercisable within 60 days of November 30, 1998. Also includes 121,875
    shares that will remain subject to a right of repurchase by Healtheon 60
    days after November 30, 1998. Mr. Nigam is the Vice President, Engineering
    of Healtheon.
 
(11) Represents 115,178 shares subject to options held of record by Mr. Saunders
    that are exercisable within 60 days of November 30, 1998. Mr. Saunders is
    the Vice President, Marketing and Consulting Services and Medical Director
    of Healtheon.
 
(12) Includes all shares described in the above footnotes and includes an
    additional 1,422,971 shares held by other executive officers, of which
    1,085,928 shares were outstanding as of November 30, 1998 and 337,043 shares
    are subject to options or warrants that are exercisable within 60 days of
    November 30, 1998.
 
                                       65
<PAGE>
                          DESCRIPTION OF CAPITAL STOCK
 
    The following summary of certain provisions of Healtheon's capital stock
describes all material provisions of Healtheon's Certificate of Incorporation
and Bylaws. This summary, however, does not purport to be complete and is
subject to, and qualified in its entirety by, the Certificate of Incorporation
and Bylaws, copies of which have been filed as exhibits to the Registration
Statement of which this prospectus is a part and by the provisions of applicable
law.
 
    As of November 30, 1998, there were 62,183,393 shares of common stock
outstanding, par value $0.0001 per share, assuming the conversion of all
outstanding shares of preferred stock into shares of common stock. Upon
consummation of this offering, 150,000,000 shares of common stock and 5,000,000
shares of preferred stock will be authorized.
 
COMMON STOCK
 
    The issued and outstanding shares of common stock are, and the shares of
common stock offered by this prospectus will be validly issued, fully paid and
nonassessable upon payment for the shares. The holders of outstanding shares of
common stock are entitled to receive dividends out of assets legally available
therefor at a time and in amounts as the Board may from time to time determine.
See "Dividend Policy." The shares of common stock are not convertible and the
holders thereof have no preemptive or subscription rights to purchase any
securities of Healtheon. Upon liquidation, dissolution or winding up of
Healtheon, the holders of common stock are entitled to receive pro rata the
assets of Healtheon that are legally available for distribution, after payment
of all debts and other liabilities. Each outstanding share of common stock is
entitled to one vote on all matters submitted to a vote of the stockholders,
including election of directors. There is no cumulative voting in the election
of directors.
 
PREFERRED STOCK
 
    Holders of Series A preferred stock have agreed that each outstanding share
of Series A preferred stock will be converted into one share of common stock
upon the closing of this offering. See Note 14 of Notes to Consolidated
Financial Statements for a description of the Series A preferred stock issued in
November 1998. Upon the closing of this offering, Healtheon's Certificate of
Incorporation will provide that preferred stock may be issued by Healtheon in
one or more series and that the Board has the authority, without further action
by the stockholders, to fix the rights, preferences and privileges thereof,
including dividend rights, conversion rights, voting rights, rights and terms of
redemption, liquidation preferences and sinking fund terms, any or all of which
may be greater than the rights of the common stock. The issuance of preferred
stock could adversely affect the voting power of holders of common stock and the
likelihood that such holders would receive dividend payments and payments upon
liquidation. The issuance of preferred stock could have the effect of decreasing
the market price of the common stock. The issuance of preferred stock may also
have the effect of delaying, deterring or preventing a change in control of
Healtheon. Healtheon has no present plans to issue any shares of preferred
stock.
 
WARRANTS
 
    As of November 30, 1998, Healtheon has outstanding warrants for the purchase
of 2,077,240 shares of common stock. Of these, warrants to purchase 1,794,718
shares of common stock have an exercise price of $2.00 and expire with respect
to 1,000,000 shares on November 1, 1999, with respect to 750,000 shares on July
10, 2000, and with respect to 44,718 shares on June 30, 2002. Warrants to
purchase 282,522 shares of common stock have an exercise price of $7.97, which
expire December 2001. In addition, in December 1998, as part of a service
agreement with a customer, Healtheon issued to the customer a warrant to
purchase 500,000 shares of common stock with an exercise price of $10.40 per
share, which expires on March 15, 2003.
 
                                       66
<PAGE>
REGISTRATION RIGHTS
 
    The holders of approximately 50,007,164 shares of common stock or their
permitted transferees are entitled to certain rights with respect to
registration of their shares, or the "Registrable Securities," under the
Securities Act. These shares are held by (1) purchasers of common stock at the
founding of Healtheon in December 1995, (2) purchasers of preferred stock of
Healtheon prior to its conversion into common stock in connection with the
acquisition of ActaMed, (3) certain former shareholders of ActaMed who received
shares of Healtheon's common stock pursuant to Healtheon's acquisition of
ActaMed and who had registration rights with respect to their shares of ActaMed
capital stock and (4) purchasers of the Series A preferred stock sold in
November 1998.
 
    At any time after 12 months following the effective date of this offering,
the holders of at least 40% of the Registrable Securities then outstanding may
require Healtheon to file a registration statement covering Registrable
Securities with an aggregate gross offering price of at least $10.0 million. In
addition, two years after this offering, holders of registrable securities may
require, on up to four separate occasions, that Healtheon register their shares
for public resale on Form S-3 or any successor form, provided Healtheon is
eligible to use Form S-3 or any such successor form. The value of the securities
to be so registered must be at least $1.0 million. Furthermore, in the event
Healtheon elects to register any of its shares of common stock or other
securities for purposes of effecting any public offering, the holders of
Registrable Securities are entitled to include their Registrable Securities in
the registration, subject however to the right of Healtheon to reduce the number
of shares proposed to be registered in view of market conditions. All expenses
in connection with any registration, other than underwriting discounts and
commissions, will be borne by Healtheon. Registration rights, other than the
right to require Healtheon to register shares on Form S-3 or any successor form,
will terminate at such time as Healtheon's shares are publicly traded and the
holder is entitled to sell all of its shares in any three-month period under
Rule 144 of the Securities Act. If Healtheon's stockholders with registration
rights cause a large number of securities to be registered and sold in the
public market, those sales could have an adverse effect on the market price for
Healtheon's common stock. If Healtheon were to initiate a registration and
include Registrable Securities because of the exercise of registration rights,
the inclusion of Registrable Securities could have an adverse effect on
Healtheon's ability to raise capital.
 
CERTAIN ANTI-TAKEOVER EFFECTS OF PROVISIONS OF HEALTHEON'S CERTIFICATE OF
  INCORPORATION AND BYLAWS AND OF DELAWARE LAW
 
    GENERAL.  Certain provisions of Delaware law and Healtheon's Certificate of
Incorporation and Bylaws could have the effect of making it more difficult for a
third party to acquire, or of discouraging a third party from acquiring, control
of Healtheon. Such provisions could limit the price that certain investors might
be willing to pay in the future for shares of Healtheon's common stock. These
provisions of Delaware law and the Certificate of Incorporation and Bylaws may
also have the effect of discouraging or preventing certain types of transactions
involving an actual or threatened change of control of Healtheon, including
unsolicited takeover attempts, even though such a transaction may offer
Healtheon's stockholders the opportunity to sell their stock at a price above
the prevailing market price.
 
    DELAWARE TAKEOVER STATUTE.  Following consummation of this offering,
Healtheon will be subject to the "business combination" provisions of Section
203 of the Delaware General Corporation Law. In general, those provisions
prohibit a publicly-held Delaware corporation from engaging in various "business
combination" transactions with any interested stockholder for a period of three
years after the date of the transaction in which the person became an interested
stockholder, unless:
 
    - the transaction is approved by the board of directors prior to the date
      the interested stockholder obtained interested stockholder status;
 
    - upon consummation of the transaction that resulted in the stockholder's
      becoming an interested stockholder, the stockholder owned at least 85% of
      the voting stock of the corporation outstanding at the time the
      transaction commenced, excluding for purposes of determining the number of
      shares
 
                                       67
<PAGE>
      outstanding those shares owned by (a) persons who are directors and also
      officers and (b) employee stock plans in which employee participants do
      not have the right to determine confidentially whether shares held subject
      to the plan will be tendered in a tender or exchange offer; or
 
    - on or subsequent to the date the business combination is approved by the
      board of directors and authorized at an annual or special meeting of
      stockholders by the affirmative vote of at least 66 2/3% of the
      outstanding voting stock that is not owned by the interested stockholder.
      A "business combination" is defined to include mergers, asset sales and
      other transactions resulting in financial benefit to a stockholder. In
      general, an "interested stockholder" is a person who, together with
      affiliates and associates, owns, or within three years, did own, 15% or
      more of a corporation's voting stock.
 
    The statute could prohibit or delay mergers or other takeover or change in
control attempts with respect to Healtheon and, accordingly, may discourage
attempts to acquire Healtheon.
 
    CERTIFICATE OF INCORPORATION AND BYLAWS.  Healtheon's Certificate of
Incorporation provides that any action to be taken by the stockholders of
Healtheon must be effected at an annual or special stockholder meeting and may
not be taken by written consent. Healtheon's Bylaws provide that special
meetings of the stockholders of Healtheon may be called by the Board or by the
President of Healtheon, or by one or more stockholders holding at least 10% of
the voting power of Healtheon's outstanding capital stock, or any persons as may
be authorized by the Certificate of Incorporation or the Bylaws (which currently
only give this authority to the Board). Healtheon's Bylaws also require advance
written notice by a stockholder of a proposal or director nomination that such
stockholder desires to present at an annual or special stockholders meeting. No
business other than that stated in the notice may be transacted at any special
meeting. These provisions will delay consideration of a stockholder proposal
until the next annual meeting unless a special meeting is called by the Board.
 
    Healtheon's Bylaws provide that the authorized number of directors may be
changed by an amendment to the Bylaws adopted by the Board or by the
stockholders. Vacancies on the Board may be filled either by holders of a
majority of Healtheon's voting stock or a majority of directors in office,
although less than a quorum. The Certificate of Incorporation and the Bylaws of
Healtheon also provide for a staggered Board. Under a staggered Board, each
director is designated to one of three categories. Each year the directors'
positions in one of the three categories are subject to election so that it
would take three years to replace the entire board, absent resignation or
premature expiration of a director's term, which may have the effect of
deterring a hostile takeover or delaying or preventing changes in control or
management of Healtheon.
 
LIMITATIONS ON LIABILITY AND INDEMNIFICATION OF OFFICERS AND DIRECTORS
 
    Healtheon's Certificate of Incorporation limits the liability of directors
to the fullest extent permitted by the Delaware law. In addition, the
Certificate of Incorporation and Bylaws provide that Healtheon will indemnify
directors and officers of Healtheon to the fullest extent permitted by Delaware
law. Healtheon intends to enter into separate indemnification agreements with
its directors and executive officers that provide these persons indemnification
protection in the event the Certificate of Incorporation is subsequently
amended.
 
TRANSFER AGENT AND REGISTRAR
 
    American Stock Transfer Trust Company has been appointed as transfer agent
and registrar for Healtheon's common stock.
 
LISTING
 
    The common stock has been accepted for quotation on the Nasdaq National
Market under the symbol "HLTH."
 
                                       68
<PAGE>
                        SHARES ELIGIBLE FOR FUTURE SALE
 
    Prior to this offering, there has been no public market for the common stock
of Healtheon. Future sales of substantial amounts of common stock in the public
market, or the perception that such sales may occur, could adversely affect
prevailing market prices.
 
    Upon consummation of the offering, Healtheon will have an aggregate of
67,195,893 shares of common stock outstanding, based on the number of shares of
common stock outstanding as of November 30, 1998, assuming conversion of all
outstanding Series A preferred stock into common stock on the closing of this
offering, no exercise of the U.S. underwriters over-allotment option and no
exercise of outstanding options and warrants. Of the 67,195,893 shares
outstanding after the offering, 5,658,184 shares, including the 5,000,000 shares
sold in this offering, will be freely tradable without restriction under the
Securities Act, except for any shares that may be purchased by "affiliates" of
Healtheon. Shares purchased by Healtheon's affiliates will be subject to the
volume and other limitations of Rule 144 of the Securities Act, or "Rule 144"
described below. As defined in Rule 144, an "affiliate" of an issuer is a person
who, directly or indirectly, through one or more intermediaries, controls, is
controlled by or is under common control with the issuer. Upon the expiration of
certain contractual "lock-up" restrictions described below, 52,254,368 shares
will be eligible for sale 180 days after the date of this prospectus, with
41,817,104 of such shares subject to the volume and other limitations of Rule
144. The remaining 9,283,341 shares will become eligible for sale at various
times after that date, including 7,683,341 shares that will become eligible for
resale between November 3 and November 6, 1999. All of these remaining shares
will be subject to the volume and other limitations of Rule 144. In addition,
the 1,833,333 shares issued to SmithKline Labs in January 1999 will become
eligible for sale on January 19, 2000, subject to the volume and other
limitations of Rule 144.
 
    Each of Healtheon's directors and officers and certain other stockholders of
Healtheon have agreed with Morgan Stanley & Co. Incorporated, for a period of
180 days after the date of this prospectus, not to:
 
    - offer, pledge, sell, contract to sell, sell any option or contract to
      purchase, purchase any option or contract to sell, grant any option, right
      or warrant to purchase, lend, or otherwise transfer or dispose of,
      directly or indirectly, any shares of common stock or any securities
      convertible into or exercisable or exchangeable for common stock; or
 
    - enter into any swap or other arrangement that transfers to another, in
      whole or in part, any of the economic consequences of ownership of the
      common stock, whether any such transaction described above is to be
      settled by delivery of common stock or other securities, in cash or
      otherwise.
 
Morgan Stanley & Co. Incorporated may choose to release some of these shares
from such restrictions prior to the expiration of the 180-day period "lock-up"
period, although it has no current intention of doing so.
 
    Under Rule 144 as currently in effect, beginning 90 days after the date of
this prospectus, a person who has beneficially owned restricted shares of common
stock for at least one year, including the holding period of any prior owner who
is not an affiliate, would be entitled to sell a number of the shares within any
three-month period equal to the greater of (1) 1% of the then outstanding shares
of the common stock or (2) the average weekly reported volume of trading of the
common stock on the Nasdaq National Market during the four calendar weeks
preceding such sale. Immediately after the offering, 1% of Healtheon's
outstanding shares of common stock would equal approximately 671,959 shares.
Under Rule 144, restricted shares are subject to manner of sale and notice
requirements and requirements as to the availability of current public
information concerning Healtheon. Under Rule 144(k), a person who is not deemed
to have been an affiliate at any time during the 90 days preceding a sale, and
who has beneficially owned the shares proposed to be sold for at least two
years, including the holding period of any prior owner who is not an affiliate,
is entitled to sell such shares without regard to the volume or other
limitations of Rule 144 just described.
 
                                       69
<PAGE>
    The holders of approximately 50,007,164 shares of common stock are also
entitled to certain rights with respect to registration of their shares of
common stock for offer or sale to the public. If the holders, by exercising
their registration rights, cause a large number of shares to be registered and
sold in the public market, the sales could have a material adverse effect on the
market price for Healtheon's common stock.
 
    Immediately after this offering, there will be options to purchase
approximately 11,827,385 shares of common stock outstanding, based on the number
of options outstanding as of November 30, 1998. Subject to the provisions of the
lock-up agreements described above, holders of these options may rely on the
resale provisions of Rule 701 under the Securities Act. Rule 701 permits
non-affiliates to sell their shares without having to comply with the volume,
holding period or other limitations of Rule 144 and permits affiliates to sell
their shares without having to comply with the holding period limitation of Rule
144, in each case beginning 90 days after the consummation of this offering. In
addition, shortly after this offering, Healtheon intends to file a registration
statement on Form S-8 covering the 13,811,659 shares of common stock reserved
for issuance under the 1996 Plan and the 1998 Purchase Plan based upon the
number of options outstanding as of November 30, 1998. Shares of common stock
registered under any registration statement will, subject to Rule 144 volume
limitations applicable to affiliates, be available for sale in the open market,
unless the shares are subject to vesting restrictions with Healtheon or the
lock-up agreements described above.
 
                                       70
<PAGE>
                     CERTAIN UNITED STATES TAX CONSEQUENCES
                      TO NON-U.S. HOLDERS OF COMMON STOCK
 
    The following is a general discussion of some of the United States federal
income and estate tax consequences relevant to holders of common stock that are
non-U.S. Holders. A non-U.S. Holder is a holder of common stock that is not, for
United States federal income tax purposes, any of the following:
 
    - a citizen or resident of the United States;
 
    - a corporation, partnership or other entity created or organized in or
      under the laws of the United States or any state thereof;
 
    - an estate, the income of which is subject to U.S. federal income taxation
      regardless of its source; or
 
    - a trust that meets the following two tests: (A) a U.S. court is able to
      exercise primary supervision over the administration of the trust, and (B)
      one or more U.S. persons have the authority to control all substantial
      decisions of the trust.
 
This discussion does not consider the specific facts and circumstances that may
be relevant to particular non-U.S. Holders in light of their personal
circumstances and does not address the treatment of those holders under the laws
of any state, local or foreign taxing jurisdiction. Further, the discussion is
based on provisions of the United States Internal Revenue Code of 1986, as
amended, or the "Code", Treasury regulations under the Code, and administrative
and judicial interpretations of the Code. This discussion is based on the
provisions of the Code as they are in effect on the date of this prospectus. All
of these provisions are subject to change or different interpretation on a
possibly retroactive basis. THIS DISCUSSION IS LIMITED TO NON-U.S. HOLDERS WHO
HOLD THE COMMON STOCK AS A CAPITAL ASSET. EACH PROSPECTIVE HOLDER IS URGED TO
CONSULT ITS TAX ADVISOR WITH RESPECT TO THE UNITED STATES FEDERAL TAX
CONSEQUENCES OF ACQUIRING, HOLDING AND DISPOSING OF COMMON STOCK, AS WELL AS ANY
TAX CONSEQUENCES THAT MAY ARISE UNDER THE LAWS OF ANY STATE, LOCAL OR FOREIGN
TAXING JURISDICTION.
 
DIVIDENDS
 
    Dividends paid to a non-U.S. Holder of common stock will be subject to
United States federal withholding tax at a 30% rate or a lower rate as may be
specified by an applicable income tax treaty. Withholding may not apply if the
dividends are effectively connected with the conduct of a trade or business
within the United States and, if an applicable income tax treaty requires as a
condition for the non-U.S. holder to be subject to United States income tax on a
net income basis for the dividends, are attributable to a United States
permanent establishment of such holder. The "effectively connected" dividends
are subject to tax at rates applicable to United States citizens, resident
aliens and domestic United States corporations, and are not generally subject to
withholding. Any effectively connected dividends received by a corporate
non-U.S. Holder may also, under certain circumstances, be subject to an
additional "branch profits tax" at a 30% rate or a lower rate as may be
specified by an applicable income tax treaty.
 
