F5 NETWORKS INC
424B1, 1999-09-30
COMPUTER INTEGRATED SYSTEMS DESIGN
Previous: F5 NETWORKS INC, S-1MEF, 1999-09-30
Next: AVANI INTERNATIONAL GROUP INC //, 8-K, 1999-09-30



<PAGE>
                                                FILED PURSUANT TO RULE 424(b)(1)
                                                      REGISTRATION NO. 333-86767

PROSPECTUS

                                2,200,000 SHARES

                                     [LOGO]

                                  COMMON STOCK

    This is an offering of common stock by F5 Networks, Inc. Of the 2,200,000
shares of common stock being sold in this offering, 500,000 shares are being
sold by F5 and 1,700,000 shares are being sold by the selling shareholders. F5
will not receive any of the proceeds from the sale of shares by the selling
shareholders. Our common stock trades on the Nasdaq National Market under the
symbol FFIV. On September 29, 1999, the last reported sale price of our common
stock on the Nasdaq National Market was $67.50 per share. See "Market Price of
the Common Stock."

                                 --------------

<TABLE>
<CAPTION>
                                                                      PER SHARE      TOTAL
                                                                     -----------  -----------
<S>                                                                  <C>          <C>
Public offering price..............................................   $   67.00   $147,400,000
Underwriting discounts and commissions.............................   $    3.35   $ 7,370,000
Proceeds to F5, before expenses....................................   $   63.65   $31,825,000
Proceeds to the selling shareholders, before expenses..............   $   63.65   $108,205,000
</TABLE>

    Certain shareholders have granted the underwriters an option for a period of
30 days to purchase up to 330,000 additional shares of common stock.

                                 --------------

    INVESTING IN THE COMMON STOCK INVOLVES A HIGH DEGREE OF RISK. SEE "RISK
FACTORS" BEGINNING ON PAGE 7.

                                 -------------

    NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR PASSED UPON THE
ADEQUACY OR ACCURACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

HAMBRECHT & QUIST
           BANCBOSTON ROBERTSON STEPHENS
                       BEAR, STEARNS & CO. INC.
                                   DAIN RAUSCHER WESSELS     A DIVISION OF DAIN
RAUSCHER INCORPORATED

September 30, 1999
<PAGE>

EDGAR Artwork Descriptions

Inside Front Cover of Prospectus:

    Caption 1:
    Internet Quality Control

    Caption 2:
    Availability
    Performance
    Manageability

    Graphic depicting F5 Networks logo surrounded by names and logos
    of its current products and product under development:

        Upper left hand quadrant caption:
        BIG/ip logo and name

        Upper right hand quadrant caption:
        3DNS logo and name

        Lower left hand quadrant caption:
        Global/SITE logo with caption "under development" underneath

        Lower right hand quadrant caption:
        see/IT logo and name

    F5 Networks logo

Inside Gatefold:

Upper left hand corner:

    F5 Networks logo

    Title: Availability, performance and control for mission-critical
    Internet sites

    Graphic depicting the role of the BIG/ip Controller, 3DNS Controller, see/IT
    Network Manager and global/SITE Controller in an organization's
    Internet-based environment. In the graphic, an organization's Internet and
    file servers are shown in multiple locations (Seattle, New York, London and
    Tokyo) with the F5 products placed between the Internet servers and the
    organization's routers. Dashed lines illustrate the interaction of the F5
    products within the organization's network.

    Caption 1 - upper left hand corner:
       BIG/ip Controller name and logo
       An intelligent load balancer for local area networks

    Caption 2 - upper right hand corner
       3DNS Controller name and logo
       An intelligent load balancer for wide area networks

    Caption 3 - lower right hand corner
       See/IT Network Manager name and logo
       A traffic analysis and network management software application for
       BIG/ip and 3DNS

    Caption 4 - lower left hand corner:
       Global/SITE Controller name and logo with caption "Under Development"
       underneath
       File replication and synchronization controller for managing content
       across geographically dispersed Internet sites

Inside Back Cover:

    F5 Networks logo with the following words underneath:

    F5 Networks, Inc. provides integrated Internet traffic management solutions
    designed to improve the availability and performance of mission-critical
    Internet-based servers and applications
<PAGE>
                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                    PAGE
                                                    ----
<S>                                                 <C>
Prospectus Summary................................    4

Risk Factors......................................    7

Forward Looking Statements........................   13

Use of Proceeds...................................   14

Dividend Policy...................................   14

Market Price of the Common Stock..................   14

Capitalization....................................   15

Selected Financial Data...........................   16

Management's Discussion and Analysis of Financial
  Condition and Results of Operations.............   17

Business..........................................   26

Management........................................   37

Certain Transactions..............................   46

Principal and Selling Shareholders................   48

Description of Capital Stock......................   50

Shares Eligible for Future Sale...................   53

Underwriting......................................   55

Legal Matters.....................................   56

Experts...........................................   56

Additional F5 Information.........................   56

Index to Financial Statements.....................  F-1
</TABLE>

    Information contained on F5's Web site does not constitute part of this
prospectus.

    BIG/ip-Registered Trademark-, the F5 logo, and 3DNS-Registered Trademark-
are registered United States trademarks of F5. This prospectus also contains
trademarks and tradenames of other companies.

                                       3
<PAGE>
                               PROSPECTUS SUMMARY

    THIS SUMMARY HIGHLIGHTS SELECTED INFORMATION CONTAINED ELSEWHERE IN THIS
PROSPECTUS. THIS SUMMARY MAY NOT CONTAIN ALL OF THE INFORMATION THAT YOU SHOULD
CONSIDER BEFORE INVESTING IN OUR COMMON STOCK. YOU SHOULD READ THE ENTIRE
PROSPECTUS CAREFULLY, INCLUDING "RISK FACTORS" AND THE FINANCIAL STATEMENTS,
BEFORE MAKING AN INVESTMENT DECISION.

                                  F5 NETWORKS

    F5 is a leading provider of integrated Internet traffic management solutions
designed to improve the availability and performance of mission-critical
Internet-based servers and applications. Our products monitor and manage local
and geographically dispersed servers and intelligently direct traffic to the
server best able to handle a user's request. Our products are designed to help
prevent system failure and provide timely responses to user requests and data
flow. Our BIG/ip-Registered Trademark- and 3DNS-Registered Trademark-
Controllers, when combined with our see/IT-TM- Network Manager, help
organizations optimize their network server availability and performance and
cost-effectively manage their Internet infrastructure. Our solutions are used by
organizations who rely on the Internet as a fundamental component of their
business. Our customers include Internet service providers, such as Exodus
Communications, Frontier GlobalCenter, PSINet, and MCI WorldCom, e-commerce
companies and many other organizations that employ high-traffic Internet sites.
We have sold our products to over 600 end-customers as of August 31, 1999.

    The Internet has emerged as a critical commerce and communications platform
for businesses and consumers worldwide. The growing use of the Internet is
causing the complexity and volume of Internet traffic to increase dramatically.
According to UUNet estimates, Internet traffic doubles every 100 days. The
widespread proliferation in the use and importance of the Internet has strained
many organizations' network infrastructures. In response to dramatic increases
in Internet use and traffic, organizations are expanding server capacity and are
deploying redundant servers. According to IBM, servers are being connected to
the Internet at a rate of 53,000 per month. While additional and redundant
servers help address the rapidly increasing traffic, they also increase an
organization's need for sophisticated Internet traffic management tools to
manage the availability and performance of its servers and applications.

    We believe that our products deliver Internet quality control by providing
the following key benefits:

    - HIGH SYSTEM AVAILABILITY. Our products help prevent system failure by
      quickly detecting server, application and network failures and directing
      traffic to functioning servers and applications.

    - INCREASED PERFORMANCE. Our products intelligently direct user requests to
      the server with the fastest response time by monitoring server and
      application response time and verifying content.