    Under currently effective United States Treasury regulations, dividends paid
prior to January 1, 2000 to an address in a foreign country are presumed to be
paid to a resident of that country, unless the payer has knowledge to the
contrary, for purposes of the withholding discussed above and, under the current
interpretation of United States Treasury regulations, for purposes of
determining the applicability of a tax treaty rate. Under recently finalized
United States Treasury regulations that will generally be effective for
distributions after December 31, 1999, or the "Final Withholding Regulations",
however, a non-U.S. Holder of common stock who wishes to claim the benefit of an
applicable treaty rate would be required to satisfy applicable certification
requirements. In addition, under the Final Withholding Regulations, in the case
of common stock held by a foreign partnership, (1) the certification requirement
would generally be applied to the partners of the partnership and (2) the
partnership would be required to provide certain information, including a United
States taxpayer identification number. The Final Withholding Regulations provide
look-through rules for tiered partnerships.
 
                                       71
<PAGE>
    A non-U.S. Holder of common stock that is eligible for a reduced rate of
United States withholding tax under a tax treaty may obtain a refund of any
excess amounts currently withheld by filing an appropriate claim for refund with
the United States Internal Revenue Service.
 
GAIN ON DISPOSITION OF COMMON STOCK
 
    A non-U.S. holder generally will not be subject to United States federal
income tax for gain recognized on a disposition of common stock unless one of
the following conditions is satisfied:
 
    - the gain is effectively connected with a trade or business conducted by
      the non-U.S. Holder in the United States and, if an applicable income tax
      treaty requires as a condition for such non-U.S. Holder to be subject to
      United States taxation on a net income basis for gain from the sale or
      other disposition of the common stock, is attributable to a permanent
      establishment maintained in the United States by such non-U.S. Holder;
 
    - in the case of a non-U.S. Holder who is an individual and holds the common
      stock as a capital asset, the holder is present in the United States for
      183 or more days in the taxable year of the sale and certain other
      conditions exist;
 
    - Healtheon is or has been a "United States real property holding
      corporation" for federal income tax purposes and, in the event that the
      common stock is considered "regularly traded on an established securities
      market," the non-U.S. Holder held, directly or indirectly at any time
      during the five-year period ending on the date of disposition, more than
      5% of the common stock and is not eligible for any treaty exemption; or
 
    - the non-U.S. Holder is subject to tax under to certain provisions of the
      Code applicable to U.S. expatriates.
 
    Effectively connected gains realized by a corporate non-U.S. Holder may
also, under certain circumstances, be subject to an additional "branch profits
tax" at a 30% rate or a lower rate as may be specified by an applicable income
tax treaty.
 
    Healtheon believes it is not currently, and does not anticipate becoming, a
"United States real property holding corporation" for federal income tax
purposes.
 
FEDERAL ESTATE TAXES
 
    Common stock held by a non-U.S. Holder at the time of death will be included
in the holder's gross estate for United States federal estate tax purposes,
unless an applicable estate tax treaty provides otherwise.
 
INFORMATION REPORTING AND BACKUP WITHHOLDING
 
    Under current law, United States information reporting requirements, other
than reporting of dividend payments for purposes of the withholding tax noted
above, and backup withholding tax generally will not apply to dividends paid to
non-U.S. Holders that are either subject to the 30% withholding discussed above
or that are not subject to withholding because an applicable tax treaty reduces
the withholding. Otherwise, backup withholding of United States federal income
tax at a rate of 31% may apply to dividends paid with respect to common stock to
holders that are not "exempt recipients" and that fail to provide certain
information including the holder's United States taxpayer identification number.
Generally, unless the payer of dividends has actual knowledge that the payee is
a United States person, the payer may treat dividend payments to a payee with a
foreign address as exempt from information reporting and backup withholding.
However, under the Final Withholding Regulations, dividend payments generally
will be subject to information reporting and backup withholding unless
applicable certification requirements are satisfied. See the discussion above
with respect to the rules applicable to foreign partnerships under the Final
Withholding Regulations.
 
                                       72
<PAGE>
    In general, United States information reporting and backup withholding
requirements also will not apply to a payment made outside the United States of
the proceeds of a sale of common stock through an office outside the United
States of a non-United States broker. However, United States information
reporting, but not backup withholding, requirements will apply to a payment made
outside the United States of the proceeds of a sale of common stock through an
office outside the United States of a broker that is a United States person,
that derives 50% or more of its gross income for certain periods from the
conduct of a trade or business in the United States, that is a "controlled
foreign corporation" as to the United States, or, in the case of payments made
after December 31, 1999, a foreign partnership with certain connections to the
United States, unless the broker has documentary evidence in its records that
the holder or beneficial owner is a non-United States person or the holder or
beneficial owner otherwise establishes an exemption. Payment of the proceeds of
the sale of common stock to or through a United States office of a broker is
currently subject to both United States backup withholding and information
reporting unless the holder certifies its non-United States status under
penalties of perjury or otherwise establishes an exemption.
 
    A non-U.S. Holder generally may obtain a refund of any excess amounts
withheld under the backup withholding rules by filing the appropriate claim for
refund with the United States Internal Revenue Service.
 
                                       73
<PAGE>
                                  UNDERWRITERS
 
    Under the terms and subject to the conditions contained in an underwriting
agreement dated the date hereof, or the "underwriting agreement," the U.S.
underwriters named below and the international underwriters named below have
severally agreed to purchase, and Healtheon has agreed to sell to them,
severally, the respective number of shares of common stock set forth opposite
the names of such underwriters below:
 
<TABLE>
<CAPTION>
                                                                                                       NUMBER OF
  NAME                                                                                                   SHARES
- -----------------------------------------------------------------------------------------------------  ----------
<S>                                                                                                    <C>
U.S. Underwriters:
  Morgan Stanley & Co. Incorporated..................................................................   1,600,000
  Goldman, Sachs & Co................................................................................   1,600,000
  Hambrecht & Quist LLC..............................................................................     520,000
  Volpe Brown Whelan & Company, LLC..................................................................     280,000
                                                                                                       ----------
    Subtotal.........................................................................................   4,000,000
                                                                                                       ----------
 
International Underwriters:
  Morgan Stanley & Co. International Limited.........................................................     400,000
  Goldman Sachs International........................................................................     400,000
  Hambrecht & Quist LLC..............................................................................     130,000
  Volpe Brown Whelan & Company, LLC..................................................................      70,000
                                                                                                       ----------
    Subtotal.........................................................................................   1,000,000
                                                                                                       ----------
      Total..........................................................................................   5,000,000
                                                                                                       ----------
                                                                                                       ----------
</TABLE>
 
    The U.S. underwriters and the international underwriters are collectively
referred to as the "underwriters." The underwriting agreement provides that the
obligations of the several underwriters to pay for and accept delivery of the
shares of common stock offered hereby are subject to the approval of certain
legal matters by their counsel and to certain other conditions. The underwriters
are obligated to take and pay for all of the shares of common stock offered by
this prospectus if any shares are taken. However, the underwriters are not
required to take the shares covered by the U.S. underwriters' over-allotment
option described below.
 
    Pursuant to the agreement between U.S. and international underwriters, each
U.S. underwriter has represented and agreed that, with certain exceptions: (1)
it is not purchasing any shares for the account of anyone other than a United
States or Canadian Person (as defined) and (2) it has not offered or sold, and
will not offer or sell, directly or indirectly, any Shares or distribute any
prospectus relating to the shares outside the United States or Canada or to
anyone other than a United States or Canadian Person. Pursuant to the agreement
between U.S. and international underwriters, each international underwriter has
represented and agreed that, with certain exceptions: (1) it is not purchasing
any shares for the account of any United States or Canadian Person and (2) it
has not offered or sold, and will not offer or sell, directly or indirectly, any
shares or distribute any prospectus relating to the shares in the United States
or Canada or to any United States or Canadian Person. With respect to any
underwriter that is a U.S. underwriter and an international underwriter, the
foregoing representations and agreements (1) made by it in its capacity as a
U.S. underwriter apply only to it in its capacity as a U.S. underwriter and (2)
made by it in its capacity as an international underwriter apply only to it in
its capacity as an international underwriter. The foregoing limitations do not
apply to stabilization transactions or to certain other transactions specified
in the agreement between U.S. and international underwriters. As used herein,
"United States or Canadian Person" means any national or resident of the United
States or Canada, or any corporation, pension, profit-sharing or other trust or
other entity organized under the laws of the United States or Canada or of any
political subdivision thereof, other than a branch located outside the United
 
                                       74
<PAGE>
States and Canada of any United States or Canadian Person, and includes any
United States or Canadian branch of a person who is otherwise not a United
States or Canadian Person.
 
    Pursuant to the agreement between U.S. and international underwriters, sales
may be made between the U.S. underwriters and international underwriters of any
number of shares as may be mutually agreed. The per share price of any shares
sold shall be the public offering price set forth on the cover page hereof, in
United States dollars, less an amount not greater than the per share amount of
the concession to dealers set forth below.
 
    Pursuant to the agreement between U.S. and international underwriters, each
U.S. underwriter has represented that it has not offered or sold, and has agreed
not to offer or sell, any shares, directly or indirectly, in any province or
territory of Canada or to, or for the benefit of, any resident of any province
or territory of Canada in contravention of the securities laws thereof and has
represented that any offer or sale of shares in Canada will be made only
pursuant to an exemption from the requirement to file a prospectus in the
province or territory of Canada in which such offer or sale is made. Each U.S.
underwriter has further agreed to send to any dealer who purchases from it any
of the shares a notice stating in substance that, by purchasing such shares,
such dealer represents and agrees that it has not offered or sold, and will not
offer or sell, directly or indirectly, any of such shares in any province or
territory of Canada or to, or for the benefit of, any resident of any province
or territory of Canada in contravention of the securities laws thereof and that
any offer or sale of shares in Canada will be made only pursuant to an exemption
from the requirement to file a prospectus in the province or territory of Canada
in which such offer or sale is made, and that such dealer will deliver to any
other dealer to whom it sells any of such shares a notice containing
substantially the same statement as is contained in this sentence.
 
    Pursuant to the agreement between U.S. and international underwriters, each
international underwriter has represented and agreed that (1) it has not offered
or sold and, prior to the date six months after the closing date for the sale of
the shares to the international underwriters, will not offer or sell any shares
to persons in the United Kingdom except to persons whose ordinary activities
involve them in acquiring, holding, managing or disposing of investments, as
principal or agent, for the purposes of their businesses or otherwise in
circumstances which have not resulted and will not result in an offer to the
public in the United Kingdom within the meaning of the Public Offers of
Securities Regulations 1995; (2) it has complied and will comply with all
applicable provisions of the Financial Services Act 1986 with respect to
anything done by it in relation to the shares in, from or otherwise involving
the United Kingdom; and (3) it has only issued or passed on and will only issue
or pass on in the United Kingdom any document received by it in connection with
the offering of the shares to a person who is of a kind described in Article
11(3) of the Financial Services Act 1986 (Investment Advertisements)
(Exemptions) Order 1996 or is a person to whom such document may otherwise
lawfully be issued or passed on.
 
    Pursuant to the agreement between U.S. and international underwriters, each
international underwriter has further represented that it has not offered or
sold, and has agreed not to offer or sell, directly or indirectly, in Japan or
to or for the account of any resident thereof, any of the shares acquired in
connection with the distribution contemplated in this offering, except for
offers or sales to Japanese international underwriters or dealers and except
pursuant to any exemption from the registration requirements of the Securities
and Exchange Law and otherwise in compliance with applicable provisions of
Japanese law. Each international underwriter has further agreed to send to any
dealer who purchases from it any of the shares a notice stating in substance
that, by purchasing such shares, such dealer represents and agrees that it has
not offered or sold, and will not offer or sell, any of such shares, directly or
indirectly, in Japan or to or for the account of any resident thereof except for
offers or sales to Japanese international underwriters or dealers and except
pursuant to an exemption from the registration requirements of the Securities
and Exchange Law and otherwise in compliance with applicable provisions of
Japanese law, and that such dealer will send to any other dealer to whom it
sells any of such shares a notice containing substantially the same statement as
is contained in this sentence.
 
                                       75
<PAGE>
    The underwriters initially propose to offer part of the shares of common
stock directly to the public at the public offering price set forth on the cover
page hereof and part to certain dealers at a price that represents a concession
not in excess of $.34 a share under the public offering price. Any underwriter
may allow, and such dealers may reallow, a concession not in excess of $.10 a
share to other underwriters or to certain other dealers. After the initial
offering of the shares of common stock, the offering price and other selling
terms may from time to time be varied by the underwriters.
 
    Healtheon has granted to the U.S. underwriters an option, exercisable for 30
days from the date of this prospectus, to purchase up to an aggregate of 750,000
additional shares of common stock at the public offering price set forth on the
cover page hereof, less underwriting discounts and commissions. The U.S.
underwriters may exercise such option solely for the purpose of covering
over-allotments, if any, made in connection with the offering of the shares of
common stock offered hereby. To the extent such option is exercised, each U.S.
underwriter will become obligated, subject to certain conditions, to purchase
approximately the same percentage of such additional shares of common stock as
the number set forth next to such U.S. underwriter's name in the preceding table
bears to the total number of shares of common stock set forth next to the names
of all U.S. underwriters in the preceding table.
 
    The underwriters have informed Healtheon that they do not intend sales to
discretionary accounts to exceed five percent of the total number of shares of
common stock offered by them.
 
    Healtheon has requested that the U.S. underwriters reserve up to 400,000
shares of common stock to be offered at the public offering price to employees,
friends and families of employees, service providers, employees of customers and
others. In addition, Healtheon has requested that the U.S. underwriters reserve
437,500 shares of common stock to be offered at the public offering price to
Thomas A. Jermoluk, a director of Healtheon, and certain associates of James H.
Clark, also a director of Healtheon. These people will agree to hold their
shares for at least 180 days after the date of this prospectus. This directed
share program will be administered by Morgan Stanley & Co. Incorporated. The
number of shares of common stock available for sale to the general public will
be reduced to the extent such individuals purchase such reserved shares. Any
reserved shares which are not so purchased will be offered by the underwriters
to the general public on the same basis as the other shares offered hereby.
 
    Each of Healtheon and the directors, officers and certain other stockholders
of Healtheon has agreed that, without the prior written consent of Morgan
Stanley & Co. Incorporated on behalf of the underwriters, it will not, during
the period ending 180 days after the date of this prospectus, (1) offer, pledge,
sell, contract to sell, sell any option or contract to purchase, purchase any
option or contract to sell, grant any option, right or warrant to purchase, lend
or otherwise transfer or dispose of, directly or indirectly, any shares of
common stock or any securities convertible into or exercisable or exchangeable
for common stock or (2) enter into any swap or other arrangement that transfers
to another, in whole or in part, any of the economic consequences of ownership
of the common stock, whether any such transaction described in clause (1) or (2)
above is to be settled by delivery of common stock or such other securities, in
cash or otherwise. The restrictions described in this paragraph do not apply to
(x) the sale of shares to the underwriters, (y) the issuance by Healtheon of
shares of common stock upon the exercise of an option or a warrant or the
conversion of a security outstanding on the date of this prospectus of which the
underwriters have been advised in writing, or (z) transactions by any person
other than Healtheon relating to shares of common stock or other securities
acquired in open market transactions after the completion of the offering of the
shares, provided that purchasers in transactions described in clause (y) enter
into similar "lock-up" agreements.
 
    In November 1998, Morgan Stanley Equity Funding, Inc. purchased 833,334
shares of Series A Preferred Stock at a purchase price of $6.00 per share and
The Goldman Sachs Group, L.P. purchased 166,667 shares of Series A Preferred
Stock at a purchase price of $6.00 per share. These entities have agreed for a
period of 90 days from the date of this prospectus not to sell, transfer,
assign, pledge or
 
                                       76
<PAGE>
hypothecate these shares, or the common stock issuable when this preferred stock
converts into common stock on the closing of this offering.
 
    In order to facilitate the offering of the common stock, the underwriters
may engage in transactions that stabilize, maintain or otherwise affect the
price of the common stock. Specifically, the underwriters may over-allot in
connection with the offering, creating a short position in the common stock for
their own account. In addition, to cover over-allotments or to stabilize the
price of the common stock, the underwriters may bid for, and purchase, shares of
common stock in the open market. Finally, the underwriting syndicate may reclaim
selling concessions allowed to an underwriter or a dealer for distributing the
common stock in the offering if the syndicate repurchases previously distributed
common stock in transactions to cover syndicate short positions, in
stabilization transactions or otherwise. Any of these activities may stabilize
or maintain the market price of the common stock above independent market
levels. The underwriters are not required to engage in these activities, and may
end any of these activities at any time.
 
    Healtheon and the underwriters have agreed to indemnify each other against
certain liabilities, including liabilities under the Securities Act.
 
    Certain of the underwriters from time to time perform various investment
banking services for Healtheon, for which such underwriters receive customary
compensation.
 
PRICING OF THE OFFERING
 
    Prior to this offering, there has been no public market for the common
stock. The initial public offering price was determined by negotiations between
Healtheon and the U.S. underwriters. Among the factors considered in determining
the initial public offering price were the future prospects of Healtheon and its
industry in general, sales, earnings and certain other financial and operating
information of Healtheon in recent periods, and the price-earnings ratios,
price-sales ratios, market prices of securities and certain financial and
operating information of companies engaged in activities similar to those of
Healtheon.
 
                                 LEGAL MATTERS
 
    The validity of the issuance of the shares of common stock offered hereby
will be passed upon for Healtheon by Wilson Sonsini Goodrich & Rosati,
Professional Corporation, Palo Alto, California. Certain legal matters in
connection with this offering will be passed upon for the underwriters by
Fenwick & West LLP, Palo Alto, California.
 
                                    EXPERTS
 
    Healtheon was incorporated in December 1995 and did not commence operations
until January 1996. Thus, the financial statements of ActaMed for the year ended
December 31, 1995 also represent the financial statements of Healtheon on a
pooled basis for that period.
 
    The consolidated financial statements of Healtheon Corporation at December
31, 1996 and 1997, and for the two years in the period ended December 31, 1997
appearing in this prospectus and Registration Statement have been audited by
Ernst & Young LLP, independent auditors, as set forth in their report thereon
appearing elsewhere herein which, as to the year ended December 31, 1996, is
based in part on the report of Deloitte & Touche LLP, independent auditors. The
consolidated financial statements referred to above are included in reliance
upon such report given upon the authority of such firm as experts in accounting
and auditing.
 
    The consolidated financial statements of ActaMed Corporation for the year
ended December 31, 1995, included in this Prospectus and Registration Statement
have been audited by Deloitte & Touche LLP, independent auditors, as stated in
their report appearing herein. The consolidated financial statements of
 
                                       77
<PAGE>
ActaMed Corporation as of December 31, 1996 and for the year then ended, which
are not separately presented in this Prospectus and Registration Statement, have
been audited by Deloitte & Touche LLP, independent auditors, as stated in their
report appearing herein. Such financial statements are included in reliance upon
the report of such firm given upon their authority as experts in accounting and
auditing.
 
    The statements of divisional net loss and UnitedHealth Group's net
investment and of divisional cash flows of EDI Services Group, a division of
UnitedHealth Group, included in this prospectus and Registration Statement have
been audited by Deloitte and Touche LLP, independent auditors, as stated in
their report appearing herein, and are included in reliance upon the report of
such firm given upon their authority as experts in accounting and auditing.
 
                      WHERE YOU CAN FIND MORE INFORMATION
 
    Healtheon has filed with the Securities and Exchange Commission, or the
"Commission," a registration statement on Form S-1 under the Securities Act, and
the rules and regulations promulgated thereunder, with respect to the common
stock offered hereby. This prospectus, which constitutes a part of the
registration statement, does not contain all of the information set forth in the
registration statement and the exhibits thereto. Statements contained in this
prospectus as to the contents of any contract or other document that is filed as
an exhibit to the registration statement are not necessarily complete and each
such statement is qualified in all respects by reference to the full text of
such contract or document. For further information with respect to Healtheon and
the common stock, reference is hereby made to the registration statement and the
exhibits thereto, which may be inspected and copied at the principal office of
the Commission, 450 Fifth Street, N.W., Washington, D.C. 20549, and at the
regional offices of the Commission located at Seven World Trade Center, Suite
1300, New York, New York 10048 and Citicorp Center, 500 West Madison Street,
Suite 1400, Chicago, Illinois 60661, and copies of all or any part thereof may
be obtained at prescribed rates from the Commission's Public Reference Section
at such addresses. Also, the Commission maintains a World Wide Web site on the
Internet at http://www.sec.gov that contains reports, proxy and information
statements and other information regarding registrants that file electronically
with the Commission.
 
    Upon completion of this offering, Healtheon will become subject to the
information and periodic reporting requirements of the Exchange Act and, in
accordance therewith, will file periodic reports, proxy and information
statements and other information with the Commission. Such periodic reports,
proxy and information statements and other information will be available for
inspection and copying at the regional offices, public reference facilities and
Web site of the Commission referred to above.
 
                                       78
<PAGE>
                   INDEX TO CONSOLIDATED FINANCIAL STATEMENTS
 
<TABLE>
<CAPTION>
<S>                                                                         <C>
CONSOLIDATED FINANCIAL STATEMENTS OF HEALTHEON CORPORATION:
 
Report of Ernst & Young LLP, Independent Auditors.........................   F-2
 
Report of Deloitte & Touche LLP, Independent Auditors.....................   F-3
 
Consolidated Balance Sheets...............................................   F-4
 
Consolidated Statements of Operations.....................................   F-5
 
Consolidated Statement of Convertible Redeemable Preferred Stock and
  Stockholders' Equity (Net Capital Deficiency)...........................   F-6
 
Consolidated Statements of Cash Flows.....................................   F-9
 
Notes to Consolidated Financial Statements................................  F-11
 
FINANCIAL STATEMENTS OF EDI SERVICES, INC.:
 
Report of Deloitte and Touche LLP, Independent Auditors...................  F-34
 
Statement of Divisional Net Loss and United's Net Investment..............  F-35
 
Statement of Divisional Cash Flows........................................  F-36
 
Notes to Financial Statements.............................................  F-37
</TABLE>
 
                                      F-1
<PAGE>
               REPORT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS
 
The Board of Directors and Stockholders
 
Healtheon Corporation
 
    We have audited the accompanying consolidated balance sheets of Healtheon
Corporation as of December 31, 1996 and 1997, and the related consolidated
statements of operations, convertible redeemable preferred stock and
stockholders' equity (net capital deficiency), and cash flows for each of the
two years in the period ended December 31, 1997. These financial statements are
the responsibility of the Company's management. Our responsibility is to express
an opinion on these financial statements based on our audits. In May 1998, the
Company acquired ActaMed Corporation in a transaction that was accounted for as
a pooling of interests. We did not audit the financial statements of ActaMed
Corporation for the year ended December 31, 1996, which statements reflect total
assets constituting approximately 82% of the related consolidated financial
statement totals at December 31, 1996 and revenues and a net loss constituting
approximately 89% and 54%, respectively, of the related consolidated financial
statement totals for the year ended December 31, 1996. Those statements were
audited by other auditors whose report has been furnished to us, and our
opinion, insofar as it relates to data included for ActaMed Corporation, is
based solely on the report of the other auditors.
 
    We conducted our audits in accordance with generally accepted accounting
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits and the report of the other auditors provide a
reasonable basis for our opinion.
 
    In our opinion, based on our audits and the report of the other auditors,
the financial statements referred to above present fairly, in all material
respects, the consolidated financial position of Healtheon Corporation at
December 31, 1996 and 1997, and the consolidated results of its operations and
its cash flows for each of the two years in the period ended December 31, 1997,
in conformity with generally accepted accounting principles.
 
                                          /s/ ERNST & YOUNG LLP
 
Palo Alto, California
February 27, 1998,
except for Notes 1 and 2, as to which the date is September 26, 1998
 
                                      F-2
<PAGE>
INDEPENDENT AUDITORS' REPORT
 
Board of Directors of ActaMed Corporation
 
    We have audited the consolidated balance sheet of ActaMed Corporation and
subsidiary (the "Company") as of December 31, 1996 and the related consolidated
statements of operations, convertible redeemable preferred stock and
stockholders' equity (net capital deficiency), and cash flows for each of the
two years in the period ended December 31, 1996 (the consolidated financial
statements for 1996 are not separately presented herein). These financial
statements are the responsibility of the Company's management. Our
responsibility is to express an opinion on these consolidated financial
statements based on our audits.
 
    We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.
 
    In our opinion, such consolidated financial statements present fairly, in
all material respects, the financial position of the Company as of December 31,
1996 and the results of its operations and its cash flows for each of the two
years in the period ended December 31, 1996 in conformity with generally
accepted accounting principles.
 
/s/ DELOITTE & TOUCHE LLP
 
Atlanta, Georgia
June 20, 1997 (September 26, 1998 as to Note 1--Net Loss per Common Share,
paragraph 2 and Note 2--Acquisition of EDI Services, Inc., paragraph 4)
 
                                      F-3
<PAGE>
                             HEALTHEON CORPORATION
 
                          CONSOLIDATED BALANCE SHEETS
 
                (IN THOUSANDS, EXCEPT SHARE AND PER SHARE DATA)
 
<TABLE>
<CAPTION>
                                                                                  DECEMBER 31,
                                                                             ----------------------
                                                                                1996        1997
                                                                             ----------  ----------  SEPTEMBER 30,
                                                                                                         1998
                                                                                                     -------------
                                                                                                      (UNAUDITED)
<S>                                                                          <C>         <C>         <C>
                                                      ASSETS
Current assets:
  Cash and cash equivalents................................................  $    7,539  $   16,504   $     4,526
  Short-term investments...................................................          --       5,300           866
  Accounts receivable, net of allowance for doubtful accounts of $41, $71
   and $130 in 1996, 1997 and 1998, respectively...........................         959       2,723         5,104
  Due from related parties.................................................       1,742       1,533         1,159
  Other current assets.....................................................         437         527           621
                                                                             ----------  ----------  -------------
  Total current assets.....................................................      10,677      26,587        12,276
Property and equipment, net................................................       4,534       5,500        11,276
Intangible assets, net.....................................................      16,555      18,768        23,742
Other assets...............................................................       2,641       2,892         2,977
                                                                             ----------  ----------  -------------
                                                                             $   34,407  $   53,747   $    50,271
                                                                             ----------  ----------  -------------
                                                                             ----------  ----------  -------------
 
                          LIABILITIES AND STOCKHOLDERS' EQUITY (NET CAPITAL DEFICIENCY)
Current liabilities:
  Borrowings under line of credit..........................................  $       30  $    3,425   $     1,415
  Accounts payable.........................................................       1,359       2,225         4,472
  Accrued compensation.....................................................         242         448         2,465
  Other accrued liabilities................................................       1,097       1,265         3,871
  Current portion of capital lease obligations.............................         763       1,038         1,716
  Deferred revenue.........................................................       4,681       3,396         4,392
                                                                             ----------  ----------  -------------
  Total current liabilities................................................       8,172      11,797        18,331
Capital lease obligations, net of current portion..........................       1,210         932         1,714
Commitments
Convertible redeemable preferred stock, $.016 par value, issuable in
  series: 16,488,860 shares authorized in 1996 and 1997, none in 1998;
  14,170,947, 16,488,860 and no shares issued and outstanding in 1996, 1997
  and 1998, respectively; at amounts paid in...............................      39,578      50,948            --
Stockholders' equity (net capital deficiency):
  Convertible preferred stock, $.0001 par value, issuable in series:
   48,020,000 shares authorized in 1996 and 1997, none in 1998; 13,285,000,
   21,002,692 and no shares issued and outstanding in 1996, 1997 and 1998,
   respectively; at amounts paid in........................................      11,607      43,756            --
  Common stock, $.0001 par value, 75,000,000 shares authorized; 8,652,422,
   9,436,724 and 54,422,868 shares issued and outstanding in 1996, 1997 and
   1998, respectively......................................................           1           1             5
  Additional paid-in capital...............................................       1,523       4,502       119,645
  Note receivable from officer.............................................          --        (349)           --
  Deferred stock compensation..............................................          --      (2,151)       (4,184)
  Accumulated deficit......................................................     (27,684)    (55,689)      (85,240)
                                                                             ----------  ----------  -------------
  Total stockholders' equity (net capital deficiency)......................     (14,553)     (9,930)       30,226
                                                                             ----------  ----------  -------------
                                                                             $   34,407  $   53,747   $    50,271
                                                                             ----------  ----------  -------------
                                                                             ----------  ----------  -------------
</TABLE>
 
                            SEE ACCOMPANYING NOTES.
 
                                      F-4
<PAGE>
                    CONSOLIDATED STATEMENTS OF OPERATIONS(1)
 
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
 
<TABLE>
<CAPTION>
                                                                                  HEALTHEON CORPORATION
                                                          ACTAMED     ----------------------------------------------
                                                        CORPORATION
                                                        ------------       YEARS ENDED          NINE MONTHS ENDED
                                                         YEAR ENDED        DECEMBER 31,           SEPTEMBER 30,
                                                        DECEMBER 31,  ----------------------  ----------------------
                                                            1995         1996        1997        1997        1998
                                                        ------------  ----------  ----------  ----------  ----------
                                                                                                   (UNAUDITED)
<S>                                                     <C>           <C>         <C>         <C>         <C>
Revenue:
  Services............................................   $      458   $    1,795  $    4,301  $    1,216  $   18,326
  Services to related parties(2)......................           --        4,237       7,309       5,199      14,320
  Software licenses...................................        1,717        4,981       1,780         585         585
                                                        ------------  ----------  ----------  ----------  ----------
  Total revenue.......................................        2,175       11,013      13,390       7,000      33,231
Operating costs and expenses:
  Cost of revenue:
    Cost of services..................................        1,573        1,648       4,011       1,080      18,688
    Cost of services to related parties...............           --        4,919       6,536       4,648      13,206
    Cost of software licenses.........................          343          160          --          --          --
                                                        ------------  ----------  ----------  ----------  ----------
    Total cost of revenue.............................        1,916        6,727      10,547       5,728      31,894
  Development and engineering.........................        2,446        8,596      12,986       9,681      13,036
  Sales, general and administrative...................        1,749        9,042      11,031       7,477      17,041
  Amortization of intangible assets...................           --        3,189       4,249       3,187       6,703
                                                        ------------  ----------  ----------  ----------  ----------
  Total operating costs and expenses..................        6,111       27,554      38,813      26,073      68,674
                                                        ------------  ----------  ----------  ----------  ----------
Loss from operations..................................       (3,936)     (16,541)    (25,423)    (19,073)    (35,443)
Interest income.......................................          208          539         611         359         834
Interest expense......................................           (6)         (56)       (323)       (177)       (361)
Dividends on ActaMed's convertible redeemable
  preferred stock.....................................           --       (2,548)     (2,870)     (2,382)       (890)
                                                        ------------  ----------  ----------  ----------  ----------
Net loss..............................................       (3,734)     (18,606)    (28,005)    (21,273)    (35,860)
Dividends on ActaMed's convertible redeemable
  preferred stock.....................................         (724)          --          --          --          --
                                                        ------------  ----------  ----------  ----------  ----------
Net loss applicable to common stockholders............   $   (4,458)  $  (18,606) $  (28,005) $  (21,273) $  (35,860)
                                                        ------------  ----------  ----------  ----------  ----------
                                                        ------------  ----------  ----------  ----------  ----------
Basic and diluted net loss per common share...........   $     (.85)  $    (2.83) $    (3.88) $    (3.03) $    (1.24)
                                                        ------------  ----------  ----------  ----------  ----------
                                                        ------------  ----------  ----------  ----------  ----------
Weighted-average shares outstanding used in computing
  basic and diluted net loss per common share.........        5,246        6,583       7,223       7,019      28,934
                                                        ------------  ----------  ----------  ----------  ----------
                                                        ------------  ----------  ----------  ----------  ----------
Pro forma basic and diluted net loss per common share
  (unaudited).........................................                            $     (.56)             $     (.74)
                                                                                  ----------              ----------
                                                                                  ----------              ----------
Shares used in computing pro forma basic and diluted
  net loss per common share (unaudited)...............                                44,715                  47,263
                                                                                  ----------              ----------
                                                                                  ----------              ----------
</TABLE>
 
- ---------
 
(1) Because Healtheon did not commence operations until January 1996, the
    ActaMed statement of operations presented for the year ended December 31,
    1995 represents the statement of operations of Healtheon for that period on
    a pooled basis.
 
(2) Revenue from services to related parties consists of revenue from
    UnitedHealth Group and SmithKline Labs, customers that are also significant
    stockholders of the Company.
 
                            SEE ACCOMPANYING NOTES.
 
                                      F-5
<PAGE>
        CONSOLIDATED STATEMENT OF CONVERTIBLE REDEEMABLE PREFERRED STOCK
              AND STOCKHOLDERS' EQUITY (NET CAPITAL DEFICIENCY)(1)
 
                       (IN THOUSANDS, EXCEPT SHARE DATA)
 
                              ACTAMED CORPORATION
<TABLE>
<CAPTION>
                                          CONVERTIBLE
                                     REDEEMABLE PREFERRED   CONVERTIBLE PREFERRED
                                             STOCK                  STOCK             COMMON STOCK
                                     ---------------------  ---------------------  -------------------
                                       SHARES      AMOUNT     SHARES      AMOUNT     SHARES    AMOUNT
                                     -----------  --------  -----------  --------  ----------  -------
<S>                                  <C>          <C>       <C>          <C>       <C>         <C>
BALANCES AT DECEMBER 31, 1994......    8,800,880  $  8,343           --  $     --   8,250,000  $   200
Net loss...........................           --        --           --        --          --       --
Issuance of common stock pursuant
  to option exercises by
  employees........................           --        --           --        --   1,071,250       21
Issuance of Series B convertible
  redeemable preferred stock for
  cash (less issuance costs of
  $36).............................    3,448,276     6,963           --        --          --       --
Dividends accrued on convertible
  redeemable preferred stock.......           --       724           --        --          --       --
                                     -----------  --------  -----------  --------  ----------  -------
BALANCES AT DECEMBER 31, 1995......   12,249,156  $ 16,030           --  $     --   9,321,250  $   221
                                     -----------  --------  -----------  --------  ----------  -------
                                     -----------  --------  -----------  --------  ----------  -------
 
                                        HEALTHEON CORPORATION
 
BALANCES AT DECEMBER 31, 1995
  (REFLECTING THE EXCHANGE RATIO OF
  .6272)...........................    7,682,671  $ 16,030           --  $     --   5,846,288  $     1
Net loss...........................           --        --           --        --          --       --
Issuance of common stock to
  founders and employees for
  cash.............................           --        --           --        --   2,806,134       --
Issuance of Series A convertible
  preferred stock for cash (less
  issuance costs of $27)...........           --        --   10,285,000     5,115          --       --
Issuance of Series B convertible
  preferred stock for cash (less
  issuance costs of $8)............           --        --    3,000,000     5,992          --       --
Issuance of Series B convertible
  preferred stock warrant to
  investor for services............           --        --           --       500          --       --
Issuance of Series C convertible
  redeemable preferred stock for
  acquisition......................    6,488,276    21,000           --        --          --       --
Issuance of common stock
  warrants.........................           --        --           --        --          --       --
Dividends accrued on convertible
  redeemable preferred stock.......           --     2,548           --        --          --       --
                                     -----------  --------  -----------  --------  ----------  -------
BALANCES AT DECEMBER 31, 1996......   14,170,947    39,578   13,285,000    11,607   8,652,422        1
 
<CAPTION>
                                                                                                TOTAL
                                                     NOTE                                   STOCKHOLDERS'
                                     ADDITIONAL   RECEIVABLE     DEFERRED                    EQUITY (NET
                                      PAID-IN        FROM         STOCK       ACCUMULATED      CAPITAL
                                      CAPITAL      OFFICER     COMPENSATION     DEFICIT      DEFICIENCY)
                                     ----------   ----------   ------------   -----------   -------------
<S>                                  <C>          <C>          <C>            <C>           <C>
BALANCES AT DECEMBER 31, 1994......   $   1,883     $  --        $    --       $ (5,344)      $ (3,261)
Net loss...........................          --        --             --         (3,734)        (3,734)
Issuance of common stock pursuant
  to option exercises by
  employees........................          --        --             --             --             21
Issuance of Series B convertible
  redeemable preferred stock for
  cash (less issuance costs of
  $36).............................          --        --             --             --             --
Dividends accrued on convertible
  redeemable preferred stock.......        (724)       --             --             --           (724)
                                     ----------   ----------   ------------   -----------   -------------
BALANCES AT DECEMBER 31, 1995......   $   1,159     $  --        $    --       $ (9,078)      $ (7,698)
                                     ----------   ----------   ------------   -----------   -------------
                                     ----------   ----------   ------------   -----------   -------------
 
BALANCES AT DECEMBER 31, 1995
  (REFLECTING THE EXCHANGE RATIO OF
  .6272)...........................   $   1,379     $  --        $    --       $ (9,078)      $ (7,698)
Net loss...........................          --        --             --        (18,606)       (18,606)
Issuance of common stock to
  founders and employees for
  cash.............................         140        --             --             --            140
Issuance of Series A convertible
  preferred stock for cash (less
  issuance costs of $27)...........          --        --             --             --          5,115
Issuance of Series B convertible
  preferred stock for cash (less
  issuance costs of $8)............          --        --             --             --          5,992
Issuance of Series B convertible
  preferred stock warrant to
  investor for services............          --        --             --             --            500
Issuance of Series C convertible
  redeemable preferred stock for
  acquisition......................          --        --             --             --             --
Issuance of common stock
  warrants.........................           4        --             --             --              4
Dividends accrued on convertible
  redeemable preferred stock.......          --        --             --             --             --
                                     ----------   ----------   ------------   -----------   -------------
BALANCES AT DECEMBER 31, 1996......       1,523        --             --        (27,684)       (14,553)
</TABLE>
 
- -------------
 
(1) Because Healtheon did not commence operations until January 1996, the
    ActaMed statement of convertible redeemable preferred stock and
    stockholders' equity (net capital deficiency) presented for the year ended
    December 31, 1995 represents the statement of stockholders' equity of
    Healtheon for that period on a pooled basis.
 