    - COST-EFFECTIVE SCALABILITY. Our products help optimize existing server
      capacity and allow the transparent addition of servers into an existing
      network.

    - EASIER NETWORK MANAGEABILITY. Our products collect information that can be
      used to facilitate network management and planning from a central
      location.

    - ENHANCED NETWORK CONTROL. Our products enable organizations to prioritize
      and manage network traffic based on user-defined criteria to meet their
      specific needs.

    We plan to continue expanding our suite of products to provide complete,
integrated Internet traffic management solutions that further optimize the
availability and performance of network servers and applications. For example,
we are currently developing our global/SITE-TM- Controller to ensure data
integrity by automatically synchronizing content across local and geographically
dispersed network servers. We also plan to continue investing significant
resources to expand our direct sales force and further develop our indirect
sales channels through leading industry resellers, original equipment
manufacturers, systems integrators, Internet service providers and other channel
partners. Finally, we intend to continue investing in our professional services
group in order to provide the installation, training and support services
required to help our customers optimize their use of our Internet traffic
management solutions.

    Our headquarters are located at 200 First Avenue West, Suite 500, Seattle,
Washington 98119, our telephone number is (206) 505-0800 and our Web site
address is www.F5.com.

                                       4
<PAGE>
                                  THE OFFERING

<TABLE>
<S>                                 <C>
Common stock offered by F5........  500,000 shares

Common stock offered by the
  selling shareholders............  1,700,000 shares

Common stock to be outstanding
  after this offering.............  18,626,667 shares (1)

Use of proceeds...................  For working capital and general corporate purposes. See
                                    "Use of Proceeds."

Nasdaq National Market symbol.....  FFIV
</TABLE>

- ------------------------

(1) The number of shares of common stock to be outstanding after this offering
    is based on the number of shares outstanding as of August 31, 1999 and does
    not include the following:

    - 2,440,405 shares subject to options outstanding as of August 31, 1999 with
      a weighted average exercise price of $3.75 per share;

    - 2,740,554 additional shares that could be issued under our stock option
      plans and stock purchase plan; and

    - 2,212,500 shares that could be issued upon exercise of warrants
      outstanding as of August 31, 1999 with a weighted average exercise price
      of $0.75 per share.

                                 --------------

    ALL INFORMATION IN THIS PROSPECTUS RELATING TO OUTSTANDING SHARES OF F5
COMMON STOCK AND OPTIONS OR WARRANTS TO PURCHASE F5 COMMON STOCK IS BASED UPON
INFORMATION AS OF AUGUST 31, 1999. UNLESS OTHERWISE INDICATED, THE INFORMATION
THROUGHOUT THIS PROSPECTUS DOES NOT TAKE INTO ACCOUNT THE POSSIBLE ISSUANCE OF
ADDITIONAL SHARES OF COMMON STOCK TO THE UNDERWRITERS PURSUANT TO THEIR
OVER-ALLOTMENT OPTION.

    PLEASE SEE "CAPITALIZATION" FOR A MORE COMPLETE DISCUSSION REGARDING THE
OUTSTANDING SHARES OF F5 COMMON STOCK AND OPTIONS OR WARRANTS TO PURCHASE F5
COMMON STOCK AND OTHER RELATED MATTERS.

                                       5
<PAGE>
                         SUMMARY FINANCIAL INFORMATION
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)

<TABLE>
<CAPTION>
                                                                           FISCAL YEAR ENDED    NINE MONTHS ENDED JUNE
                                                  PERIOD FROM FEBRUARY       SEPTEMBER 30,               30,
                                                 26, 1996 (INCEPTION) TO  --------------------  ----------------------
                                                   SEPTEMBER 30, 1996       1997       1998                    1999
                                                 -----------------------  ---------  ---------     1998      ---------
                                                                                                -----------
                                                                                                (UNAUDITED)
<S>                                              <C>                      <C>        <C>        <C>          <C>
STATEMENT OF OPERATIONS DATA:
  Net revenues.................................         $       2         $     229  $   4,889   $   2,981   $  14,062
  Loss from operations.........................              (348)           (1,428)    (3,668)     (2,277)     (6,864)
  Net loss.....................................         $    (330)        $  (1,456) $  (3,672)  $  (2,298)  $  (6,678)
  Net loss per share--basic and diluted........         $   (0.06)        $   (0.24) $   (0.60)  $   (0.37)  $   (0.88)
  Weighted average shares--basic and diluted
    (1)........................................             5,932             6,000      6,086       6,135       7,582
  Pro forma net loss per share (unaudited):
    Net loss per share--basic and diluted......                                      $   (0.26)              $   (0.45)
                                                                                     ---------               ---------
                                                                                     ---------               ---------
    Weighted average shares--basic and diluted
      (1)......................................                                         14,201                  14,923
                                                                                     ---------               ---------
                                                                                     ---------               ---------
</TABLE>

<TABLE>
<CAPTION>
                                                                           JUNE 30, 1999
                                                                     --------------------------
                                                                      ACTUAL    AS ADJUSTED (2)
                                                                     ---------  ---------------
<S>                                                                  <C>        <C>
BALANCE SHEET DATA:
  Cash and cash equivalents........................................  $  26,948     $  58,423
  Working capital..................................................     26,774        58,249
  Total assets.....................................................     36,486        67,961
  Shareholders' equity.............................................     28,905        60,380
</TABLE>

- ------------------------

(1) See Note 2 of notes to financial statements for an explanation of the
    determination of the number of shares used in computing per share data.

(2) Adjusted to reflect the sale by F5 of 500,000 shares of common stock at the
    public offering price of $67.00 per share and the application of the
    estimated net proceeds after deducting underwriting discounts and
    commissions and our estimated offering expenses. See "Use of Proceeds" and
    "Capitalization."

                                       6
<PAGE>
                                  RISK FACTORS

    YOU SHOULD CAREFULLY CONSIDER THE FOLLOWING RISK FACTORS AND ALL OTHER
INFORMATION CONTAINED IN THIS PROSPECTUS BEFORE PURCHASING OUR COMMON STOCK.
INVESTING IN OUR COMMON STOCK INVOLVES A HIGH DEGREE OF RISK. ANY OF THE
FOLLOWING RISKS MAY SERIOUSLY HARM OUR BUSINESS AND RESULTS OF OPERATIONS AND
MAY RESULT IN A COMPLETE LOSS OF YOUR INVESTMENT.

OUR LIMITED OPERATING HISTORY MAKES IT DIFFICULT TO EVALUATE OUR PROSPECTS.

    We were founded in February 1996 and have a limited operating history, which
makes an evaluation of our prospects difficult. Because of our limited operating
history, we have limited insight into trends that may emerge and affect our
business. In addition, the revenues and income potential of our business and
market are unproven. An investor in our common stock must consider the
challenges, expenses and difficulties we face as an early stage company in a new
and rapidly evolving market.

OUR QUARTERLY OPERATING RESULTS ARE VOLATILE AND MAY CAUSE OUR STOCK PRICE TO
  FLUCTUATE.

    Our quarterly operating results have varied significantly in the past and
will vary significantly in the future, which makes it difficult for us to
predict our future operating results. In particular, we anticipate that the size
of customer orders may increase as we continue to focus on larger business
accounts and sales to governmental entities. A delay in the recognition of
revenue, even from just one account, may have a significant negative impact on
our results of operations for a given period. In the past, a significant portion
of our sales have been realized near the end of a quarter. Accordingly, a delay
in an anticipated sale past the end of a particular quarter may negatively
impact our results of operations for that quarter. Furthermore, we base our
decisions regarding our operating expenses on anticipated revenue trends, and
our expense levels are relatively fixed. Consequently, if revenue levels fall
below our expectations, our net income (loss) will decrease (increase) because
only a small portion of our expenses vary with our revenues. See "Management's
Discussion and Analysis of Financial Condition and Results of Operations."