                            SEE ACCOMPANYING NOTES.
 
                                      F-6
<PAGE>
        CONSOLIDATED STATEMENT OF CONVERTIBLE REDEEMABLE PREFERRED STOCK
        AND STOCKHOLDERS' EQUITY (NET CAPITAL DEFICIENCY)(1) (CONTINUED)
 
                       (IN THOUSANDS, EXCEPT SHARE DATA)
 
                             HEALTHEON CORPORATION
<TABLE>
<CAPTION>
                                          CONVERTIBLE
                                     REDEEMABLE PREFERRED   CONVERTIBLE PREFERRED
                                             STOCK                  STOCK             COMMON STOCK
                                     ---------------------  ---------------------  -------------------
                                       SHARES      AMOUNT     SHARES      AMOUNT     SHARES    AMOUNT
                                     -----------  --------  -----------  --------  ----------  -------
<S>                                  <C>          <C>       <C>          <C>       <C>         <C>
BALANCES AT DECEMBER 31, 1996......   14,170,947  $ 39,578   13,285,000  $ 11,607   8,652,422  $     1
Net loss...........................           --        --           --        --          --       --
Issuance of common stock pursuant
  to option and restricted stock
  exercises by employees...........           --        --           --        --   1,397,844       --
Repurchase of employee common
  stock............................           --        --           --        --    (613,542)      --
Issuance of Series A and Series B
  convertible preferred stock for
  services.........................           --        --       45,000        55          --       --
Issuance of Series B convertible
  preferred stock for cash.........           --        --       15,000        30          --       --
Issuance of Series B convertible
  preferred stock to officer for
  note receivable..................           --        --      250,000       500          --       --
Issuance of Series B convertible
  preferred stock warrants in
  connection with bridge
  financing........................           --        --           --        64          --       --
Issuance of Series C convertible
  preferred stock for cash and
  conversion of bridge note........           --        --    2,600,000     6,500          --       --
Issuance of Series D convertible
  preferred stock for cash.........           --        --    4,807,692    25,000          --       --
Issuance of Series D convertible
  redeemable preferred stock for
  asset purchase...................    2,317,913     8,500           --        --          --       --
Repayment of note receivable from
  officer..........................           --        --           --        --          --       --
Dividends accrued on convertible
  redeemable preferred stock.......           --     2,870           --        --          --       --
Deferred stock compensation........           --        --           --        --          --       --
Amortization of deferred stock
  compensation.....................           --        --           --        --          --       --
                                     -----------  --------  -----------  --------  ----------  -------
BALANCES AT DECEMBER 31, 1997......   16,488,860    50,948   21,002,692    43,756   9,436,724        1
 
<CAPTION>
                                                                                                TOTAL
                                                     NOTE                                   STOCKHOLDERS'
                                     ADDITIONAL   RECEIVABLE     DEFERRED                    EQUITY (NET
                                      PAID-IN        FROM         STOCK       ACCUMULATED      CAPITAL
                                      CAPITAL      OFFICER     COMPENSATION     DEFICIT      DEFICIENCY)
                                     ----------   ----------   ------------   -----------   -------------
<S>                                  <C>          <C>          <C>            <C>           <C>
BALANCES AT DECEMBER 31, 1996......   $   1,523     $  --        $    --       $(27,684)      $(14,553)
Net loss...........................          --        --             --        (28,005)       (28,005)
Issuance of common stock pursuant
  to option and restricted stock
  exercises by employees...........         297        --             --             --            297
Repurchase of employee common
  stock............................         (31)       --             --             --            (31)
Issuance of Series A and Series B
  convertible preferred stock for
  services.........................          --        --             --             --             55
Issuance of Series B convertible
  preferred stock for cash.........          --        --             --             --             30
Issuance of Series B convertible
  preferred stock to officer for
  note receivable..................          --      (500)            --             --             --
Issuance of Series B convertible
  preferred stock warrants in
  connection with bridge
  financing........................          --        --             --             --             64
Issuance of Series C convertible
  preferred stock for cash and
  conversion of bridge note........          --        --             --             --          6,500
Issuance of Series D convertible
  preferred stock for cash.........          --        --             --             --         25,000
Issuance of Series D convertible
  redeemable preferred stock for
  asset purchase...................          --        --             --             --             --
Repayment of note receivable from
  officer..........................          --       151             --             --            151
Dividends accrued on convertible
  redeemable preferred stock.......          --        --             --             --             --
Deferred stock compensation........       2,713        --         (2,713)            --             --
Amortization of deferred stock
  compensation.....................          --        --            562             --            562
                                     ----------   ----------   ------------   -----------   -------------
BALANCES AT DECEMBER 31, 1997......       4,502      (349)        (2,151)       (55,689)        (9,930)
</TABLE>
 
- -------------
 
(1) Because Healtheon did not commence operations until January 1996, the
    ActaMed statement of convertible redeemable preferred stock and
    stockholders' equity (net capital deficiency) presented for the year ended
    December 31, 1995 represents the statement of stockholders' equity of
    Healtheon for that period on a pooled basis.
 
                            SEE ACCOMPANYING NOTES.
 
                                      F-7
<PAGE>
        CONSOLIDATED STATEMENT OF CONVERTIBLE REDEEMABLE PREFERRED STOCK
        AND STOCKHOLDERS' EQUITY (NET CAPITAL DEFICIENCY)(1) (CONTINUED)
 
                       (IN THOUSANDS, EXCEPT SHARE DATA)
 
                             HEALTHEON CORPORATION
<TABLE>
<CAPTION>
                                          CONVERTIBLE
                                     REDEEMABLE PREFERRED   CONVERTIBLE PREFERRED
                                             STOCK                  STOCK             COMMON STOCK
                                     ---------------------  ---------------------  -------------------
                                       SHARES      AMOUNT     SHARES      AMOUNT     SHARES    AMOUNT
                                     -----------  --------  -----------  --------  ----------  -------
<S>                                  <C>          <C>       <C>          <C>       <C>         <C>
BALANCES AT DECEMBER 31, 1997......   16,488,860  $ 50,948   21,002,692  $ 43,756   9,436,724  $     1
Net loss (unaudited)...............           --        --           --        --          --       --
Issuance of common stock pursuant
  to option exercises by employees
  (unaudited)......................           --        --           --        --   2,247,606       --
Issuance of Series B convertible
  preferred stock pursuant to
  warrant exercises (unaudited)....           --        --    1,017,229     2,034          --       --
Issuance of Series D convertible
  redeemable preferred stock for
  asset purchase (unaudited).......      763,548     2,800           --        --          --       --
Dividends accrued on convertible
  redeemable preferred stock
  (unaudited)......................           --       890           --        --          --       --
Conversion of redeemable preferred
  and preferred stock to common
  stock (unaudited)................  (17,252,408)  (54,638) (22,019,921)  (45,790) 39,272,329        4
Issuance of common stock for asset
  purchase (unaudited).............           --        --           --        --   2,936,209       --
Repayment of note receivable from
  officer (unaudited)..............           --        --           --        --          --       --
Deferred stock compensation
  (unaudited)......................           --        --           --        --          --       --
Amortization of deferred stock
  compensation (unaudited).........           --        --           --        --          --       --
Issuance of common stock pursuant
  to restricted stock purchase by
  employees (unaudited)............           --        --           --        --     530,000       --
                                     -----------  --------  -----------  --------  ----------  -------
BALANCES, SEPTEMBER 30, 1998
  (UNAUDITED)......................           --  $     --           --  $     --  54,422,868  $     5
                                     -----------  --------  -----------  --------  ----------  -------
                                     -----------  --------  -----------  --------  ----------  -------
 
<CAPTION>
                                                                                                TOTAL
                                                     NOTE                                   STOCKHOLDERS'
                                     ADDITIONAL   RECEIVABLE     DEFERRED                    EQUITY (NET
                                      PAID-IN        FROM         STOCK       ACCUMULATED      CAPITAL
                                      CAPITAL      OFFICER     COMPENSATION     DEFICIT      DEFICIENCY)
                                     ----------   ----------   ------------   -----------   -------------
<S>                                  <C>          <C>          <C>            <C>           <C>
BALANCES AT DECEMBER 31, 1997......   $   4,502     $(349)       $(2,151)      $(55,689)      $ (9,930)
Net loss (unaudited)...............          --        --             --        (35,860)       (35,860)
Issuance of common stock pursuant
  to option exercises by employees
  (unaudited)......................       1,260        --             --             --          1,260
Issuance of Series B convertible
  preferred stock pursuant to
  warrant exercises (unaudited)....          --        --             --             --          2,034
Issuance of Series D convertible
  redeemable preferred stock for
  asset purchase (unaudited).......          --        --             --             --             --
Dividends accrued on convertible
  redeemable preferred stock
  (unaudited)......................          --        --             --             --             --
Conversion of redeemable preferred
  and preferred stock to common
  stock (unaudited)................      94,115        --             --          6,309         54,638
Issuance of common stock for asset
  purchase (unaudited).............      13,220        --             --             --         13,220
Repayment of note receivable from
  officer (unaudited)..............          --       349             --             --            349
Deferred stock compensation
  (unaudited)......................       4,083        --         (4,083)            --             --
Amortization of deferred stock
  compensation (unaudited).........          --        --          2,050             --          2,050
Issuance of common stock pursuant
  to restricted stock purchase by
  employees (unaudited)............       2,465        --             --             --          2,465
                                     ----------   ----------   ------------   -----------   -------------
BALANCES, SEPTEMBER 30, 1998
  (UNAUDITED)......................   $ 119,645     $  --        $(4,184)      $(85,240)      $ 30,226
                                     ----------   ----------   ------------   -----------   -------------
                                     ----------   ----------   ------------   -----------   -------------
</TABLE>
 
- -------------
 
(1) Because Healtheon did not commence operations until January 1996, the
    ActaMed statement of convertible redeemable preferred stock and
    stockholders' equity (net capital deficiency) presented for the year ended
    December 31, 1995 represents the statement of stockholders' equity of
    Healtheon for that period on a pooled basis.
 
                            SEE ACCOMPANYING NOTES.
 
                                      F-8
<PAGE>
                    CONSOLIDATED STATEMENTS OF CASH FLOWS(1)
 
                                 (IN THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                                      HEALTHEON CORPORATION
                                                                ACTAMED     ------------------------------------------
                                                              CORPORATION                          NINE MONTHS ENDED
                                                             -------------  YEARS ENDED DECEMBER
                                                              YEAR ENDED            31,              SEPTEMBER 30,
                                                             DECEMBER 31,   --------------------  --------------------
                                                                1995(1)       1996       1997       1997       1998
                                                             -------------  ---------  ---------  ---------  ---------
                                                                                                      (UNAUDITED)
<S>                                                          <C>            <C>        <C>        <C>        <C>
Cash flows from operating activities:
Net loss...................................................    $  (3,734)   $ (18,606) $ (28,005) $ (21,273) $ (35,860)
Adjustments to reconcile net loss to net cash used in
  operating activities:
  Depreciation and amortization............................          359        6,366      9,319      6,937     13,488
  Amortization of deferred stock compensation..............           --           --        562        309      2,050
  Warrants and preferred stock issued for services.........           --          500        119         55         --
  Dividends on ActaMed's convertible redeemable preferred
   stock...................................................           --        2,548      2,870      2,382        890
  Changes in operating assets and liabilities:
    Accounts receivable....................................          (36)      (5,066)      (806)       651     (1,819)
    Other assets...........................................          (77)        (325)      (224)       122       (162)
    Accounts payable.......................................           49        1,139        751       (263)     2,580
    Accrued compensation and other liabilities.............          516          800        345        681      3,964
    Deferred revenue.......................................        1,603        3,078     (1,285)      (285)       996
                                                             -------------  ---------  ---------  ---------  ---------
Net cash used in operating activities......................       (1,320)      (9,566)   (16,354)   (10,684)   (13,873)
                                                             -------------  ---------  ---------  ---------  ---------
 
Cash flows from investing activities:
Purchase of short-term investments.........................           --           --     (5,300)        --     (4,341)
Maturities of short-term investments.......................           --           --         --         --      8,775
Increase in restricted cash................................           --           --       (867)        --         --
Purchases of property and equipment........................         (464)      (2,027)    (2,817)      (449)    (5,071)
Cash paid in business combination..........................           --           --         --         --       (652)
Acquisition costs related to business combination..........           --         (316)        --         --         --
Capitalized internally developed software costs............           --       (1,001)      (291)      (291)        --
                                                             -------------  ---------  ---------  ---------  ---------
Net cash used in investing activities......................         (464)      (3,344)    (9,275)      (740)    (1,289)
                                                             -------------  ---------  ---------  ---------  ---------
 
Cash flows from financing activities:
Proceeds from line of credit borrowings and bridge notes...           --           30      5,395      2,000         --
Payment of line of credit borrowings.......................           --           --         --         --     (2,010)
Proceeds from line of credit borrowings from related
  party....................................................           --           --         --         --      1,000
Payments of line of credit borrowings from related party...           --           --         --         --     (1,000)
Proceeds from issuance of preferred stock..................        6,963       11,107     29,530      4,470      2,034
Proceeds from issuance of common stock, net of
  repurchases..............................................           21          144        266         18      3,725
Payments on note receivable from officer...................           --           --        151         --        349
Principal payments of capital lease obligations............           --         (218)      (748)      (573)      (914)
                                                             -------------  ---------  ---------  ---------  ---------
Net cash from financing activities.........................        6,984       11,063     34,594      5,915      3,184
                                                             -------------  ---------  ---------  ---------  ---------
Net increase (decrease) in cash and cash equivalents.......        5,200       (1,847)     8,965     (5,509)   (11,978)
Cash and cash equivalents at beginning of period...........        4,186        9,386      7,539      7,539     16,504
                                                             -------------  ---------  ---------  ---------  ---------
Cash and cash equivalents at end of period.................    $   9,386    $   7,539  $  16,504  $   2,030  $   4,526
                                                             -------------  ---------  ---------  ---------  ---------
                                                             -------------  ---------  ---------  ---------  ---------
</TABLE>
 
- ------------
 
(1) Because Healtheon did not commence operations until January 1996, the
    statement of cash flows presented for the year ended December 31, 1995
    represents the statement of cash flows of Healtheon for that period on a
    pooled basis.
 
                                      F-9
<PAGE>
              CONSOLIDATED STATEMENTS OF CASH FLOWS(1) (CONTINUED)
 
                                 (IN THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                                      HEALTHEON CORPORATION
                                                                ACTAMED     ------------------------------------------
                                                              CORPORATION                          NINE MONTHS ENDED
                                                             -------------  YEARS ENDED DECEMBER
                                                              YEAR ENDED            31,              SEPTEMBER 30,
                                                             DECEMBER 31,   --------------------  --------------------
                                                                1995(1)       1996       1997       1997       1998
                                                             -------------  ---------  ---------  ---------  ---------
                                                                                                      (UNAUDITED)
<S>                                                          <C>            <C>        <C>        <C>        <C>
Supplemental disclosure of cash flow information:
Interest paid..............................................    $       5    $      56  $     252  $     154  $     379
                                                             -------------  ---------  ---------  ---------  ---------
                                                             -------------  ---------  ---------  ---------  ---------
 
Supplemental schedule of noncash investing and financing
  activities:
Equipment acquired under capital lease obligations.........    $      --    $   2,083  $     774  $     472  $   2,278
                                                             -------------  ---------  ---------  ---------  ---------
                                                             -------------  ---------  ---------  ---------  ---------
Issuance of note receivable from officer for preferred
  stock....................................................    $      --    $      --  $     500  $      --  $      --
                                                             -------------  ---------  ---------  ---------  ---------
                                                             -------------  ---------  ---------  ---------  ---------
Conversion of bridge notes to preferred stock..............    $      --    $      --  $   2,000  $   2,000  $      --
                                                             -------------  ---------  ---------  ---------  ---------
                                                             -------------  ---------  ---------  ---------  ---------
Dividends on ActaMed's convertible redeemable preferred
  stock....................................................    $     724    $      --  $      --  $      --  $      --
                                                             -------------  ---------  ---------  ---------  ---------
                                                             -------------  ---------  ---------  ---------  ---------
Issuance of convertible redeemable preferred stock for
  business combination.....................................    $      --    $  21,000  $      --  $      --  $      --
                                                             -------------  ---------  ---------  ---------  ---------
                                                             -------------  ---------  ---------  ---------  ---------
Issuance of convertible redeemable preferred stock for
  asset purchase...........................................    $      --    $      --  $   8,500  $      --  $   2,800
                                                             -------------  ---------  ---------  ---------  ---------
                                                             -------------  ---------  ---------  ---------  ---------
Issuance of common stock for asset purchase................    $      --    $      --  $      --  $      --  $   4,900
                                                             -------------  ---------  ---------  ---------  ---------
                                                             -------------  ---------  ---------  ---------  ---------
Issuance of common stock for business combination..........    $      --    $      --  $      --  $      --  $   8,320
                                                             -------------  ---------  ---------  ---------  ---------
                                                             -------------  ---------  ---------  ---------  ---------
Deferred stock compensation related to options granted.....    $      --    $      --  $   2,713  $   1,101  $   4,083
                                                             -------------  ---------  ---------  ---------  ---------
                                                             -------------  ---------  ---------  ---------  ---------
Conversion of convertible redeemable preferred and
  convertible preferred stock to common stock..............    $      --    $      --  $      --  $      --  $  94,119
                                                             -------------  ---------  ---------  ---------  ---------
                                                             -------------  ---------  ---------  ---------  ---------
</TABLE>
 
- ------------
 
(1) Because Healtheon did not commence operations until January 1996, the
    statement of cash flows presented for the year ended December 31, 1995
    represents the statement of cash flows of Healtheon for that period on a
    pooled basis.
 