    We believe that period-to-period comparisons of our results of operations
are not meaningful and should not be relied upon as indicators of future
performance. Our operating results will likely be below the expectations of
securities analysts and investors in some future quarter or quarters. Our
failure to meet these expectations will likely seriously harm the market price
of our common stock.

WE HAVE INCURRED LOSSES AND WE EXPECT TO INCUR SIGNIFICANT FUTURE OPERATING
  EXPENSES AND LOSSES.

    We have experienced operating losses in each quarterly and annual period
since inception. We incurred net losses of $330,000 for the period from February
26, 1996, inception, to September 30, 1996, $1.5 million for the year ended
September 30, 1997, $3.7 million for the year ended September 30, 1998, and $6.7
million for the nine months ended June 30, 1999.

    We intend to substantially increase our operating expenses. As a result, we
will need to generate significant increases in our quarterly net revenues to
achieve and maintain profitability. Although our net revenues have grown in
recent quarters, we may not be able to sustain these growth rates or achieve or
sustain profitability. Our failure to achieve and sustain profitability will
seriously harm our business and results of operations. See "Selected Financial
Data" and "Management's Discussion and Analysis of Financial Condition and
Results of Operations."

OUR SUCCESS DEPENDS ON SALES OF OUR BIG/IP-REGISTERED TRADEMARK- CONTROLLER.

    We currently derive approximately 73% of our net revenues from sales of our
BIG/ip Controller. In addition, we expect to derive a significant portion of our
net revenues from sales of BIG/ip in the future. Implementation of our strategy
depends upon BIG/ip being able to solve critical network availability and

                                       7
<PAGE>
performance problems of our customers. If BIG/ip is unable to solve these
problems for our customers, our business and results of operations will be
seriously harmed.

OUR SUCCESS DEPENDS ON OUR TIMELY DEVELOPMENT OF NEW PRODUCTS AND FEATURES.

    We expect the Internet traffic management market to be characterized by
rapid technological change, frequent new product introductions, changes in
customer requirements and evolving industry standards. We are currently
developing our global/SITE-TM- Controller and new features for our existing
products. We expect to continue to develop new products and new product features
in the future. If we fail to develop and deploy new products and new product
features on a timely basis, our business and results of operations may be
seriously harmed. See "Business--Product Development."

WE MAY NOT BE ABLE TO COMPETE EFFECTIVELY IN THE EMERGING INTERNET TRAFFIC
  MANAGEMENT MARKET.

    Our markets are new, rapidly evolving and highly competitive, and we expect
competition to persist and intensify in the future. Our principal competitors in
the Internet traffic management market include Cisco Systems, Alteon WebSystems,
ArrowPoint Communications, HydraWeb Technologies, RadWare and Resonate. We
expect to continue to face additional competition as new participants enter the
Internet traffic management market. In addition, larger companies with
significant resources, brand recognition and sales channels may form alliances
with or acquire competing Internet traffic management solutions and emerge as
significant competitors. Potential competitors may bundle their products or
incorporate an Internet traffic management component into existing products in a
manner that discourages users from purchasing our products. Potential customers
may also choose to purchase additional servers instead of our products. See
"Business--Competition."

WE MAY NOT BE ABLE TO SUPPORT OUR RAPID GROWTH EFFECTIVELY.

    Since the introduction of our product line, we have experienced a period of
rapid growth and expansion which has placed, and continues to place, a
significant strain on all of our resources. From September 30, 1997 to August
31, 1999, we increased the number of our employees from 20 to 178. We expect our
growth to continue to strain our management, operational and financial
resources. For example, we may not be able to install adequate financial control
systems in an efficient and timely manner, and our current or planned
information systems, procedures and controls may be inadequate to support our
future operations. The difficulties associated with installing and implementing
new systems, procedures and controls may place a significant burden on our
management and our internal resources. Our inability to manage growth
effectively may seriously harm our business and results of operations.

OUR EXPANSION INTO INTERNATIONAL MARKETS MAY NOT SUCCEED.

    We intend to expand into international markets. We have only limited
experience in marketing, selling and supporting our products internationally.
International sales represented 6.6% of our net revenues for the year ended
September 30, 1997, 3.5% for the year ended September 30, 1998 and 7.1% for the
nine months ended June 30, 1999. We have recently engaged sales personnel in the
United Kingdom and in Germany. Our continued growth will require further
expansion of our international operations in selected countries in the European
and Asia Pacific markets. If we are unable to expand our international
operations successfully and in a timely manner, our business and results of
operations may be seriously harmed. Such expansion may be more difficult or take
longer than we anticipate, and we may not be able to successfully market, sell,
deliver and support our products internationally.

WE MAY NOT BE ABLE TO SUSTAIN OR DEVELOP NEW DISTRIBUTION RELATIONSHIPS.

    Our sales strategy requires that we establish multiple distribution channels
in the United States and internationally through leading industry resellers,
original equipment manufacturers, systems integrators,

                                       8
<PAGE>
Internet service providers and other channel partners. We have a limited number
of agreements with companies in these channels, and we may not be able to
increase our number of distribution relationships or maintain our existing
relationships. One of our resellers, Exodus Communications, Inc., accounted for
21.7% of our net revenues for the nine months ended June 30, 1999 and 29.4% of
our accounts receivable balance at June 30, 1999. Our inability to effectively
establish our indirect sales channels will seriously harm our business and
results of operations.

OUR SUCCESS DEPENDS ON OUR ABILITY TO ATTRACT, TRAIN AND RETAIN QUALIFIED
  MARKETING AND SALES, PROFESSIONAL SERVICES AND CUSTOMER SUPPORT PERSONNEL.

    Our products require a sophisticated marketing and sales effort targeted at
several levels within a prospective customer's organization. We have recently
expanded our sales force and plan to hire additional sales personnel for direct
sales and to develop leads for our indirect sales channels. Competition for
qualified sales personnel is intense, and we might not be able to hire the kind
and number of sales personnel we are targeting. Our inability to retain and hire
qualified sales personnel may seriously harm our business and results of
operations.

    We currently have a small professional services and customer support
organization and will need to increase our staff to support new customers and
the expanding needs of existing customers. The installation of Internet traffic
management solutions, the integration of these solutions into existing networks
and the ongoing support can be complex. Accordingly, we need highly-trained
professional services and customer support personnel. Hiring professional
services and customer support personnel is very competitive in our industry due
to the limited number of people available with the necessary technical skills
and understanding of our products. Our inability to attract, train or retain the
number of highly qualified professional services and customer support personnel
that our business needs may seriously harm our business and results of
operations.

WE DEPEND ON OUR KEY PERSONNEL AND THE LOSS OF ANY KEY PERSONNEL MAY HARM OUR
  BUSINESS AND RESULTS OF OPERATIONS.

    Our success depends to a significant degree upon the continued contributions
of our key management, product development, sales and marketing and finance
personnel, many of whom will be difficult to replace. In particular, we rely on
our President and Chief Executive Officer, Jeffrey Hussey. The loss of services
of any of our key personnel, especially the services of Mr. Hussey, may
seriously harm our business and results of operations. We do not have employment
contracts with any of our key personnel.

IT IS DIFFICULT TO PREDICT OUR FUTURE OPERATING RESULTS BECAUSE WE HAVE AN
  UNPREDICTABLE SALES CYCLE.

    We are unable to predict our sales cycle because we have limited experience
selling our products. Historically, our sales cycle has ranged from
approximately two to three months. Sales of BIG/ip, 3DNS and our see/IT-TM-
Network Manager require us to educate potential customers on their use and
benefits. The sale of our products is subject to delays from the lengthy
internal budgeting, approval and competitive evaluation processes that large
corporations and governmental entities may require. For example, customers
frequently begin by evaluating our products on a limited basis and devote time
and resources to testing our products before they decide whether or not to
purchase. Customers may also defer orders as a result of anticipated releases of
new products or enhancements by us or our competitors. As a result, our products
have an unpredictable sales cycle that contributes to the uncertainty of our
future operating results.

                                       9
<PAGE>
THE AVERAGE SELLING PRICES OF OUR PRODUCTS MAY DECREASE, WHICH MAY NEGATIVELY
  IMPACT GROSS PROFITS.

    We anticipate that the average selling prices of our products will decrease
in the future in response to competitive pricing pressures, increased sales
discounts, new product introductions by us or our competitors or other factors.
Therefore, in order to maintain our gross profits, we must develop and introduce
new products and product enhancements on a timely basis and continually reduce
our product costs. Our failure to do so will cause our net revenue and gross
profits to decline, which will seriously harm our business and results of
operations. In addition, we may experience substantial period-to-period
fluctuations in future operating results due to the erosion of our average
selling prices.

OUR BUSINESS MAY BE HARMED IF OUR CONTRACT MANUFACTURERS ARE NOT ABLE TO PROVIDE
  US WITH ADEQUATE SUPPLIES OF OUR PRODUCTS.

    We rely on third party contract manufacturers to assemble our products. We
outsource the manufacturing of our pre-configured, industry-standard hardware
platforms to primarily two contract manufacturers, Micro Standard Distributors
and Unisoft, who assemble these hardware platforms to our specifications. The
inability of our contract manufacturers to provide us with adequate supplies of
our products or the loss of one or more of our contract manufacturers may cause
a delay in our ability to fulfill orders while we obtain a replacement
manufacturer and may seriously harm our business and results of operations.

    If the demand for our products grows, we will need to increase our material
purchases, contract manufacturing capacity and internal test and quality
functions. Any disruptions in product flow may limit our revenue, may seriously
harm our competitive position and may result in additional costs or cancellation
of orders by our customers. See "Business--Manufacturing."

OUR BUSINESS COULD SUFFER IF THERE ARE ANY INTERRUPTIONS OR DELAYS IN THE SUPPLY
  OF HARDWARE COMPONENTS FROM OUR THIRD-PARTY SOURCES.

    We currently purchase several hardware components used in the assembly of
our products from limited sources. Lead times for these components vary
significantly. Any interruption or delay in the supply of any of these hardware
components, or the inability to procure a similar component from alternate
sources at acceptable prices within a reasonable time, will seriously harm our
business and results of operations. See "Business--Manufacturing."

UNDETECTED SOFTWARE ERRORS MAY SERIOUSLY HARM OUR BUSINESS AND RESULTS OF
  OPERATIONS.

    Software products frequently contain undetected errors when first introduced
or as new versions are released. We have experienced these errors in the past in
connection with new products and product upgrades. We expect that these errors
will be found from time to time in new or enhanced products after commencement
of commercial shipments. These problems may cause us to incur significant
warranty and repair costs, divert the attention of our engineering personnel
from our product development efforts and cause significant customer relations
problems. We may also be subject to liability claims for damages related to
product errors. While we carry insurance policies covering this type of
liability, these policies may not provide sufficient protection should a claim
be asserted. A material product liability claim may seriously harm our business
and results of operations.

    Our products must successfully operate with products from other vendors. As
a result, when problems occur in a network, it may be difficult to identify the
source of the problem. The occurrence of software errors, whether caused by our
products or another vendor's products, may result in the delay or loss of market
acceptance of our products. The occurrence of any of these problems may
seriously harm our business and results of operations.

                                       10
<PAGE>
WE MAY NOT ADEQUATELY PROTECT OUR INTELLECTUAL PROPERTY AND OUR PRODUCTS MAY
  INFRINGE ON THE INTELLECTUAL PROPERTY RIGHTS OF THIRD PARTIES.

    We rely on a combination of copyright, trademark and trade secret laws and
restrictions on disclosure to protect our intellectual property rights. Despite
our efforts to protect our proprietary rights, unauthorized parties may attempt
to copy or otherwise obtain and use our products or technology. Monitoring
unauthorized use of our products is difficult, and we cannot be certain that the
steps we have taken will prevent misappropriation of our technology,
particularly in foreign countries where the laws may not protect our proprietary
rights as fully as in the United States. In addition, we have not entered into
non-competition agreements with several of our former employees.

    From time to time, third parties may assert patent, copyright, trademark and
other intellectual property rights claims or initiate litigation against us or
our contract manufacturers, suppliers or customers with respect to existing or
future products. In the event of a successful claim of infringement and our
failure or inability to develop non-infringing technology or license the
infringed or similar technology on a timely basis, our business and results of
operations may be seriously harmed. See "Business--Intellectual Property."

OUR FAILURE AND THE FAILURE OF OUR KEY SUPPLIERS, MANUFACTURERS AND CUSTOMERS TO
  BE YEAR 2000 COMPLIANT MAY NEGATIVELY IMPACT OUR BUSINESS AND RESULTS OF
  OPERATIONS.

    The Year 2000 computer issue creates a significant risk for us in at least
four areas:

    - potential warranty or other claims arising from our products;

    - systems we use to run our business;

    - systems used by our suppliers and contract manufacturers; and

    - the potential reduced spending by other companies on Internet traffic
      management solutions as a result of significant information systems
      spending on Year 2000 remediation or to limit additional changes to their
      systems during the current year.

    A failure in any of these areas to be Year 2000 compliant may seriously harm
our operations. See "Management's Discussion and Analysis of Financial Condition
and Results of Operations--Year 2000 Compliance."

LAWS RELATING TO ENCRYPTED SOFTWARE MAY LIMIT THE MARKETABILITY OF OUR PRODUCTS.

    The encryption technology contained in our products is subject to United
States export controls. These export controls limit our ability to distribute
encrypted software outside of the United States and Canada. While we take
precautions against unlawful exportation, this exportation inadvertently may
have occurred in the past or may occur from time to time in the future,
subjecting us to potential liability and serious harm. We may also encounter
difficulties competing with non-United States producers of products containing
encrypted software, who may both import their products into the United States
and sell products overseas.

WE MAY NEED TO RAISE ADDITIONAL FUNDS, WHICH MAY NOT BE AVAILABLE.

    We expect that the net proceeds from this offering, our existing cash
balances and cash from operations will be sufficient to meet our currently
anticipated working capital and capital expenditure needs for the foreseeable
future. If currently unforeseen events arise, such as a product or technology
acquisition paid for with cash, we may need to raise additional funds, and
additional financing may not be available on favorable terms, if at all.
Further, if we issue additional equity securities, shareholders may experience
dilution, and the new equity securities may have rights, preferences or
privileges senior to those of existing holders of our common stock. If we cannot
raise funds, if needed, on acceptable terms,

                                       11
<PAGE>
we may not be able to develop new products or enhance our existing products,
take advantage of future opportunities or respond to competitive pressures or
unanticipated requirements. This may seriously harm our business and results of
operations. See "Use of Proceeds," "Dilution" and "Management's Discussion and
Analysis of Financial Condition and Results of Operations--Liquidity and Capital
Resources."

OUR EXISTING SHAREHOLDERS WILL BE ABLE TO EXERCISE SIGNIFICANT CONTROL OVER ALL
  MATTERS REQUIRING SHAREHOLDER APPROVAL.

    On completion of this offering, executive officers, directors and their
affiliates and 5% shareholders will beneficially own, in the aggregate,
approximately 59.4% of our outstanding common stock. As a result, these
shareholders will be able to exercise significant control over all matters
requiring shareholder approval, including the election of directors and approval
of significant corporate transactions, which may have the effect of delaying or
preventing a third party from acquiring control over us. See "Principal and
Selling Shareholders."