                             SEE ACCOMPANYING NOTES
 
                                      F-10
<PAGE>
                             HEALTHEON CORPORATION
 
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
 
    BASIS OF PRESENTATION
 
    In May 1998, Healtheon Corporation acquired ActaMed Corporation in a merger
transaction accounted for as a pooling of interests (see Note 2). ActaMed was
incorporated in 1992. Healtheon was incorporated on December 26, 1995 and was
considered to be in the development stage through late 1997. All financial
information has been restated to reflect the combined operations of Healtheon
and ActaMed. All 1995 financial statement information represents that of
ActaMed. Because Healtheon did not commence operations until January 1996, the
financial statements of ActaMed for the year ended December 31, 1995 also
represent the financial statements of Healtheon on a pooled basis for that
period.
 
    NATURE OF OPERATIONS
 
    Healtheon is pioneering the use of the Internet to simplify workflows,
decrease costs and improve the quality of patient care throughout the healthcare
industry. We have designed and developed an Internet-based information and
transaction platform, which we call the Healtheon Platform, that allows us to
create Virtual Healthcare Networks, or VHNs, that facilitate and streamline
interactions among the myriad participants in the healthcare industry. Our VHN
solution includes a suite of services delivered through applications operating
on our Internet-based platform. Our solution enables the secure exchange of
information among disparate healthcare information systems and supports a broad
range of healthcare transactions, including enrollment, eligibility
determination, referrals and authorization, laboratory and diagnostic test
ordering, clinical data retrieval and claims processing. We provide our own
applications on the Healtheon Platform and also enable third-party applications
to operate on the platform. In addition to VHNs, Healtheon provides consulting,
implementation and network management services to enable our customers to take
advantage of the capabilities of the Healtheon Platform.
 
    Healtheon has incurred operating losses to date and had an accumulated
deficit of $85,240,000 at September 30, 1998. Our activities have been primarily
financed through private placements of equity securities. We had cash, cash
equivalents and short-term investments totaling $5,392,000 at September 30,
1998. As noted above and as further discussed in Note 2, Healtheon merged with
ActaMed in May 1998. This merger may significantly affect our operating cash
needs. We may need to raise additional capital through the issuance of debt or
equity securities. There can be no assurance that we will be able to raise
additional financing, or that such financing will be available on terms
satisfactory to us, if at all.
 
    INTERIM FINANCIAL INFORMATION
 
    The financial information as of September 30, 1998 and for the nine months
ended September 30, 1997 and 1998 is unaudited but includes all adjustments,
consisting only of normal recurring adjustments, that Healtheon's management
considers necessary for a fair presentation of Healtheon's operating results and
cash flows for such period. Results for the nine months ended September 30, 1998
are not necessarily indicative of results to be expected for the full fiscal
year of 1998 or for any future period.
 
    PRINCIPLES OF CONSOLIDATION
 
    The consolidated financial statements include the accounts of Healtheon and
its wholly owned subsidiaries. All significant inter-company balances and
transactions have been eliminated.
 
                                      F-11
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
    ACCOUNTING ESTIMATES
 
    The preparation of financial statements in conformity with generally
accepted accounting principles requires management to make estimates and
assumptions that affect the amounts reported in the financial statements. Actual
results could differ materially from these estimates.
 
    CASH, CASH EQUIVALENTS AND SHORT-TERM INVESTMENTS
 
    All highly liquid investments with an original maturity from date of
purchase of three months or less are considered to be cash equivalents.
Healtheon's cash, cash equivalents and short-term investments are invested in
various investment-grade commercial paper, money market accounts and
certificates of deposit. All of our short-term investments mature within nine
months. The fair value of our cash equivalents and short-term investments is as
follows (in thousands):
 
<TABLE>
<CAPTION>
                                                                DECEMBER 31,
                                                            --------------------  SEPTEMBER 30,
                                                              1996       1997         1998
                                                            ---------  ---------  -------------
                                                                                  (UNAUDITED)
<S>                                                         <C>        <C>        <C>
Cash equivalents:
  Corporate and other non-government debt securities......  $      --  $  12,704    $   2,808
  Money market funds......................................      5,603      3,429        1,372
                                                            ---------  ---------       ------
                                                                5,603     16,133        4,180
Short-term investments:
  Corporate and other non-government debt securities......         --      5,300          866
                                                            ---------  ---------       ------
                                                            $   5,603  $  21,433    $   5,046
                                                            ---------  ---------       ------
                                                            ---------  ---------       ------
</TABLE>
 
    Net unrealized gains (losses) were immaterial at December 31, 1996 and 1997
and September 30, 1998.
 
    Management determines the appropriate classification of debt and equity
securities at the time of purchase and reevaluates such designation as of each
balance sheet date. Marketable debt and equity securities are classified as
available-for-sale, and are carried at their fair value, with the unrealized
gains and losses, when material, reported net-of-tax in a separate component of
stockholders' equity. Realized gains and losses and declines in value judged to
be other-than-temporary on available-for-sale securities are included in
interest income. The cost of securities sold is based on specific
identification. Interest and dividends on securities classified as
available-for-sale are included in interest income.
 
    Additionally, at December 31, 1997 and September 30, 1998, we had restricted
cash of $867,000, related to a letter of credit invested in a certificate of
deposit at a financial institution as a security deposit for its office
facilities (see Note 6). This amount is included in other assets in the
accompanying consolidated balance sheets.
 
                                      F-12
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
    PROPERTY AND EQUIPMENT
 
    Property and equipment are stated at cost, net of accumulated amortization
and depreciation. Depreciation is computed using the straight-line method over
the estimated useful life of the related asset, generally three to seven years.
Leasehold improvements and equipment acquired under capital leases are amortized
over the shorter of the lease term or the estimated useful life of the related
asset.
 
    INTANGIBLE ASSETS
 
    Intangible assets related to software technology rights, services agreements
and goodwill are amortized on a straight-line basis over three years. Intangible
assets related to assembled workforce are amortized on a straight-line basis
over two years.
 
    SOFTWARE DEVELOPMENT COSTS
 
    Software development costs are incurred in the development or enhancement of
software utilized in providing Healtheon's business management systems and
services. Software development costs incurred after the establishment of
technological feasibility for each product or process are capitalized and
capitalization ceases when the product or process is available for general
release to customers or is put into service. Capitalized internally developed
software costs were approximately $1,001,000, $291,000 and $288,000 for the
years ended December 31, 1996 and 1997 and the nine months ended September 30,
1997. There were no internally developed software costs capitalized for the year
ended December 31, 1995 or for the nine months ended September 30, 1998.
Capitalized internally developed software costs are amortized based on the
greater of the amount determined using the straight line method over the
estimated useful economic life of the software or the ratio of remaining
unamortized costs to current and expected future revenue from the software.
Amortization expense related to our capitalized internally developed software
costs included in cost of revenue was approximately $134,000 and $376,000 for
the years ended December 31, 1996 and 1997. Amortization expense was
approximately $268,000 and $782,000 for the nine months ended September 30, 1997
and 1998. There was no amortization expense related to ActaMed's capitalized
internally developed software costs for the year ended December 31, 1995.
 
    LONG-LIVED ASSETS
 
    Healtheon continually monitors events and changes in circumstances that
could indicate carrying amounts of long-lived assets, including intangible
assets, may not be recoverable. When such events or changes in circumstances are
present, we assess the recoverability of long-lived assets by determining
whether the carrying value of such assets will be recovered through undiscounted
expected future cash flows. In June 1998, we evaluated the carrying value of the
capitalized internally developed software in light of the changes in operations
resulting from the acquisition of ActaMed by Healtheon. We determined that we
expected no future cash flows to be generated by this software and, accordingly,
wrote off the remaining unamortized balance of $603,000 related to capitalized
internally developed software. This amount is included in the $782,000
amortization expense for the nine months ended September 30, 1998 noted above.
No impairment losses were recorded for the years ended December 31, 1995, 1996
and 1997 or for the nine months ended September 30, 1997.
 
                                      F-13
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
    REVENUE RECOGNITION
 
    Healtheon earns revenue from services and services to related parties, both
of which include providing access to our network-based services and performing
development and consulting services, and from licensing software. We earn
network-based services revenue from fixed fee subscription arrangements, which
is recognized ratably over the term of the applicable agreement, and from
arrangements that are priced on a per-transaction or per-user basis, which is
recognized as the services are performed. Revenue from development projects is
recognized on a percentage-of-completion basis or as such services are
performed, depending on the terms of the contract. Revenue from consulting
services is recognized as such services are performed. Cash received in excess
of revenue recognized relating to such services has been recorded as deferred
revenue in the accompanying consolidated balance sheets. Revenue from services
to related parties consists of services revenue attributable to UnitedHealth
Group and SmithKline Labs. To date, we have derived no significant revenue from
brokers, value-added resellers or systems integrators.
 
    During the year ended December 31, 1997, we entered into agreements with two
customers to manage and operate their current and expanding information
technology, or IT, operations, to develop a suite of specific Internet-based
commercial software applications and to assist these customers in migrating from
their current IT operating environment to these new applications. We utilize our
own personnel, certain outside contractors and certain personnel and facilities
of the customers that are leased under contract terms to us for these services.
The cost of these leased customer personnel and facilities is included as part
of the total costs of the IT and development services that we billed to the
customers. For the year ended December 31, 1997 and the nine months ended
September 30, 1998, we recognized revenue of approximately $2,100,000 and
$10,915,000 for the IT services and approximately $200,000 and $4,772,000 for
the development services. Revenue recognized for IT services for the year ended
December 31, 1997 and the nine months ended September 30, 1998 included amounts
related to leased personnel and facilities, in total, of $1,909,000 and
$8,806,000. These amounts were also included in cost of revenue for the
respective periods.
 
    We recognize revenue from license fees when a noncancellable license
agreement has been signed with a customer, the software product covered by the
license agreement has been delivered, there are no uncertainties surrounding
product acceptance, there are no significant future performance obligations, the
license fees are fixed and determinable and collection of the license fees is
considered probable. Our products do not require significant customization.
 
    In October 1997, the American Institute of Certified Public Accountants
issued Statement of Position (SOP) 97-2, "Software Revenue Recognition." SOP
97-2 was effective January 1, 1998 and generally requires revenue earned on
software arrangements involving multiple elements such as software products,
upgrades, enhancements, post-contract customer support, installation and
training to be allocated to each element based on the relative fair values of
the elements. There was no material change to our accounting for revenue as a
result of the adoption of SOP 97-2.
 
    ActaMed entered into a national marketing and licensing agreement, or the
Agreement, with International Business Machines Corporation in 1995 that granted
IBM a nonexclusive, nontransferable right to market ActaMed's software and
services for a total of $6,300,000. For the years ended December 31, 1995, 1996
and 1997, approximately $1,700,000, $3,400,000 and $1,200,000 of this amount
 
                                      F-14
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
was recognized as software license revenue upon delivery of the software. No
software license revenue was recognized under this agreement for the nine months
ended September 30, 1997 or 1998.
 
    In December 1996, we entered into a new agreement, or the License, to
license our newly granted patent to IBM. As part of the License, IBM agreed to
pay ActaMed $4,800,000 over a four-year period. Additionally, in conjunction
with the License, we issued IBM a five-year warrant to purchase 282,522 shares
of our common stock at a price of $7.97 per share. Because of the extended
payment terms and our contentious relationship with IBM, we concluded that the
license fee was not assured of collection and, accordingly, we are recognizing
this revenue as the proceeds are collected. For the years ended December 31,
1996 and 1997, we recognized revenue from the License of $995,000 and $780,000.
For the nine months ended September 30, 1997 and 1998, we recognized revenue
from the License of $585,000 and $585,000. At December 31, 1997, amounts due
from IBM of $738,000 and $1,715,000 were included in accounts receivable and
other assets. At September 30, 1998, amounts due from IBM of $795,000 and
$1,112,000 were included in accounts receivable and other assets. Deferred
revenue at December 31, 1996 and 1997 and September 30, 1998 included
$3,121,000, $2,341,000 and $1,756,000 related to the License.
 
    FAIR VALUE OF FINANCIAL INSTRUMENTS
 
    The fair value for marketable debt securities is based on quoted market
prices. The carrying value of these securities approximates their fair value.
 
    The fair value of notes is estimated by discounting the future cash flows
using the current interest rates at which similar loans would be made to
borrowers with similar credit ratings and for the same remaining maturities. The
carrying value of the note receivable from an officer approximated its fair
value.
 
    The fair value of short-term and long-term capital lease obligations is
estimated based on current interest rates available to Healtheon for debt
instruments with similar terms, degrees of risk and remaining maturities. The
carrying values of these obligations approximate their respective fair values.
 
    CONCENTRATION OF CREDIT RISK AND SIGNIFICANT CUSTOMERS
 
    Healtheon currently derives a substantial portion of its consolidated
revenue from a few large customers, two of which are related parties. Two
customers represented 35% and 17% of the total balance of trade accounts
receivable and amounts due from related parties at December 31, 1997, and three
customers represented 20%, 18% and 15% of the total balance of trade accounts
receivable and amounts due from related parties at September 30, 1998. We
believe that the concentration of credit risk in our trade receivables, with
respect to our limited customer base, is substantially mitigated by our credit
evaluation process. We do not require collateral. To date, our bad debt
write-offs have not been significant. During the years ended December 31, 1996
and 1997 and the nine months ended September 30, 1998 we added approximately
$41,000, $35,000 and $66,000 to our bad debt reserves. Total write-offs of
uncollectible amounts were zero, $5,000 and $7,000 in these periods.
 
    For the year ended December 31, 1995, one customer accounted for 85% of
consolidated revenue. For the year ended December 31, 1996, two customers
accounted for 46% and 38% of consolidated revenue. For the year ended December
31, 1997, two customers accounted for 55% and 15% of consolidated
 
                                      F-15
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
revenue. For the nine months ended September 30, 1998, four customers accounted
for 27%, 22%, 21% and 20% of consolidated revenue.
 
    We operate solely within one business segment, the development and marketing
of healthcare transaction and information services delivered over the Internet,
private intranets or other networks. Through September 30, 1998, we had no
export sales.
 
    ACCOUNTING FOR STOCK-BASED COMPENSATION
 
    Healtheon grants stock options for a fixed number of shares to employees
with an exercise price equal to the fair market value of the shares at the date
of grant. As permitted under Statement of Financial Accounting Standards (SFAS)
No. 123, "Accounting for Stock-Based Compensation," we account for stock option
grants to employees and directors in accordance with APB Opinion No. 25,
"Accounting for Stock Issued to Employees."
 
    NET LOSS PER COMMON SHARE
 
    Basic net loss per common share and diluted net loss per common share are
presented in conformity with SFAS No. 128, "Earnings Per Share," for all periods
presented. In accordance with the Securities and Exchange Commission Staff
Accounting Bulletin No. 98, common stock and convertible preferred stock issued
or granted for nominal consideration prior to the anticipated effective date of
our initial public offering must be included in the calculation of basic and
diluted net loss per common share as if they had been outstanding for all
periods presented. To date, we have not had any issuances or grants for nominal
consideration.
 
    In accordance with SFAS No. 128, basic net loss per common share has been
computed using the weighted-average number of shares of common stock outstanding
during the period, less shares subject to repurchase. For the year ended
December 31, 1995, the weighted-average number of shares of ActaMed reflects the
effect of the exchange ratio of 0.6272. Basic pro forma net loss per common
share, as presented in the statements of operations, has been computed as
described above and also gives effect, under Securities and Exchange Commission
guidance, to the conversion of the convertible and convertible redeemable
preferred stock (using the if-converted method) from the original date of
issuance. On May 19, 1998, in connection with Healtheon's acquisition of
ActaMed, all outstanding shares of Healtheon's convertible preferred stock and
ActaMed's convertible redeemable preferred stock were converted into an
aggregate of 39,272,329 shares of common stock. There were no shares of
convertible or convertible redeemable preferred stock outstanding at September
30, 1998.
 
                                      F-16
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
 
    The following table presents the calculation of basic and diluted and pro
forma basic and diluted net loss per common share follows (in thousands, except
per share data):
 
<TABLE>
<CAPTION>
                                                                    YEARS ENDED                  NINE MONTHS
                                                                   DECEMBER 31,              ENDED SEPTEMBER 30,
                                                         ---------------------------------  ----------------------
                                                           1995        1996        1997        1997        1998
                                                         ---------  ----------  ----------  ----------  ----------
                                                                                                 (UNAUDITED)
<S>                                                      <C>        <C>         <C>         <C>         <C>
Net loss applicable to common stockholders.............  $  (4,458) $  (18,606) $  (28,005) $  (21,273) $  (35,860)
                                                         ---------  ----------  ----------  ----------  ----------
                                                         ---------  ----------  ----------  ----------  ----------
Basic and diluted:
  Weighted-average shares of common stock
    outstanding........................................      5,246       7,398       8,621       8,396      30,389
  Less: Weighted-average shares subject to
    repurchase.........................................     --            (815)     (1,398)     (1,377)     (1,455)
                                                         ---------  ----------  ----------  ----------  ----------
Weighted-average shares used in computing basic and
  diluted net loss per common share....................      5,246       6,583       7,223       7,019      28,934
                                                         ---------  ----------  ----------  ----------  ----------
                                                         ---------  ----------  ----------  ----------  ----------
Basic and diluted net loss per common share............  $    (.85) $    (2.83) $    (3.88) $    (3.03) $    (1.24)
                                                         ---------  ----------  ----------  ----------  ----------
                                                         ---------  ----------  ----------  ----------  ----------
Pro forma:
Net loss applicable to common stockholders.............                         $  (28,005)             $  (35,860)
Add: Dividends on ActaMed convertible redeemable
  preferred stock......................................                              2,870                     890
                                                                                ----------              ----------
Pro forma net loss.....................................                         $  (25,135)             $  (34,970)
                                                                                ----------              ----------
                                                                                ----------              ----------
Shares used above......................................                              7,223                  28,934
Pro forma adjustment to reflect weighted effect of
  assumed conversion of convertible preferred stock....                             37,492                  18,329
                                                                                ----------              ----------
Shares used in computing pro forma basic and diluted
  net loss per common share (unaudited)................                             44,715                  47,263
                                                                                ----------              ----------
                                                                                ----------              ----------
Pro forma basic and diluted net loss per common share
  (unaudited)..........................................                         $     (.56)             $     (.74)
                                                                                ----------              ----------
                                                                                ----------              ----------
</TABLE>
 
    We have excluded all convertible redeemable preferred stock, convertible
preferred stock, warrants, outstanding stock options and shares subject to
repurchase by Healtheon from the calculation of diluted loss per common share
because all such securities are anti-dilutive for all periods presented. For the
years ended December 31, 1995, 1996 and 1997, the total number of shares
excluded from the calculation of diluted loss per share were 10,157,109,
36,643,084 and 51,216,689. For the nine months ended September 30, 1997 and 1998
the total number of shares excluded from the calculation of diluted loss per
share were 46,893,485 and 12,687,723. See Notes 9, 10 and 11 for further
information on these securities.
 