WE ARE AT RISK OF SECURITIES CLASS ACTION LITIGATION DUE TO OUR EXPECTED STOCK
  PRICE VOLATILITY.

    An active public market price for our common stock may not be maintained in
the future. The market price of our common stock has fluctuated and may continue
to fluctuate significantly in response to a number of factors, some of which are
beyond our control. See "Market Price of the Common Stock." In the past,
securities class action litigation has often been brought against a company
following periods of volatility in the market price of its securities. We may in
the future be the target of similar litigation. Securities litigation may result
in substantial costs and divert management's attention and resources, which may
seriously harm our business and results of operations.

WE HAVE IMPLEMENTED ANTI-TAKEOVER PROVISIONS THAT COULD DELAY OR PREVENT A
  CHANGE IN CONTROL OF F5.

    Provisions of our articles of incorporation and bylaws, as well as
provisions of Washington law, may make it more difficult for a third party to
acquire us, even if doing so would be beneficial to our shareholders. See
"Description of Capital Stock."

SUBSTANTIAL SALES OF SHARES MAY IMPACT THE MARKET PRICE OF OUR COMMON STOCK.

    If our shareholders sell substantial amounts of our common stock, including
shares issued upon the exercise of outstanding options and warrants, the market
price of our common stock may fall. Such sales might also make it more difficult
for us to sell equity or equity-related securities in the future at a time and
price that we deem appropriate. After completion of this offering, we will have
outstanding 18,626,667 shares of common stock, assuming no exercise of
outstanding options or warrants after August 31, 1999. See "Shares Eligible for
Future Sale" and "Underwriting."

WE MAY SPEND THE OFFERING PROCEEDS IN WAYS WITH WHICH OUR SHAREHOLDERS MAY NOT
  AGREE.

    The majority of the net proceeds to the Company of this offering are not
allocated for specific uses and our management can spend most of the proceeds
from this offering in ways with which our shareholders may not agree. We cannot
predict that the proceeds will be invested to yield a favorable return. See "Use
of Proceeds."

                                       12
<PAGE>
                           FORWARD LOOKING STATEMENTS

    Certain statements under the captions "Prospectus Summary," "Risk Factors,"
"Use of Proceeds," "Management's Discussion and Analysis of Financial Condition
and Results of Operations" and "Business," and elsewhere in this prospectus are
"forward-looking statements." These forward-looking statements include, but are
not limited to, statements about our plans, objectives, expectations and
intentions and other statements contained in the prospectus that are not
historical facts. When used in this prospectus, the words "expects,"
"anticipates," "intends," "plans," "believes," "seeks," "estimates" and similar
expressions are generally intended to identify forward-looking statements.
Because these forward-looking statements involve risks and uncertainties, there
are important factors that could cause actual results to differ materially from
those expressed or implied by these forward-looking statements, including our
plans, objectives, expectations and intentions and other factors discussed under
"Risk Factors."

                                       13
<PAGE>
                                USE OF PROCEEDS

    We will receive net proceeds of $31,475,000 from the sale of 500,000 shares
of common stock, at the public offering price of $67.00 per share after
deducting underwriting commissions and discounts of $1,675,000 and estimated
expenses of $350,000. We will not receive any proceeds from the sale of common
stock by the selling shareholders.

    We intend to use the proceeds of this offering for working capital and
general corporate purposes, including increased expenditures for sales and
marketing, research and development and professional services and technical
support. We may also use some of the proceeds for strategic acquisitions of
products and technologies that will complement or extend our existing Internet
traffic management solutions, although we are not currently planning any of
these transactions. Pending these uses, we intend to invest the net proceeds of
this offering in investment grade interest-bearing securities. We will retain
broad discretion in the allocation and use of the net proceeds of this offering.
See "Risk Factors--We may spend the offering proceeds in ways with which our
shareholders may not agree."

                                DIVIDEND POLICY

    F5 has never declared or paid any cash dividends on shares of its common
stock. We intend to retain any future earnings for future growth and do not
anticipate paying any cash dividends in the foreseeable future.

                        MARKET PRICE OF THE COMMON STOCK

    Our common stock began trading on the Nasdaq Stock Market's National Market
System on June 4, 1999 under the symbol FFIV. Prior to that time, there had been
no market for our common stock. The table below sets forth the high and low sale
prices for our common stock for the periods indicated:

<TABLE>
<CAPTION>
1999                                                                                               HIGH        LOW
- -----------------------------------------------------------------------------------------------  ---------  ---------
<S>                                                                                              <C>        <C>
June 4 - June 30...............................................................................  $   45.13  $   10.13
July 1 - September 29..........................................................................  $   85.00  $   27.75
</TABLE>

    The last reported sale price of our common stock on September 29, 1999 was
$67.50.

                                       14
<PAGE>
                                 CAPITALIZATION

    The following table sets forth the capitalization of F5 as of June 30, 1999
(1) on an actual basis, and (2) on a pro forma basis as adjusted to reflect, our
receipt of the estimated net proceeds from the sale of 500,000 shares of common
stock offered by us at the public offering price of $67.00 per share.

    The capitalization information set forth in the table below is qualified by,
and should be read in conjunction with, the more detailed financial statements
and notes of F5 appearing elsewhere in this prospectus.

<TABLE>
<CAPTION>
                                                                                              JUNE 30, 1999
                                                                                         ------------------------
                                                                                          ACTUAL     AS ADJUSTED
                                                                                         ---------  -------------
                                                                                              (IN THOUSANDS)
<S>                                                                                      <C>        <C>
Shareholders' equity:
    Common stock: no par value, 100,000,000 shares authorized, 18,108,185 issued and
      outstanding, actual; 100,000,000 shares authorized, 18,608,185 issued and
      outstanding, as adjusted.........................................................  $  45,751    $  77,226
    Note receivable from shareholder...................................................       (750)        (750)
    Unearned compensation..............................................................     (3,960)      (3,960)
    Accumulated deficit................................................................    (12,136)     (12,136)
                                                                                         ---------  -------------
        Total shareholders' equity.....................................................  $  28,905    $  60,380
                                                                                         ---------  -------------
                                                                                         ---------  -------------
</TABLE>

- ------------------------

This capitalization table excludes the following shares:

    - 2,369,262 shares subject to options outstanding as of June 30, 1999 with a
      weighted average exercise price of $1.50 per share;

    - 2,730,179 additional shares that could be issued under our stock option
      plans and stock purchase plan as of June 30, 1999; and

    - 2,212,500 shares that could be issued upon exercise of warrants
      outstanding as of June 30, 1999 with a weighted average exercise price of
      $0.75 per share.

                                       15
<PAGE>
                            SELECTED FINANCIAL DATA

    The selected statement of operations data for the period February 26, 1996,
inception, to September 30, 1996, and for the years ended September 30, 1997 and
1998 and for the nine months ended June 30, 1999 and the balance sheet data at
September 30, 1997 and 1998 and June 30, 1999 are derived from the financial
statements of F5, which have been audited by PricewaterhouseCoopers LLP,
independent accountants, and included elsewhere in this prospectus. The balance
sheet data at September 30, 1996 has been derived from the financial statements
of F5 which has been audited by PricewaterhouseCoopers LLP. The financial data
for the period ended June 30, 1998 is unaudited, but has been prepared on a
basis consistent with the audited financial statements of F5 and the notes
thereto and include all adjustments (constituting only normal recurring
adjustments) which F5 considered necessary for a fair presentation of the
information. The results of operations for the nine months ended June 30, 1999
are not necessarily indicative of results to be expected for the year or for any
future periods. The data set forth below should be read in conjunction with
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" and the financial statements and the notes thereto included
elsewhere in this prospectus (in thousands, except per share data).