                                      F-17
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
    COMPREHENSIVE LOSS
 
    Healtheon has no material components of other comprehensive loss and
accordingly the comprehensive loss is the same as net loss for all periods
presented.
 
    RECENT ACCOUNTING PRONOUNCEMENTS
 
    In June 1997, the Financial Accounting Standards Board (FASB) issued SFAS
No. 131, "Disclosures about Segments of an Enterprise and Related Information."
Healtheon is required to adopt SFAS No. 131 for the year ending December 31,
1998. SFAS No. 131 requires disclosure of certain information regarding
operating segments, products and services, geographic areas of operation and
major customers. Adoption of SFAS No. 131 is expected to have no material impact
on our financial condition or results of operations.
 
    In June 1998, the FASB issued SFAS No. 133, "Accounting for Derivative
Instruments and Hedging Activities." We are required to adopt SFAS No. 133 for
the year ending December 31, 2000. SFAS No. 133 establishes methods of
accounting for derivative financial instruments and hedging activities related
to those instruments as well as other hedging activities. Because we currently
hold no derivative financial instruments and does not currently engage in
hedging activities, adoption of SFAS No. 133 is expected to have no material
impact on our financial condition or results of operations.
 
    In March 1998, the American Institute of Certified Public Accountants issued
SOP 98-1, "Accounting for the Costs of Computer Software Developed or Obtained
for Internal Use." SOP 98-1 requires that entities capitalize certain costs
related to internal use software once certain criteria have been met. We are
required to implement SOP 98-1 for the year ending December 31, 1999. Adoption
of SOP 98-1 is expected to have no material impact on our financial condition or
results of operations.
 
2. BUSINESS COMBINATIONS
 
    ACQUISITION OF EDI SERVICES, INC.
 
    Effective March 31, 1996, ActaMed acquired EDI Services Inc. or EDI, a
wholly-owned subsidiary of UnitedHealth Group, in a transaction through which
EDI became a wholly-owned subsidiary of ActaMed. ActaMed issued 6,488,276 shares
of Series C convertible redeemable preferred stock with a fair value of
$21,000,000 and incurred acquisition-related costs of approximately $316,000 in
connection with the acquisition. EDI is a provider of electronic data
interchange services to health care providers and has marketed its health care
network product, ProviderLink, to providers of UnitedHealth Group's local health
plans since 1992.
 
    In connection with the acquisition, UnitedHealth Group and ActaMed entered
into a five-year Services and License Agreement under which we earn transaction
fee revenue by providing certain health care information services to
UnitedHealth Group and its provider network and ProviderLink subscribers.
 
    The acquisition was accounted for as a purchase. Accordingly, the operations
of EDI were included in our consolidated statements of operations only after
March 31, 1996. Assets and liabilities acquired in connection with this
acquisition were recorded at their estimated fair market values. Approximately
$359,000 of the purchase price was allocated to certain equipment and the
remaining approximately
 
                                      F-18
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
2. BUSINESS COMBINATIONS (CONTINUED)
$20,957,000 of the purchase price was allocated to intangible assets, consisting
principally of software technology rights, the Services and License Agreement,
trademarks and goodwill.
 
    Subsequent to the issuance of the financial statements for 1996 and 1997,
ActaMed changed the allocation of the purchase price associated with the
acquisition of the EDI technology to decrease the amount previously expensed as
in process research and development costs and increase the amount capitalized as
software technology rights. The financial statements for ActaMed for the year
ended December 31, 1996, have been reissued to reflect this restatement.
 
    Intangible assets arising from the acquisition of EDI at March 31, 1996 are
summarized as follows (in thousands):
 
<TABLE>
<CAPTION>
                                                                     AMORTIZATION
                                                                        PERIOD
                                                                    ---------------
<S>                                                                 <C>              <C>
Goodwill..........................................................      3 years      $   8,012
Software technology rights........................................      3 years          8,333
Service and License Agreement.....................................      3 years          2,855
Trademarks........................................................      3 years            216
Other intangibles.................................................      3 years          1,541
                                                                                     ---------
                                                                                     $  20,957
                                                                                     ---------
                                                                                     ---------
</TABLE>
 
    The following pro forma information gives effect to the acquisition of EDI
as if such transaction had occurred as of the beginning of each respective year
(in thousands, except per share data):
 
<TABLE>
<CAPTION>
                                                                             DECEMBER 31,
                                                                        ----------------------
                                                                           1995        1996
                                                                        ----------  ----------
                                                                             (UNAUDITED)
<S>                                                                     <C>         <C>
Net revenue...........................................................  $    6,330  $   12,031
                                                                        ----------  ----------
                                                                        ----------  ----------
Net loss applicable to common stockholders............................  $  (11,475) $  (20,492)
                                                                        ----------  ----------
                                                                        ----------  ----------
Basic and diluted net loss per common share...........................  $    (2.19) $    (3.11)
                                                                        ----------  ----------
                                                                        ----------  ----------
</TABLE>
 
    ACQUISITION OF ACTAMED CORPORATION
 
    On May 19, 1998, Healtheon completed its acquisition of ActaMed, a Georgia
corporation that develops and markets an integrated health care network, in a
transaction that has been accounted for as a pooling of interests. Accordingly,
the financial information presented reflects the combined financial position and
operations of Healtheon and ActaMed for all dates and periods presented.
Healtheon issued 23,271,355 shares of its common stock in exchange for all of
the outstanding shares of common and convertible redeemable preferred stock of
ActaMed. Healtheon also assumed all outstanding stock options and warrants to
acquire 3,383,011 shares of ActaMed capital stock, after giving effect to the
exchange ratio.
 
                                      F-19
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
2. BUSINESS COMBINATIONS (CONTINUED)
    Separate results of the combined entities for the years ended December 31,
1995, 1996 and 1997 and the four months ended April 30, 1998 (period ended
immediately prior to the acquisition) were as follows (in thousands, unaudited):
 
<TABLE>
<CAPTION>
                                                                                                      FOUR MONTHS
                                                                       YEARS ENDED DECEMBER 31,          ENDED
                                                                   ---------------------------------   APRIL 30,
                                                                     1995        1996        1997         1998
                                                                   ---------  ----------  ----------  ------------
<S>                                                                <C>        <C>         <C>         <C>
Revenue:
  Healtheon......................................................  $  --      $    1,200  $    3,199   $    6,405
  ActaMed........................................................      2,175       9,813      10,191        6,690
                                                                   ---------  ----------  ----------  ------------
                                                                   $   2,175  $   11,013  $   13,390   $   13,095
                                                                   ---------  ----------  ----------  ------------
                                                                   ---------  ----------  ----------  ------------
Net loss:
  Healtheon......................................................  $  --      $   (8,543) $  (13,979)  $   (6,664)
  ActaMed........................................................     (3,734)    (10,063)    (14,026)      (6,186)
                                                                   ---------  ----------  ----------  ------------
                                                                   $  (3,734) $  (18,606) $  (28,005)  $  (12,850)
                                                                   ---------  ----------  ----------  ------------
                                                                   ---------  ----------  ----------  ------------
</TABLE>
 
    There were no significant intercompany transactions between the two
companies or significant conforming accounting adjustments.
 
    ACQUISITION OF METIS, LLC
 
    On August 25, 1998, Healtheon acquired Metis, LLC, a provider of
Internet/intranet strategic consulting, design and development of Internet-based
applications and content for the healthcare industry enabling clinical
integration and managed care process improvement. The acquisition has been
accounted for using the purchase method of accounting and, accordingly, the
purchase price has been allocated to the tangible and intangible assets acquired
and the liabilities assumed on the basis of their respective fair values on the
acquisition date. Metis' results of operations have been included in the
consolidated financial statements from its date of acquisition.
 
    Healtheon issued 1,600,000 shares of its common stock with a fair market
value of $8,320,000. Of these shares, 476,548 shares will be issued to employees
under restricted stock purchase agreements subject to a lapsing right of
repurchase, at Healtheon's option, over the respective vesting periods. In
addition, we made a cash payment of $652,000, assumed liabilities of
approximately $300,000 and incurred other acquisition related expenses,
consisting primarily of legal and other professional fees, of approximately
$100,000. The total purchase price was approximately $9,400,000. Approximately
$300,000 of the purchase price was allocated to accounts receivable and certain
assets; approximately $1,400,000 of the purchase price was allocated to the
assembled workforce of Metis and will be amortized over two years; and the
remaining $7,700,000 of the purchase price was allocated to goodwill and will be
amortized over three years.
 
                                      F-20
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
3. SERVICES AGREEMENT WITH SMITHKLINE BEECHAM CLINICAL LABORATORIES, INC.
 
    Effective December 31, 1997, Healtheon entered into a series of agreements
with SmithKline Beecham Clinical Laboratories, Inc., or SmithKline, to outsource
the network connection between their customers and SmithKline laboratories. In
connection with this transaction, SmithKline and Healtheon entered into a
five-year Services Agreement under which we will earn transaction fee revenue by
providing certain health care information services to SmithKline and its
provider customers.
 
    As part of that transaction, we acquired a license to SBCL SCAN software and
computer workstations that reside in various medical providers' offices. At
December 31, 1997, the SCAN license and the assets from one region of the
country were transferred to Healtheon for $2,000,000 in cash and 2,317,913
shares of Series D convertible redeemable preferred stock valued at $8,500,000.
In March and June 1998, the assets for the remaining regions of the country were
transferred to Healtheon and we paid the remaining purchase price of $7,700,000
through the issuance of 763,548 shares of our Series D convertible redeemable
preferred stock in March and 1,336,209 shares of our common stock in June. The
value of the services agreement and the SCAN software license totaled
$14,774,000, and the value of the computer workstations totaled $3,426,000.
 
    SmithKline determined there was substantial benefit to their existing
customers and potential marketing advantages in attracting new customers, if the
SCAN software was upgraded to a new technology platform. Accordingly, in 1998
SmithKline entered into a development agreement with Healtheon to upgrade the
technology. Payments to Healtheon are based upon achieving certain milestones in
the development effort. At September 30, 1998 we had not achieved any
milestones. Accordingly, no development revenue had been recognized under this
development agreement.
 
4. PROPERTY AND EQUIPMENT
 
    Property and equipment consisted of the following (in thousands):
 
<TABLE>
<CAPTION>
                                                                 DECEMBER 31,
                                                             --------------------
                                                               1996       1997
                                                             ---------  ---------  SEPTEMBER 30,
                                                                                       1998
                                                                                   -------------
                                                                                    (UNAUDITED)
<S>                                                          <C>        <C>        <C>
Computer equipment.........................................  $   3,677  $   6,238    $  12,458
Office equipment, furniture and fixtures...................      1,185      1,237        2,885
Purchased software for internal use........................      1,001      1,240        1,852
Leasehold improvements.....................................        303        328        1,604
                                                             ---------  ---------  -------------
                                                                 6,166      9,043       18,799
Less accumulated depreciation and amortization.............     (1,632)    (3,543)      (7,523)
                                                             ---------  ---------  -------------
Property and equipment, net................................  $   4,534  $   5,500    $  11,276
                                                             ---------  ---------  -------------
                                                             ---------  ---------  -------------
</TABLE>
 
    Included in property and equipment at December 31, 1996 and 1997 and
September 30, 1998 were assets acquired under capital lease obligations with a
cost of approximately $2,302,000, $3,076,000 and $5,354,000. Accumulated
depreciation related to the assets acquired under capital leases totaled
$319,000, $1,174,000 and $2,220,000 at December 31, 1996 and 1997 and September
30, 1998.
 
                                      F-21
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
5. INTANGIBLE ASSETS
 
    Intangible assets consist of the following (in thousands):
 
<TABLE>
<CAPTION>
                                                              DECEMBER 31,
                                           AMORTIZATION  ----------------------
                                              PERIOD        1996        1997
                                           ------------  ----------  ----------  SEPTEMBER 30,
                                                                                     1998
                                                                                 -------------
                                                                                  (UNAUDITED)
<S>                                        <C>           <C>         <C>         <C>
Services agreements......................      3 years   $    2,855  $    2,855    $   2,855
Software technology rights...............      3 years        8,333      17,664       23,107
Internally developed software............      3 years        1,001       1,292           --
Trademarks...............................      3 years          216         216          216
Goodwill.................................      3 years        8,012       8,012       15,668
Other....................................    2-3 years        1,541       1,541        2,924
                                                         ----------  ----------  -------------
                                                             21,958      31,580       44,770
Less accumulated amortization............                    (5,403)    (12,812)     (21,028)
                                                         ----------  ----------  -------------
                                                         $   16,555  $   18,768    $  23,742
                                                         ----------  ----------  -------------
                                                         ----------  ----------  -------------
</TABLE>
 
6. COMMITMENTS
 
    Healtheon has entered into several lease lines of credit. Lease lines
totaling $3,500,000 and $2,000,000 were entered into during the years ended
December 31, 1996 and 1997. Approximately $2,900,000 and $5,135,000 had been
utilized under these lease lines through December 31, 1997 and September 30,
1998. At September 30, 1998, approximately $1,266,000 was available for future
utilization under these lease lines. This amount included approximately $901,000
that was repaid under the terms of a revolving lease line and is thus again
available for future utilization. The arrangements are secured by the property
and equipment subject to the leases. The term of the leases is generally three
years and the interest rates implicit in the leases range from 16.9% to 20.2%
per annum. Information on payments due under these lease lines is included in
the table below under "Capital Leases."
 
    We lease our headquarters and other office facilities under operating lease
agreements that expire at various dates through 2008. Total rent expense for all
operating leases was approximately $391,000, $953,000, $1,646,000, $1,165,000
and $1,616,000 for the years ended December 31, 1995, 1996 and 1997 and the nine
months ended September 30, 1997 and 1998. These amounts are net of sublease
income from a related party of approximately $30,000, $68,000, $58,000, $42,000
and $43,000. Future minimum lease
 
                                      F-22
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
6. COMMITMENTS (CONTINUED)
commitments under noncancellable lease agreements at December 31, 1997 were as
follows (in thousands):
 
<TABLE>
<CAPTION>
                                                              OPERATING LEASES  CAPITAL LEASES
                                                              ----------------  ---------------
<S>                                                           <C>               <C>
Year ending December 31,
  1998......................................................     $    2,444        $   1,167
  1999......................................................          2,423              858
  2000......................................................          2,077              164
  2001......................................................          1,506               --
  2002......................................................            963               --
  Thereafter................................................          4,978               --
                                                                    -------           ------
Total minimum lease payments................................     $   14,391            2,189
                                                                    -------
                                                                    -------
Amount representing interest................................                            (219)
                                                                                      ------
Present value of minimum lease payments under capital lease
  obligations...............................................                           1,970
Less current portion........................................                          (1,038)
                                                                                      ------
Non-current portion.........................................                       $     932
                                                                                      ------
                                                                                      ------
</TABLE>
 
7. BRIDGE LOANS AND NOTE RECEIVABLE FROM OFFICER
 
    In 1997, Healtheon borrowed $2,000,000 from certain stockholders in the form
of 6% convertible promissory notes in contemplation of the Series C convertible
preferred stock offering. These notes were converted into 800,000 shares of
Series C convertible preferred stock upon the closing of that offering. Warrants
to purchase 61,947 shares of Series B convertible preferred stock were issued in
connection with the Notes (see Note 10).
 
    In July 1997, in consideration of 250,000 shares of Series B convertible
preferred stock issued to an officer, we received a one-year, full-recourse,
noninterest-bearing promissory note for $500,000. At December 31, 1997, $349,000
remained outstanding under the note. At September 30, 1998, the note had been
paid in full.
 
    In February 1998, we entered into a $2,000,000 line of credit agreement with
a stockholder. We borrowed $1,000,000 under the agreement, which was repaid with
interest at 10% per annum in May 1998.
 
8. LINES OF CREDIT
 
    In September 1997, Healtheon entered into a line of credit agreement with a
bank that allows us to borrow up to $2,101,000. Amounts borrowed under this
agreement bear interest at the bank's prime rate (8.5% at December 31, 1997 and
September 30, 1998). Interest is payable monthly with payments commencing on
September 30, 1997. The line of credit availability declines over the term to
$1,821,000, $1,215,000 and $547,000 at December 31, 1997, 1998 and 1999, and
expires on September 5, 2000. The amount outstanding is collateralized by
certain assets. At December 31, 1997 and September 30, 1998, $1,415,000 was
outstanding under the agreement.
 
                                      F-23
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
8. LINES OF CREDIT (CONTINUED)
    In December 1997, we entered into a loan agreement with a bank that allowed
us to borrow up to $2,250,000. Amounts borrowed under this loan agreement bear
interest at the bank's prime rate (8.5% at December 31, 1997 and September 30,
1998). The loan was personally guaranteed by a stockholder until the acquisition
of ActaMed in May 1998. In May 1998, concurrent with the removal of the
stockholder guarantee, the interest rate was increased to the bank's prime rate
plus 1.5%. Interest is payable monthly with payments commencing on January 31,
1998. At December 31, 1997, $2,000,000 was outstanding under the loan agreement.
The principal balance of the loan was repaid in full in August 1998.
 
9. CONVERTIBLE REDEEMABLE PREFERRED STOCK
 
    A summary of ActaMed's 8% cumulative convertible redeemable preferred stock
is as follows.
 
<TABLE>
<CAPTION>
                                                           DECEMBER 31,
                                     --------------------------------------------------------
                                                1996                         1997
                                     ---------------------------  ---------------------------
                                        ISSUED                       ISSUED
                          SHARES         AND        LIQUIDATION       AND        LIQUIDATION
                        AUTHORIZED   OUTSTANDING    PREFERENCE    OUTSTANDING    PREFERENCE
                       ------------  ------------  -------------  ------------  -------------
<S>                    <C>           <C>           <C>            <C>           <C>
Series A.............     5,519,912     5,519,912  $   9,825,000     5,519,912  $  10,458,000
Series B.............     2,162,759     2,162,759      7,614,000     2,162,759      8,171,000
Series C.............     6,488,276     6,488,276     22,257,000     6,488,276     23,936,000
Series D.............     2,317,913            --             --     2,317,913      8,500,000
                       ------------  ------------  -------------  ------------  -------------
                         16,488,860    14,170,947  $  39,696,000    16,488,860  $  51,065,000
                       ------------  ------------  -------------  ------------  -------------
                       ------------  ------------  -------------  ------------  -------------
</TABLE>
 
    In March 1998, an additional 763,548 shares of Series D convertible
redeemable preferred stock were issued in connection with the asset acquisition
from SmithKline Labs (see Note 3).
 