<TABLE>
<CAPTION>
                                                 PERIOD FROM       FISCAL YEAR ENDED       NINE MONTHS ENDED JUNE 30,
                                                FEB. 26, 1996        SEPTEMBER 30,
                                               (INCEPTION) TO     --------------------  --------------------------------
                                               SEPT. 30, 1996       1997       1998                           1999
                                             -------------------  ---------  ---------       1998        ---------------
                                                                                        ---------------
                                                                                          (UNAUDITED)
<S>                                          <C>                  <C>        <C>        <C>              <C>
STATEMENT OF OPERATIONS DATA:
Net revenues:
  Products.................................       $       2       $     229  $   4,119     $   2,537        $  11,872
  Services.................................              --              --        770           444            2,190
                                                     ------       ---------  ---------       -------          -------
Total net revenues.........................               2             229      4,889         2,981           14,062
                                                     ------       ---------  ---------       -------          -------
Cost of net revenues:
  Products.................................               1              71      1,091           694            3,085
  Services.................................              --              --        314           171              976
                                                     ------       ---------  ---------       -------          -------
Total cost of net revenues.................               1              71      1,405           865            4,061
                                                     ------       ---------  ---------       -------          -------
  Gross profit.............................               1             158      3,484         2,116           10,001
                                                     ------       ---------  ---------       -------          -------
Operating expenses:
  Sales and marketing......................              62             565      3,881         2,439            9,113
  Research and development.................             103             569      1,810         1,059            3,810
  General and administrative...............             180             383      1,041           690            2,145
  Amortization of unearned compensation....               4              69        420           205            1,797
                                                     ------       ---------  ---------       -------          -------
    Total operating expenses...............             349           1,586      7,152         4,393           16,865
                                                     ------       ---------  ---------       -------          -------
Loss from operations.......................            (348)         (1,428)    (3,668)       (2,277)          (6,864)
Interest income (expense), net.............              18             (28)        (4)          (21)             186
                                                     ------       ---------  ---------       -------          -------
Net loss...................................       $    (330)      $  (1,456) $  (3,672)    $  (2,298)       $  (6,678)
                                                     ------       ---------  ---------       -------          -------
                                                     ------       ---------  ---------       -------          -------
Net loss per share--basic and diluted......       $   (0.06)      $   (0.24) $   (0.60)    $   (0.37)       $   (0.88)
                                                     ------       ---------  ---------       -------          -------
                                                     ------       ---------  ---------       -------          -------
Weighted average shares--basic and
  diluted..................................           5,932           6,000      6,086         6,135            7,582
                                                     ------       ---------  ---------       -------          -------
                                                     ------       ---------  ---------       -------          -------
Pro forma net loss per share (unaudited):
  Net loss per share--basic and diluted....                                  $   (0.26)                     $   (0.45)
                                                                             ---------                        -------
                                                                             ---------                        -------
  Weighted average shares--basic and
    diluted................................                                     14,201                         14,923
                                                                             ---------                        -------
                                                                             ---------                        -------
</TABLE>

<TABLE>
<CAPTION>
                                                                        SEPTEMBER 30,              JUNE 30,
                                                             -----------------------------------  -----------
                                                                1996         1997        1998        1999
                                                                 ---          ---      ---------  -----------
<S>                                                          <C>          <C>          <C>        <C>
BALANCE SHEET DATA:
Cash and cash equivalents..................................   $     624    $     143   $   6,206   $  26,948
Working capital (deficit)..................................         617         (317)      6,763      26,774
Total assets...............................................         817          919       9,432      36,486
Long-term obligations......................................          29          216          --          --
Redeemable convertible preferred stock.....................          --           --       7,688          --
Shareholders' equity (deficit).............................         737         (231)        (80)     28,905
</TABLE>

                                       16
<PAGE>
                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                 FINANCIAL CONDITION AND RESULTS OF OPERATIONS

    THE FOLLOWING MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION
AND RESULTS OF OPERATIONS SHOULD BE READ IN CONJUNCTION WITH OUR FINANCIAL
STATEMENTS AND NOTES. OUR DISCUSSION CONTAINS FORWARD-LOOKING STATEMENTS BASED
UPON CURRENT EXPECTATIONS THAT INVOLVE RISKS AND UNCERTAINTIES, SUCH AS OUR
PLANS, OBJECTIVES, EXPECTATIONS AND INTENTIONS. OUR ACTUAL RESULTS AND THE
TIMING OF CERTAIN EVENTS COULD DIFFER MATERIALLY FROM THOSE ANTICIPATED IN THESE
FORWARD-LOOKING STATEMENTS AS A RESULT OF CERTAIN FACTORS, INCLUDING THOSE SET
FORTH UNDER "RISK FACTORS," "BUSINESS" AND ELSEWHERE IN THIS PROSPECTUS.

OVERVIEW

    F5 is a leading provider of integrated Internet traffic management solutions
designed to improve the availability and performance of mission-critical
Internet-based servers and applications. We were incorporated on February 26,
1996 and began operations in April 1996. During the period from February 26,
1996 through September 30, 1996, we were a development stage enterprise and had
no product revenues. Our operating activities during this period related
primarily to developing our initial product, recruiting personnel, building our
corporate infrastructure and raising capital.

    In July 1997, we released our first version of our
BIG/ip-Registered Trademark- Controller, and began to expand our operations. We
increased our investments in research and development, marketing programs,
domestic and international sales channels, customer support and services and our
general and administrative infrastructure. Since June 30, 1997, we have:

    - hired more than 150 employees;

    - hired sales representatives in eight domestic locations;

    - hired professional services and customer support personnel in eight
      domestic locations;

    - released several upgrades to BIG/ip;

    - released two new products, our 3DNS-Registered Trademark- Controller and
      our see/IT-TM- Network Manager;

    - engaged sales representatives in the European and Asia Pacific markets;
      and

    - established a distributor relationship with one international reseller.

    Our net revenues grew from $229,000 for the year ended September 30, 1997 to
$4.9 million for the year ended September 30, 1998, and were $14.1 million for
the nine months ended June 30, 1999. Currently, we derive approximately 73% of
our revenues from sales of BIG/ip. One of our resellers, Exodus Communications,
accounted for 21.7% of our net revenues for the nine months ended June 30, 1999
and 29.4% of our accounts receivable balance at June 30, 1999. In addition, we
expect to derive a significant portion of our net revenues from sales of BIG/ip
in the future.

    Net revenues derived from customers located outside of the United States
were $15,000 in 1997, $172,000 in 1998 and $1.0 million for the nine months
ended June 30, 1999. We plan to expand our international operations
significantly, particularly in selected countries in the European and Asia
Pacific markets, because we believe international markets represent a
significant growth opportunity. The expansion of our international operations
will be subject to a variety of risks that could significantly harm our business
and results of operations.

    Customers who purchase BIG/ip or 3DNS receive installation services and an
initial customer support contract, typically covering a 12-month period.
Customers may also purchase consulting services and renew their initial customer
support contract. As of June 30, 1999, approximately 80% of our customers have
renewed or indicated an intent to renew their initial customer support contract.
Based on our limited operating history, it is difficult to predict what our rate
of renewals will be in the future. We generally

                                       17
<PAGE>
combine the software license, installation, and customer support elements of our
products into a package with a single price. We allocate a portion of the sales
price to each element of the bundled package based on their respective fair
values when the individual elements are sold separately. Revenues from the
license of software are recognized when the product has been shipped and the
customer is obligated to pay for the product. Installation revenue is recognized
when the product has been installed at the customer's site. Revenues for
customer support are recognized on a straight-line basis over the service
contract term. Consulting services are customarily billed at fixed rates, plus
out-of-pocket expenses. Our ordinary payment terms to our customers are net 30
days, but we have extended payment terms beyond net 30 days to some customers.
Estimated sales returns are based on historical experience by product and are
recorded at the time revenues are recognized.

    We have incurred losses since our inception, and as of June 30, 1999, had an
accumulated deficit of $12.1 million. Our success in growing net revenues
depends on increasing our customer base and expanding our product line as well
as continued growth of the emerging Internet traffic management market.
Accordingly, we intend to continue to invest heavily in sales and marketing,
promotion of the F5 brand, customer service and support, research and
development, operating infrastructure and general and administrative staff to
support our growth. As a result of these investments, we expect that our
operating expenses will increase significantly and that we will continue to
incur substantial operating losses for the foreseeable future. To achieve and
maintain profitability we will need to increase our net revenues significantly.
Although we have experienced rapid growth in net revenues in recent periods, we
may not be able to sustain these growth rates or achieve or sustain
profitability.

    We have recorded a total of $6.2 million of unearned compensation costs
since our inception through June 30, 1999. These charges represent the
difference between the exercise price and the deemed fair value of certain stock
options granted to our employees and outside directors. These options generally
vest ratably over a four-year period. We are amortizing these costs over the
vesting period of the options and have recorded unearned compensation charges of
$69,000 and $420,000 for the years ended September 30, 1997 and 1998,
respectively, and $205,000 and $1.8 million for the nine months ended June 30,
1998 and 1999, respectively.

    We expect to recognize amortization expense related to unearned compensation
of approximately $700,000 in the quarter ended September 30, 1999, $1.8 million,
$961,000 and $408,000 during the years ended September 30, 2000, 2001 and 2002,
respectively. We cannot guarantee, however, that we will not accrue additional
unearned compensation costs in the future or that our current estimate of these
costs will prove accurate, either of which events could seriously harm our
business and results of operations.

    In view of the rapidly changing nature of our business and our limited
operating history, we believe that period-to-period comparisons of net revenues
and operating results are not necessarily meaningful and should not be relied
upon as indications of future performance. This is particularly true of
companies such as ours that operate in new and rapidly evolving markets.

RESULTS OF OPERATIONS

    The following table sets forth certain financial data as a percentage of
total net revenues for the periods indicated. Data for the period from
inception, February 26, 1996, to September 30, 1996, are not presented because
we did not have product revenues during that period. Further, we believe amounts
from February 26, 1996 through September 30, 1996 are not comparable to the year
ended September 30, 1997

                                       18
<PAGE>
due to different lengths of the respective periods and the rapid acceleration of
our activities and related expenses throughout the 1997 period.
<TABLE>
<CAPTION>
                                                                                  YEAR ENDED          NINE MONTHS ENDED
                                                                                SEPTEMBER 30,              JUNE 30,
                                                                             --------------------  ------------------------
<S>                                                                          <C>        <C>        <C>            <C>
                                                                               1997       1998         1998         1999
                                                                             ---------  ---------  -------------  ---------

<CAPTION>
                                                                                                    (UNAUDITED)
<S>                                                                          <C>        <C>        <C>            <C>
STATEMENT OF OPERATIONS DATA:
Net revenues:
  Products.................................................................      100.0%      84.3%        85.1%        84.4%
  Services.................................................................         --       15.7         14.9         15.6
                                                                             ---------  ---------        -----    ---------
    Total net revenues.....................................................      100.0      100.0        100.0        100.0

Cost of net revenues:
  Products.................................................................       31.0       22.3         23.3         21.9
  Services.................................................................         --        6.4          5.7          7.0
                                                                             ---------  ---------        -----    ---------
    Total cost of net revenues.............................................       31.0       28.7         29.0         28.9
                                                                             ---------  ---------        -----    ---------

    Gross margin...........................................................       69.0       71.3         71.0         71.1

Operating expenses:
  Sales and marketing......................................................      246.8       79.4         81.8         64.8
  Research and development.................................................      248.5       37.0         35.5         27.1
  General and administrative...............................................      167.2       21.3         23.1         15.3
  Amortization of unearned compensation....................................       30.1        8.6          6.9         12.8
                                                                             ---------  ---------        -----    ---------
    Total operating expenses...............................................      692.6      146.3        147.3        120.0
                                                                             ---------  ---------        -----    ---------
Loss from operations.......................................................     (623.6)     (75.0)       (76.3)       (48.9)
Interest income (expense), net.............................................      (12.2)      (0.1)        (0.7)         1.3
                                                                             ---------  ---------        -----    ---------
Net loss...................................................................     (635.8)%     (75.1)%       (77.0)%     (47.6)%
                                                                             ---------  ---------        -----    ---------
                                                                             ---------  ---------        -----    ---------
</TABLE>

NINE MONTHS ENDED JUNE 30, 1998 (UNAUDITED) AND 1999

    Net Revenues:

    Net revenues consist of sales of our products and services, which include
software licenses and services. Services include revenue from service and
support agreements provided as part of the initial product sale, sales of
extended service and support contracts and consulting services.

    PRODUCT REVENUES.  Product revenues increased by 368.0% from $2.5 million
for the nine months ended June 30, 1998 to $11.9 million for the nine months
ended June 30, 1999. This increase in product revenues was due primarily to an
increase in the quantity of our products sold through our sales direct and
indirect channels including the sales of our new products.

    SERVICE REVENUES.  Service revenues increased by 393.2% from $444,000 for
the nine months ended June 30, 1998 to $2.2 million for the nine months ended
June 30, 1999. This increase was due primarily to an increase in the installed
base of our products which resulted in increased revenues from service and
support contracts.

    As our net revenue base increases, we do not believe we can sustain
percentage growth rates of net revenues that we have experienced historically.

                                       19
<PAGE>
    Cost of Net Revenues:

    Cost of net revenues consists primarily of out-sourced hardware components
and manufacturing, fees for third-party software products integrated into our
products, service and support personnel and an allocation of our facilities and
depreciation expenses.

    COST OF PRODUCT REVENUES.  Cost of product revenues increased 344.5%, from
$694,000 for the nine months ended June 30, 1998 to $3.1 million for the nine
months ended June 30, 1999. Cost of product revenues decreased as a percent of
product revenues from 27.4% for the nine months ended June 30, 1998, to 26.0%
for the nine months ended June 30, 1999. The increase in absolute dollars was
due primarily to an increase in product revenues. The decrease in cost of
product revenues as a percentage of product revenues was the result of higher
utilization of manufacturing operations, including increased economies of scale
achieved from an increase in production.

    COST OF SERVICE REVENUES.  Cost of service revenues increased 470.8%, from
$171,000 for the nine months ended June 30, 1998 to $976,000 for the nine months
ended June 30, 1999. Cost of service revenues increased as a percent of service
revenues from 38.5% for the nine months ended June 30, 1998 to 44.6% for the
nine months ended June 30, 1999. The increases in cost of service revenues in
absolute dollars and as a percent of service revenues was due primarily to
increases in service and support personnel.

    SALES AND MARKETING.  Our sales and marketing expenses consist primarily of
salaries, commissions and related benefits of our sales and marketing staff,
costs of our marketing programs, including public relations, advertising and
trade shows and an allocation of our facilities and depreciation expenses. Sales
and marketing expenses increased by 273.6%, from $2.4 million for the nine
months ended June 30, 1998 to $9.1 million for the nine months ended June 30,
1999. This increase was due to an increase in sales and marketing personnel and
professional services personnel from 22 to 67, and increased advertising and
promotional activities. We expect to increase sales and marketing expenses in
order to grow net revenues and expand our brand awareness.

    RESEARCH AND DEVELOPMENT.  Our research and development expenses consist
primarily of salaries and related benefits for our product development personnel
and an allocation of our facilities and depreciation expenses. Research and
development expenses increased by 259.8%, from $1.1 million for the nine months
ended June 30, 1998 to $3.8 million for the nine months ended June 30, 1999.
This increase was due to an increase in product development personnel from 21 to
54. Our future success is dependent in large part on the continued enhancement
of our current products and our ability to develop new, technologically advanced
products that meet the sophisticated needs of our customers. We expect research
and development expenses to increase in future periods.