    Dividends on each Series were cumulative whether or not declared and are
shown as a charge against income in the accompanying financial statements. On
May 19, 1998, in connection with the acquisition of ActaMed by Healtheon, the
convertible redeemable preferred stockholders waived payment of all accrued and
unpaid dividends.
 
    Preferred holders voted generally on an as-if converted basis. In addition,
a majority approval of the four Series was required to approve certain
transactions.
 
    The Series A, B, C and D cumulative convertible redeemable preferred
stockholders were entitled to receive, upon liquidation, an amount per share
equal to the issuance price, plus all accrued but unpaid dividends. Common
stockholders would then have received $5,000,000. Any remaining proceeds would
then have been distributed pro rata to the stockholders, subject only to the
Series A holders' right to receive sufficient funds to provide a 20% return on
their original investment.
 
    Each Series was redeemable at up to one-third of the originally issued
shares per year commencing in years six, seven and eight after the issue date at
a redemption price equal to the issue price plus all accrued but unpaid
dividends. On May 19, 1998, all outstanding shares of convertible redeemable
preferred stock were converted into 17,252,408 shares of common stock in
connection with the acquisition of ActaMed by Healtheon.
 
                                      F-24
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
10. STOCKHOLDERS' EQUITY
 
    CONVERTIBLE PREFERRED STOCK
 
    Healtheon was authorized to issue 48,020,000 shares of convertible preferred
stock, designated in series. A summary of convertible preferred stock was as
follows:
 
<TABLE>
<CAPTION>
                                                           DECEMBER 31,
                                     --------------------------------------------------------
                                                1996                         1997
                                     ---------------------------  ---------------------------
                                        ISSUED                       ISSUED
                          SHARES         AND        LIQUIDATION       AND        LIQUIDATION
                        DESIGNATED   OUTSTANDING    PREFERENCE    OUTSTANDING    PREFERENCE
                       ------------  ------------  -------------  ------------  -------------
<S>                    <C>           <C>           <C>            <C>           <C>
Series A.............    10,305,000    10,285,000  $   5,143,000    10,305,000  $   5,153,000
Series B.............     6,105,000     3,000,000      6,000,000     3,290,000      6,580,000
Series C.............     2,600,000            --             --     2,600,000      6,500,000
Series D.............     5,000,000            --             --     4,807,692     25,000,000
                       ------------  ------------  -------------  ------------  -------------
                         24,010,000    13,285,000  $  11,143,000    21,002,692  $  43,233,000
                       ------------  ------------  -------------  ------------  -------------
                       ------------  ------------  -------------  ------------  -------------
</TABLE>
 
    Series A and Series B convertible preferred shares included 20,000 and
25,000 shares, respectively, that were issued for services rendered.
 
    On May 19, 1998, all outstanding shares of convertible preferred stock were
converted into shares of common stock on a one-for-one basis at the election of
the holders in connection with Healtheon's acquisition of ActaMed. Concurrently
with the conversion, all outstanding warrants to purchase Series B preferred
stock were converted into warrants to purchase the same number of shares of
common stock.
 
    Series A, B, C and D convertible preferred stockholders were entitled to
noncumulative dividends of $0.03375, $0.135, $0.16875 and $0.351, respectively,
per share per annum. No dividends were declared through the date of conversion.
The Series A, B, C and D convertible preferred stockholders were entitled to
receive, upon liquidation, an amount per share equal to the issuance price, plus
all declared but unpaid dividends. The Series A, B, C and D convertible
preferred stockholders had voting rights equal to the common shares issuable
upon conversion.
 
    PREFERRED STOCK
 
    In July 1998, the Board of Directors approved a resolution authorizing
Healtheon to issue up to 5,000,000 shares of preferred stock, to be effective
upon the effective date of our initial public offering.
 
    WARRANTS
 
    In November 1996, Healtheon issued a warrant to a venture capital investor
to purchase 1,000,000 shares of Series B convertible preferred stock at an
exercise price of $2.00 per share for services rendered by the investor on
Healtheon's behalf. A then partner of the venture capital firm assumed the role
of President and Chief Executive Officer for Healtheon from our inception
through June 1997. The warrant was immediately exercisable and expires three
years from the date of issuance. We recorded a charge of $500,000 representing
the fair value of the warrant issued and services received based on a valuation
obtained from an independent appraiser utilizing a modified Black-Scholes option
pricing model. This
 
                                      F-25
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
10. STOCKHOLDERS' EQUITY (CONTINUED)
warrant was outstanding at December 31, 1997 and in May 1998 was converted to a
warrant to purchase common stock. It remained outstanding at September 30, 1998.
 
    In November 1996, we granted a warrant to one of our directors to purchase
1,000,000 shares of Series B convertible preferred stock at an exercise price of
$2.00 per share, the fair value of Series B convertible preferred stock at the
date of issuance. The warrant vests over a period of 18 months from the date of
issuance. The term of the warrant is three years. This warrant was outstanding
at December 31, 1997 and was exercised in full in May 1998.
 
    In December 1996, we issued a warrant to a customer to purchase 282,522
shares of common stock at a price of $7.97 per share. The warrant expires in
December 2001. This warrant was outstanding at September 30, 1998.
 
    In July 1997, we issued a warrant to an officer, in connection with his
employment, to purchase 750,000 shares of Series B convertible preferred stock
at an exercise price of $2.00 per share, the fair value of Series B convertible
preferred stock at the date of issuance. The warrant expires three years from
issuance, and shares purchased under the warrant are subject to repurchase by
Healtheon, at our option, upon termination of employment. Shares under the
warrant vest ratably over a period of two years from the date of grant. This
warrant was outstanding at December 31, 1997 and in May 1998 was converted to a
warrant to purchase common stock. It remained outstanding at September 30, 1998.
 
    In July 1997, we issued warrants to purchase a total of 61,947 shares of
Series B convertible preferred stock to certain investors in connection with a
bridge financing. The warrants expire four years from issuance and are
exercisable at $2.00 per share. The value of these warrants, approximately
$64,000, was expensed as a cost of financing. All of these warrants were
outstanding at December 31, 1997. In May 1998, warrants to purchase 17,229
shares of Series B convertible preferred stock were exercised and the remainder
of the warrants, which were outstanding at September 30, 1998, were converted to
warrants to purchase 44,718 shares of common stock.
 
    At December 31, 1997 we had reserved 2,811,947 shares of our Series B
preferred stock and 282,522 shares of our common stock for issuance upon
exercise of outstanding warrants. In conjunction with the acquisition of ActaMed
in May 1998, all outstanding warrants to purchase Series B preferred stock were
converted into warrants to purchase common stock. At September 30, 1998, we had
reserved 2,077,240 shares of our common stock for issuance upon exercise of the
outstanding warrants for common stock.
 
                                      F-26
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
10. STOCKHOLDERS' EQUITY (CONTINUED)
 
    In December 1998, as part of a service agreement with a customer, we issued
to the customer a warrant to purchase 500,000 shares of common stock with an
exercise price of $10.40 per share. (See Note 14).
 
11. STOCK-BASED COMPENSATION
 
    STOCK OPTION PLANS
 
    Under the 1996 Stock Plan, or the 1996 Plan, which was adopted in February
1996, the Board of Directors may grant options to purchase common stock or issue
common stock subject to a restricted stock purchase agreement to eligible
participants. At December 31, 1997, a total of 9,000,000 shares had been
reserved under the 1996 Plan. In March 1998, the Board of Directors and the
stockholders approved an increase in the reserve of 1,000,000 shares. In July
1998, the Board of Directors approved, subject to stockholder approval, an
additional increase in the reserve of 5,000,000 shares to a total of 15,000,000
shares reserved, plus annual increases equal to the lesser of 5% of the
outstanding common shares or a lesser amount determined by the Board of
Directors. Options granted may be either incentive stock options or nonstatutory
stock options and are exercisable within the times or upon the events determined
by the Board of Directors as specified in each option agreement. Options vest
over a period of time as determined by the Board of Directors, generally four
years. The term of the 1996 Plan is ten years. At December 31, 1997 and
September 30, 1998, 274,166 and 1,715,853 shares remained available for future
grant under the 1996 Plan.
 
    In connection with the acquisition of ActaMed, Healtheon assumed all the
outstanding options issued under the ActaMed stock option plans, after the
application of the exchange ratio, and reserved 3,100,489 shares of common stock
for issuance upon exercise of the assumed options. No further options can be
granted under these plans. At the time of the acquisition, options for 2,717,269
shares were fully vested. The remainder of the shares vest based upon annual
cliffs over a five-year period from the date of grant.
 
    During the years ended December 31, 1996 and 1997 and the nine-month period
ended September 30, 1998, we issued approximately 1,806,000, 850,000 and 530,000
shares of common stock subject to restricted stock purchase agreements to
employees for cash. The common stock is subject to repurchase at the original
exercise price until vested, at our option, and approximately 614,000 shares
were repurchased from terminated employees during the year ended December 31,
1997. The shares vest over a period of time as determined by the Board of
Directors for each individual purchase agreement, generally four years. At
December 31, 1996 and 1997 and September 30, 1998, approximately 1,660,000,
1,430,000 and 1,501,000 shares, respectively, were subject to repurchase.
 
                                      F-27
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
11. STOCK-BASED COMPENSATION (CONTINUED)
    The following table summarizes stock option activity:
 
<TABLE>
<CAPTION>
                                                                                                  WEIGHTED-AVERAGE
                                                                                  NUMBER OF      EXERCISE PRICE PER
                                                                                   SHARES               SHARE
                                                                              -----------------  -------------------
<S>                                                                           <C>                <C>
ACTAMED CORPORATION
Outstanding at January 1, 1995..............................................        4,223,214         $     .34
  Granted...................................................................          856,000               .91
  Exercised.................................................................       (1,071,250)              .02
  Canceled..................................................................          (62,750)              .83
                                                                              -----------------
Options outstanding at December 31, 1995....................................        3,945,214         $     .55
                                                                              -----------------
                                                                              -----------------
HEALTHEON CORPORATION
Options outstanding at December 31, 1995 (reflecting the exchange ratio of
  .6272)....................................................................        2,474,438         $     .88
  Granted...................................................................        3,004,384               .54
  Exercised.................................................................             (300)              .05
  Canceled..................................................................         (233,907)              .78
                                                                              -----------------
Options outstanding at December 31, 1996....................................        5,244,615               .68
  Granted...................................................................        5,394,008               .73
  Exercised.................................................................         (547,844)              .16
  Canceled..................................................................         (890,528)              .49
                                                                              -----------------
Options outstanding at December 31, 1997....................................        9,200,251               .72
  Granted (unaudited).......................................................        4,756,006              4.47
  Exercised (unaudited).....................................................       (2,247,606)              .59
  Canceled (unaudited)......................................................         (522,178)             1.01
                                                                              -----------------
Options outstanding at September 30, 1998 (unaudited).......................       11,186,473         $    2.33
                                                                              -----------------
                                                                              -----------------
</TABLE>
 
<TABLE>
<CAPTION>
                                                                          ACTAMED
                                                                        CORPORATION             HEALTHEON CORPORATION
                                                                      ---------------  ---------------------------------------
                                                                                                                NINE MONTHS
                                                                        YEAR ENDED         YEARS ENDED             ENDED
                                                                       DECEMBER 31,        DECEMBER 31,        SEPTEMBER 30,
                                                                      ---------------  --------------------  -----------------
                                                                           1995          1996       1997           1998
                                                                      ---------------  ---------  ---------  -----------------
<S>                                                                   <C>              <C>        <C>        <C>
                                                                                                                (UNAUDITED)
Weighted-average fair value of options granted......................     $     .28     $     .15  $     .18      $     .75
                                                                               ---           ---        ---            ---
                                                                               ---           ---        ---            ---
</TABLE>
 
                                      F-28
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
11. STOCK-BASED COMPENSATION (CONTINUED)
    The following table summarizes information regarding options outstanding and
exercisable at December 31, 1997:
 
<TABLE>
<CAPTION>
                                                                                  WEIGHTED-
                                                                                   AVERAGE
                                                                                  REMAINING                  WEIGHTED-
                                                                 WEIGHTED-       CONTRACTUAL                  AVERAGE
                                                                  AVERAGE           LIFE          NUMBER     EXERCISE
EXERCISE PRICES                          NUMBER OUTSTANDING   EXERCISE PRICE     (IN YEARS)     EXERCISABLE    PRICE
- ---------------------------------------  -------------------  ---------------  ---------------  ----------  -----------
<S>                                      <C>                  <C>              <C>              <C>         <C>
$ .03 -  $.08..........................        2,490,007         $     .05             6.98      1,679,870   $     .04
$ .20 -  $.25..........................        3,693,879               .24             9.53        682,500         .20
$1.00 - $1.45..........................        2,092,187              1.24             9.69        794,213        1.45
$3.24..................................          924,178              3.24             7.94         76,644        3.24
                                              ----------                                        ----------
                                               9,200,251         $     .72             8.63      3,233,227   $     .50
                                              ----------                                        ----------
                                              ----------                                        ----------
</TABLE>
 
    We recorded deferred stock compensation of approximately $2,713,000 and
$4,083,000 during the year ended December 31, 1997 and the nine months ended
September 30, 1998, respectively. These amounts represented the difference
between the exercise price and the deemed fair value of our common stock on the
date such stock options were granted. We recorded amortization of deferred stock
compensation of approximately $562,000 and $2,050,000 during these periods based
on a graded vesting method. At September 30, 1998, we had a total of
approximately $4,184,000 remaining to be amortized on a graded vesting method
over the corresponding vesting period of each respective option, generally four
years.
 
    PRO FORMA INFORMATION
 
    We have elected to follow APB No. 25 and related interpretations in
accounting for its employee stock options because, as discussed below, the
alternative fair value accounting provided for under SFAS No. 123 requires use
of option valuation models that were not developed for use in valuing employee
stock options. Under APB No. 25, no compensation expense is recognized when the
exercise price of stock options granted to our employees equals the market price
of the underlying stock on the date of grant.
 
    Pro forma information regarding net loss is required by SFAS No. 123 and has
been determined as if employee stock options granted subsequent to December 31,
1994 were accounted for under the fair value method of SFAS No. 123. The fair
value for these options was estimated at the date of grant using the minimum
value method with the following weighted-average assumptions for the years ended
December 31, 1995, 1996 and 1997 and the nine months ended September 30, 1998:
risk-free interest rate
 
                                      F-29
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
11. STOCK-BASED COMPENSATION (CONTINUED)
of approximately 6.2%, 6.0%, 6.0% and 5.4%; a weighted-average expected life of
the option of 5.0 years, 4.3 years, 4.2 years and 3.5 years; and a dividend
yield of zero for all periods.
 
<TABLE>
<CAPTION>
                                                                                    HEALTHEON CORPORATION
                                                                 ACTAMED     ------------------------------------
                                                               CORPORATION
                                                               ------------       YEARS ENDED        NINE MONTHS
                                                                YEAR ENDED        DECEMBER 31,          ENDED
                                                               DECEMBER 31,  ----------------------  SEPTEMBER 30
                                                                   1995         1996        1997         1998
                                                               ------------  ----------  ----------  ------------
<S>                                                            <C>           <C>         <C>         <C>
                                                                                                     (UNAUDITED)
Net loss applicable to common stockholders (in thousands):
  As reported................................................   $   (4,458)  $  (18,606) $  (28,005)  $  (35,860)
                                                               ------------  ----------  ----------  ------------
                                                               ------------  ----------  ----------  ------------
  Pro forma..................................................   $   (4,488)  $  (18,695) $  (28,173)  $  (36,892)
                                                               ------------  ----------  ----------  ------------
                                                               ------------  ----------  ----------  ------------
Basic and diluted net loss per common share:
  As reported................................................   $     (.85)  $    (2.83) $    (3.88)  $    (1.24)
                                                               ------------  ----------  ----------  ------------
                                                               ------------  ----------  ----------  ------------
  Pro forma..................................................   $     (.86)  $    (2.84) $    (3.90)  $    (1.28)
                                                               ------------  ----------  ----------  ------------
                                                               ------------  ----------  ----------  ------------
</TABLE>
 
    In September 1998, the Board of Directors approved and in October 1998, the
stockholders also approved the adoption of Healtheon's 1998 Employee Stock
Purchase Plan, or the 1998 Purchase Plan, to be effective on the effective date
of our initial public offering. A total of 1,000,000 shares of common stock has
been reserved for issuance under the 1998 Purchase Plan, plus annual increases
equal to the lesser of 500,000 shares, 0.5% of the outstanding common shares or
a lesser amount determined by the Board of Directors.
 
12. INCOME TAXES
 
    Deferred income taxes reflect the net tax effects of temporary differences
between the carrying amounts of assets and liabilities for financial reporting
purposes and the amounts used for income tax
 
                                      F-30
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
12. INCOME TAXES (CONTINUED)
purposes. Significant components of Healtheon's deferred tax assets
(liabilities) were as follows (in thousands):
 
<TABLE>
<CAPTION>
                                                                               DECEMBER 31,
                                                                           --------------------
                                                                             1996       1997
                                                                           ---------  ---------
<S>                                                                        <C>        <C>
Deferred tax assets:
  Net operating loss carryforwards.......................................  $   7,537  $  14,263
  Intangible assets......................................................      1,580      3,688
  Research and development tax credit....................................        561      1,014
  Reserves and accruals not currently deductible.........................        227        308
                                                                           ---------  ---------
Total deferred tax assets................................................      9,905     19,273
Valuation allowance......................................................     (9,545)   (18,931)
                                                                           ---------  ---------
Net deferred tax assets..................................................        360        342
                                                                           ---------  ---------
Deferred tax liabilities
  Depreciation...........................................................        (31)       (45)
  Capitalized software development costs.................................       (329)      (297)
                                                                           ---------  ---------
Total deferred tax liabilities...........................................       (360)      (342)
                                                                           ---------  ---------
Net deferred tax assets and liabilities..................................  $      --  $      --
                                                                           ---------  ---------
                                                                           ---------  ---------
</TABLE>
 
    A valuation allowance equal to 100% of the net deferred tax assets has been
established because of the uncertainty of realization of the deferred tax assets
due to our lack of earnings history. The valuation allowance for deferred tax
assets increased by $6,580,000 and $9,386,000 during the years ended December
31, 1996 and 1997.
 
    At December 31, 1997, we had net operating loss carryforwards for federal
income tax purposes of approximately $37,575,000, which expire in 2009 through
2012, and federal tax credits of approximately $800,000, which expire in 2009
through 2012.
 
    Approximately $16,675,000 of the net operating loss at December 31, 1997
related to a consolidated subsidiary. This loss carryforward is only available
to offset future taxable income of that subsidiary.
 
    Because of the "change of ownership" provisions of the Internal Revenue
Code, a portion of our net operating loss carryforwards and tax credit
carryforwards may be subject to an annual limitation regarding their utilization
against taxable income in future periods. A portion of these carryforwards may
expire before becoming available to reduce future income tax liabilities.
 
13. RELATED PARTY TRANSACTIONS
 
    Healtheon has two customers that are significant stockholders of Healtheon.
 
    We entered into a Development Agreement with a partnership controlled by the
former Chairman of the Board of Directors of ActaMed. Pursuant to this
agreement, we granted the partnership exclusive licenses to use ActaMed's
technology for industries other than the health care industry. Under the
agreement, we will receive a commercial royalty on the partnership's gross
receipts. If we desire in the
 
                                      F-31
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
13. RELATED PARTY TRANSACTIONS (CONTINUED)
future to expand to other industries, the partnership must either develop that
industry in a defined time period or rights to that industry revert to
Healtheon. The agreement expires December 3, 1998 and to date no fees have been
paid to Healtheon under this agreement.
 
    We share office space and provide administrative support and network
resources to a company controlled by a member of the Board of Directors. Amounts
reimbursed for the shared facilities and administrative support totaled
approximately $62,000, $58,000, $46,000, $36,000 and $51,000 for the years ended
December 31, 1995, 1996, and 1997 and the nine months ended September 30, 1997
and 1998. Approximately $211,000, $187,000, $78,000 and $41,000 was reimbursed
during the years ended December 31, 1995, 1996 and 1997 and the nine months
ended September 30, 1997 for the use of the network maintained by Healtheon. No
income for the use of the network by the related party was recognized for the
nine months ended September 30, 1998. All such amounts are included as an offset
to general and administrative expenses in the accompanying consolidated
statements of operations. Amounts due from the related party of $33,000 and
$72,000 at December 31, 1996 and 1997 were included in other current assets in
the accompanying consolidated balance sheets. There were no amounts due from the
related party at September 30, 1998.
 
14. SUBSEQUENT EVENTS (UNAUDITED)
 
    From October 1998 through February 1999, Healtheon granted to employees
options to purchase common stock and issued shares of common stock under
restricted stock purchase agreements equal to a total of 5,625,882 shares of
common stock at exercise or purchase prices ranging from $3.55 to $5.85 per
share. We estimate that we will record additional deferred stock compensation of
approximately $7,000,000 with regard to these grants.
 
    On October 20, 1998, we offered our employees who were granted options
between July 1998 through October 1998 the ability to cancel their original
option grant in exchange for a new option agreement with a new vesting start
date and option price of $3.55 per share. A total of 3,380,200 option shares
with exercise prices of $4.50, $6.30, $7.00 and $8.00 were eligible to be
repriced. A total of 2,057,950 option shares were cancelled and reissued. In
addition, on December 14, 1998, 455,000 shares of common stock issued in July
1998 pursuant to restricted stock purchase agreements with purchase prices of
$4.55 to $7.00 per share were rescinded. We estimate that we will record
additional deferred stock compensation of approximately $2,700,000 as a result
of this repricing.
 
    In December 1998, we issued to a customer a warrant to purchase 500,000
shares of common stock at an exercise price of $10.40 per share.
 
    In October 1998, Healtheon withdrew its registration statement for its
initial public offering. Accordingly, in the fourth quarter of 1998, Healtheon
will record a charge of approximately $1.6 million related to the costs of the
withdrawn offering.
 
    In October 1998, the Board of Directors authorized 8,285,007 shares of
convertible preferred stock and designated all of these shares as Series A. In
November 1998, we issued 7,683,341 shares of Series A convertible preferred
stock for $46,100,000 of cash proceeds. The Series A convertible preferred
stockholders are entitled to non-cumulative dividends of $.405 per share per
annum, and liquidation rights per share equal to the issuance price plus all
declared but unpaid dividends. Each share of Series A
 
                                      F-32
<PAGE>
                             HEALTHEON CORPORATION
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
      (INFORMATION AS OF SEPTEMBER 30, 1998 AND FOR THE NINE MONTHS ENDED
 
                   SEPTEMBER 30, 1997 AND 1998 IS UNAUDITED)
 
14. SUBSEQUENT EVENTS (UNAUDITED) (CONTINUED)
preferred stock is convertible into one share of common stock. The Series A
preferred stock has voting rights equal to the common stock issuable upon
conversion. The holders of Series A preferred stock have agreed to convert all
of the outstanding shares of Series A preferred stock to common stock effective
upon the closing of our initial public offering.
 
    Also in October 1998, the Board of Directors approved an increase in the
number of shares of common stock authorized for issuance to 150,000,000 shares.
 
    In January 1998, Healtheon and SmithKline Labs entered into a services
agreement under which Healtheon will provide certain electronic laboratory
results delivery services to approximately 20,000 provider sites, in addition to
the sites currently served through the SCAN service. In addition, in January
1999, the two companies completed an asset purchase agreement under which
Healtheon purchased certain assets currently used by SmithKline Labs to provide
these laboratory results delivery services in exchange for $2,000,000 in cash
and 1,833,333 shares of Healtheon's common stock with a value of $11,000,000.
 
    In January 1999, an additional 3,107,321 shares were reserved under the 1996
Plan under the annual increase provision. In February 1999, the Board of
Directors and the stockholders approved an amendment to increase the number of
shares reserved for issuance under the 1996 Plan by an additional 1,000,000
shares.
 
                                      F-33
<PAGE>
                          INDEPENDENT AUDITORS' REPORT
 
Board of Directors of United HealthCare Corporation:
 
    We have audited the accompanying statements of divisional net loss and
United HealthCare Corporation's ("United's") net investment and of divisional
cash flows for the year ended December 31, 1995 of EDI Services Group ("EDI") (a
Division of United.) These statements of divisional net loss and United's net
investment and of divisional cash flows are the responsibility of United's
management. Our responsibility is to express an opinion on these statements of
divisional net loss and United's net investment and of divisional cash flows
based on our audit.
 
    We conducted our audit in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the statements of divisional net loss and
United's net investment and of divisional cash flows are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the statements of divisional net loss and
United's net investment and of divisional cash flows. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall statements of divisional net loss
and United's net investment and of divisional cash flows presentation. We
believe that our audit provides a reasonable basis for our opinion.
 
    The accompanying statements of divisional net loss and United's net
investment and of divisional cash flows reflect a component of a business
enterprise that was derived from a consolidated group of companies rather than a
complete legal entity. See Note 1 to the statements of divisional net loss and
United's net investment and of divisional cash flows for a description of the
basis of presentation.
 
    In our opinion, the statements of divisional net loss and United's net
investment and of divisional cash flows present fairly, in all material
respects, the results of its divisional net loss and United's net investment and
of divisional cash flows for the year ended December 31, 1995, in conformity
with generally accepted accounting principles.
 
DELOITTE & TOUCHE LLP
 
Minneapolis, Minnesota
April 4, 1996
 
                                      F-34
<PAGE>
                               EDI SERVICES GROUP
                 (A DIVISION OF UNITED HEALTHCARE CORPORATION)
 
          STATEMENT OF DIVISIONAL NET LOSS AND UNITED'S NET INVESTMENT
                          YEAR ENDED DECEMBER 31, 1995
 
<TABLE>
<S>                                                                               <C>
Revenue:
  Related-party processing revenue..............................................  $2,900,448
  Related-party site revenue....................................................  1,155,300
  Other processing revenue......................................................    100,013
                                                                                  ---------
      Total revenue.............................................................  4,155,761
Operating costs and expenses:
  Cost of revenues..............................................................  1,646,039
  Sales and marketing...........................................................    302,145
  Research and development......................................................  1,604,897
  General and administrative....................................................    642,980
                                                                                  ---------
      Total operating costs and expenses........................................  4,196,061
                                                                                  ---------
Loss before income taxes........................................................    (40,300)
Income taxes....................................................................     48,177
                                                                                  ---------
      Net loss..................................................................    (88,477)
United's net investment--Beginning of period....................................    124,393
Net cash flows to EDI division..................................................    417,213
                                                                                  ---------
United's net investment--end of period..........................................  $ 453,129
                                                                                  ---------
                                                                                  ---------
</TABLE>
 
                       See notes to financial statements.
 
                                      F-35
<PAGE>
                               EDI SERVICES GROUP
                 (A DIVISION OF UNITED HEALTHCARE CORPORATION)
 
                       STATEMENT OF DIVISIONAL CASH FLOWS
                          YEAR ENDED DECEMBER 31, 1995
 
<TABLE>
<S>                                                                                <C>
Operating activities:
  Net loss.......................................................................  $ (88,477)
  Adjustments to reconcile net loss to net cash provided by operating activities:
    Depreciation and amortization................................................    285,613
    Increase in deferred income taxes............................................     48,177
    Changes in assets and liabilities:
      Accounts receivable........................................................    (13,347)
      Accounts payable...........................................................    (58,612)
      Accrued expenses...........................................................    (46,083)
                                                                                   ---------
        Net cash provided by operating activities................................    127,271
                                                                                   ---------
Investing activities:
  Purchase of property...........................................................   (190,375)
  Software development costs.....................................................   (354,109)
                                                                                   ---------
        Net cash used in investing activities....................................   (544,484)
                                                                                   ---------
Net cash flows of division which were provided by United.........................  $(417,213)
                                                                                   ---------
                                                                                   ---------
</TABLE>
 
                       See notes to financial statements.
 
                                      F-36
<PAGE>
                               EDI SERVICES GROUP
                 (A DIVISION OF UNITED HEALTHCARE CORPORATION)
 
                         NOTES TO FINANCIAL STATEMENTS
 
                      FOR THE YEAR ENDED DECEMBER 31, 1995
 
1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
 
    NATURE OF BUSINESS--EDI Services Group ("EDI") is an operating division of
United HealthCare Corporation ("United"). EDI was established to develop and
market software to control a network that facilitates the exchange of health
care information among managed care organizations, insurance carriers,
hospitals, physicians, and other health care industry participants. On December
15, 1995, United transferred EDI and its ProviderLink operations to a holding
company, UHC Green Acquisition Inc. ("UHC Green") (a wholly owned subsidiary of
United).
 
    BASIS OF PRESENTATION--The accompanying statements of divisional net loss
and United's net investment and divisional cash flows have been prepared from
the books and records maintained by EDI and United. The statement of divisional
net loss may not necessarily be indicative of the results of operations that
would have been obtained if EDI had been operated as an independent entity. The
statement of divisional net loss includes allocation of certain expenses that
are material in amount. Such expenses are allocations for corporate services and
overhead.
 
    Intercompany revenue results from network services provided to health plans
owned or managed by United.
 
    The accompanying financial statements have been prepared on a going-concern
basis, which contemplates the realization of assets and liabilities in the
normal course of business. As shown in the financial statements, during the year
ended December 31, 1995, EDI incurred a net loss of approximately $88,000 and a
cash flow deficit of approximately $417,000.
 
    As discussed in Note 5, EDI was acquired by ActaMed Corporation ("ActaMed")
effective March 31, 1996. EDI's continued existence is dependent on funding of
its cash flow deficit by ActaMed and on its relationship and service agreement
with United. The service agreement states that the combined entities will be the
primary provider of electronic data interchange services for United for a period
of five years.
 
    The nature of EDI's operations exposes EDI to certain business risks. Such
business risks include EDI's concentration of sales transactions with United,
which accounted for 98% of EDI's 1995 revenues (see Note 4). The market for
health care information services is highly competitive and subject to rapid
technological change, evolving industry standards, and regulatory developments
and influences that may affect both the operations of EDI and its customers. In
addition, significant demands may be placed on EDI's management as a result of
EDI's merger with ActaMed (see Note 5). Other significant business risks faced
by EDI include a dependence on key employees and the risk of liability
associated with unforeseen software product errors.
 
    The preparation of financial statements in conformity with generally
accepted accounting principles requires management to make estimates and
assumptions that affect the reported amounts of revenues and expenses during the
reporting period. Actual results could differ from those estimates.
 
SIGNIFICANT ACCOUNTING POLICIES
 
    INCOME TAXES--United provides for income taxes under the provisions of SFAS
No. 109, "Accounting for Income Taxes," which requires deferred income tax
balances to be computed annually for differences between financial statement and
tax bases of assets and liabilities based on enacted tax rates. An income tax
provision has been allocated to EDI as if EDI filed on a separate return basis;
however, under the
 
                                      F-37
<PAGE>
                               EDI SERVICES GROUP
                 (A DIVISION OF UNITED HEALTHCARE CORPORATION)
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
                      FOR THE YEAR ENDED DECEMBER 31, 1995
 
1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
income tax allocation agreement policy with United, no benefit is allocated for
losses incurred which are utilized in the consolidated income tax return (see
Note 2).
 
    UNITED'S NET INVESTMENT--United's net investment, as shown in the
accompanying statement of divisional net loss and United's net investment,
represents losses incurred by EDI since inception and the intercompany account
with United that consists of transactions with United and the net cash flows of
EDI, which have been funded by United.
 
    REVENUE RECOGNITION--EDI earns revenue from providing access to its network
services, including fixed fee and transaction-based services. EDI recognizes
revenue from network services over the period the services are provided.
 
2. INCOME TAXES
 
    Components of income tax expense for the year ended December 31, 1995 were:
 
<TABLE>
<S>                                                                                  <C>
Deferred:
  State............................................................................  $  11,666
  Federal..........................................................................     36,511
                                                                                     ---------
                                                                                     $  48,177
                                                                                     ---------
                                                                                     ---------
</TABLE>
 
    Differences between the provision for income taxes at the federal statutory
rate and the recorded provision for the year ended December 31, 1995 are
summarized as follows:
 
<TABLE>
<S>                                                                                 <C>
Benefit at statutory rate.........................................................  $ (13,610)
State income taxes................................................................     (2,590)
Net operating loss carryforward for which no benefit could be recognized under
  United's tax allocation policy..................................................     60,368
Other.............................................................................      4,009
                                                                                    ---------
                                                                                    $  48,177
                                                                                    ---------
                                                                                    ---------
</TABLE>
 
    As of December 31, 1995, EDI had no federal and state tax loss
carryforwards. Under a tax sharing agreement, tax loss carryforwards are not
available to EDI because United has already realized these tax benefits in its
prior years, consolidated federal and state returns.
 
3. EMPLOYEE STOCK OWNERSHIP PLAN
 
    EDI employees participate in United's unleveraged Employee Stock Ownership
Plan ("ESOP") maintained for the benefit of all eligible employees. United
contributions are made at the discretion of the Board of Directors.
Contributions totaling $3,700 for the year ended December 31, 1995, have been
made to the ESOP for EDI employees.
 
                                      F-38
<PAGE>
                               EDI SERVICES GROUP
                 (A DIVISION OF UNITED HEALTHCARE CORPORATION)
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
                      FOR THE YEAR ENDED DECEMBER 31, 1995
 
4. RELATED PARTIES
 
    Revenue from processing transactions and site licensing for United and its
affiliates comprises approximately 98% of total revenue for the year ended
December 31, 1995, and was approximately $4,056,000 for the year then ended.
 
    EDI utilizes various common corporate systems and support maintained by
United. The related costs are charged to EDI based on specific allocation
methods, if applicable, and are based on employee headcount. These functions
include human resources, accounting, legal, other processing and administrative
services, and building rent. The total amounts allocated to EDI were
approximately $438,000 for the year ended December 31, 1995. United's management
believes that these allocations are reasonable; however, these allocations would
not necessarily represent the amounts that would have been incurred on a
separate company basis.
 
5. SUBSEQUENT EVENTS
 
    On March 1, 1996, United and UHC Green (renamed "EDI Services, Inc.")
entered into an agreement with ActaMed and EDI Acquisition, Inc. (a
subcorporation of ActaMed). This agreement allows for the acquisition of EDI
Services, Inc. by ActaMed pursuant to the merger of EDI Acquisition, Inc. with
and into EDI Services, Inc. effective March 31, 1996. The outstanding shares of
capital stock of EDI Services, Inc. were converted into 10,344,828 shares of
ActaMed's Series C convertible redeemable preferred stock.
 
                                      F-39
<PAGE>
                                [HEALTHEON LOGO]
<PAGE>
                 [ALTERNATE PAGE FOR INTERNATIONAL PROSPECTUS]
 
PROSPECTUS
 
                                5,000,000 SHARES
 
                                 [HEALTHEON LOGO]
 
                                  COMMON STOCK
 
                               -----------------
 
   HEALTHEON CORPORATION IS OFFERING SHARES OF ITS COMMON STOCK. THIS IS OUR
 INITIAL PUBLIC OFFERING AND NO PUBLIC MARKET CURRENTLY EXISTS FOR OUR SHARES.
  WE HAVE REQUESTED THAT THE UNDERWRITERS RESERVE UP TO 837,500 SHARES TO BE
        OFFERED TO THE PERSONS IDENTIFIED ON PAGE 76 OF THE PROSPECTUS.
 
                              -------------------
 
   OUR COMMON STOCK IS LISTED ON THE NASDAQ NATIONAL MARKET UNDER THE SYMBOL
                                    "HLTH."
 
                              -------------------
 
                 INVESTING IN THE COMMON STOCK INVOLVES RISKS.
                    SEE "RISK FACTORS" BEGINNING ON PAGE 5.
 
                               -----------------
 
                                PRICE $8 A SHARE
                               -----------------
 
<TABLE>
<CAPTION>
                                                               UNDERWRITING
                                                PRICE TO      DISCOUNTS AND     PROCEEDS TO
                                                 PUBLIC        COMMISSIONS        COMPANY
                                             ---------------  --------------  ---------------
<S>                                          <C>              <C>             <C>
PER SHARE..................................       $8.00            $.56            $7.44
TOTAL......................................  $    40,000,000  $    2,800,000  $    37,200,000
</TABLE>
 
THE SECURITIES AND EXCHANGE COMMISSION AND STATE SECURITIES REGULATORS HAVE NOT
APPROVED OR DISAPPROVED THESE SECURITIES, OR DETERMINED IF THIS PROSPECTUS IS
TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.
 
HEALTHEON HAS GRANTED THE UNDERWRITERS THE RIGHT TO PURCHASE UP TO AN ADDITIONAL
750,000 SHARES OF COMMON STOCK TO COVER OVER-ALLOTMENTS. MORGAN STANLEY & CO.
INCORPORATED EXPECTS TO DELIVER THE SHARES TO PURCHASERS ON FEBRUARY 17, 1999.
 
                              -------------------
 
MORGAN STANLEY DEAN WITTER                          GOLDMAN, SACHS INTERNATIONAL
 
HAMBRECHT & QUIST                                   VOLPE BROWN WHELAN & COMPANY
 
FEBRUARY 10, 1999


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