    GENERAL AND ADMINISTRATIVE.  Our general and administrative expenses consist
primarily of salaries, benefits and related costs of our executive, finance,
human resource and legal personnel, third-party professional service fees, and
an allocation of our facilities and depreciation expenses. General and
administrative expenses increased by 210.9% from $690,000 for the nine months
ended June 30, 1998 to $2.1 million for the nine months ended June 30, 1999.
This increase was due primarily to an increase in general and administrative
personnel from 15 to 30. We expect general and administrative expenses to
increase as we expand our staff, further develop our internal information
systems and incur costs associated with being a publicly held company.

    UNEARNED COMPENSATION.  We recorded unearned compensation charges of
$205,000 and $1.8 million for the nine months ended June 30, 1998 and 1999,
respectively. See Note 8 of notes to our financial statements.

    INTEREST INCOME (EXPENSE) NET.  Interest income consists of earnings on our
cash and cash equivalent balances offset by interest expense associated with
debt obligations. Net interest expense was $21,000 for

                                       20
<PAGE>
the nine months ended June 30, 1998 compared to net interest income of $186,000
for the nine months ended June 30, 1999. This increase was due primarily to the
investment of the proceeds received from the initial public offering in June
1999.

    INCOME TAXES.  There was no provision for federal or state income taxes for
any period as we have incurred operating losses since inception. As of June 30,
1999, we had approximately $8.8 million of net operating loss carryforwards for
federal income tax purposes. Utilization of the net operating loss carryforwards
may be subject to annual limitations due to the ownership change limitations
contained in the Internal Revenue Code of 1986 and similar state provisions.
Annual limitations may result in the expiration of the net operating losses
before we can utilize them. The federal net operating loss carryforwards will
expire at various dates beginning in 2011 through 2018 if we do not use them.
See Note 5 of notes to our financial statements.

YEARS ENDED SEPTEMBER 30, 1997 AND 1998

    Net Revenues:

    PRODUCT REVENUES.  Product revenues increased by 1,698.7% from $229,000 in
1997 to $4.1 million in 1998. This increase was due primarily to an increase in
the quantity of our products sold.

    SERVICE REVENUES.  There were no service revenues in 1997 because the
initial product sales during that period did not include a service and support
contract. Beginning in fiscal year 1998, our products included a service and
support contract. Service revenues were $770,000 in 1998. This increase in
service revenues was due to an increase in the installed base of our products
which included a service and support contract.

    Cost of Net Revenues:

    COST OF PRODUCT REVENUES.  Cost of product revenues increased by 1,436.6%
from $71,000 in 1997 to $1.1 million in 1998. This increase was due primarily to
the increase in our products sold. Cost of product revenues as a percentage of
net revenues decreased from 31.0% to 26.5% due to a decrease in direct product
costs including costs of manufacturing personnel as a percentage of revenue.

    COST OF SERVICE REVENUES.  Cost of service revenues was $314,000 in 1998.
Cost of service revenues as a percent of service revenues was 40.8% in 1998. We
expect that the cost of service revenues will fluctuate in the future based on
the rate of increase in service and support personnel compared with increases in
service revenues.

    SALES AND MARKETING.  Our sales and marketing expenses increased by 586.9%,
from $565,000 in 1997 to $3.9 million in 1998. This increase was due primarily
to investing in our sales and marketing infrastructure, both domestically and
internationally. These investments included an increase in our sales and
marketing and professional services personnel from 7 to 37, recruiting fees,
travel expenses, and increased marketing activities, including advertising,
trade shows and other promotional expenses. Sales and marketing expenses
decreased from 246.8% of net revenues in 1997 to 79.4% of net revenues in 1998.
This percentage decrease was due primarily to our net revenues growing faster
than our sales and marketing expenses.

    RESEARCH AND DEVELOPMENT.  Our research and development expenses increased
by 218.1% from $569,000 in 1997 to $1.8 million in 1998. This increase was due
primarily to an increase in our software engineers and other technical staff
from 9 to 27. Research and development expenses decreased from 248.5% of our net
revenues in 1997 to 37.0% of our net revenues in 1998. This percentage decrease
was due primarily to our net revenues growing faster than our research and
development expenses.

                                       21
<PAGE>
    GENERAL AND ADMINISTRATIVE.  Our general and administrative expenses
increased by 171.8% from $383,000 in 1997 to $1.0 million in 1998. This increase
was due primarily to an increase in general and administrative personnel from 4
to 16. General and administrative costs decreased from 167.2% of our net
revenues in 1997 to 21.3% of our net revenues in 1998. This percentage decrease
was due primarily to our net revenues growing faster than our general and
administrative expenses.

    INTEREST INCOME (EXPENSE), NET.  Net interest expense was $28,000 in 1997
compared to net interest expense of $4,000 in 1998. This decrease was due
primarily to increased interest earned on cash and cash equivalents received
from the sale of our preferred stock in August 1998.

QUARTERLY RESULTS OF OPERATIONS

    The following tables present our unaudited quarterly results of operations
for the seven quarters ended June 30, 1999 in dollars and as a percentage of net
revenues. You should read the following tables in conjunction with our financial
statements and related notes in this prospectus. We have prepared this unaudited
information on the same basis as the audited financial statements. These tables
include all adjustments, consisting only of normal recurring adjustments that we
consider necessary for a fair presentation of our operating results for the
quarters presented. You should not draw any conclusions about our future results
from the results of operations for any quarter.

<TABLE>
<CAPTION>
                                                                             THREE MONTHS ENDED
                                          -----------------------------------------------------------------------------------------
                                            DEC. 31,     MARCH 31,   JUNE 30,     SEPT. 30,       DEC. 31,     MARCH 31,   JUNE 30,
                                              1997         1998        1998         1998            1998         1999        1999
                                          ------------   ---------   --------   -------------   ------------   ---------   --------
                                                                               (IN THOUSANDS)
                                                                                 (UNAUDITED)
<S>                                       <C>            <C>         <C>        <C>             <C>            <C>         <C>
Net revenues:
  Products..............................     $ 742        $  866     $   929       $ 1,582        $ 2,282       $3,146     $ 6,444
  Services..............................       100           129         215           326            413          616       1,161
                                             -----       ---------   --------   -------------   ------------   ---------   --------
    Total net revenues..................       842           995       1,144         1,908          2,695        3,762       7,605

Cost of net revenues:
  Products..............................       201           202         291           397            624          825       1,636
  Services..............................         9            47         115           143            196          384         396
                                             -----       ---------   --------   -------------   ------------   ---------   --------
    Total cost of net revenues..........       210           249         406           540            820        1,209       2,032
                                             -----       ---------   --------   -------------   ------------   ---------   --------

    Gross profit........................       632           746         738         1,368          1,875        2,553       5,573
                                             -----       ---------   --------   -------------   ------------   ---------   --------

Operating expenses:
  Sales and marketing...................       555           787       1,097         1,442          2,216        2,887       4,010
  Research and development..............       194           340         525           751          1,020        1,324       1,466
  General and administrative............       202           236         252           351            525          666         954
  Amortization of unearned
    compensation........................        31            60         114           215            368          670         759
                                             -----       ---------   --------   -------------   ------------   ---------   --------
    Total operating expenses............       982         1,423       1,988         2,759          4,129        5,547       7,189
                                             -----       ---------   --------   -------------   ------------   ---------   --------
Loss from operations....................      (350)         (677)     (1,250)       (1,391)        (2,254)      (2,994)     (1,616)
Interest income (expense), net..........       (23)            4          (2)           17             58           31          97
                                             -----       ---------   --------   -------------   ------------   ---------   --------
Net loss................................     $(373)       $ (673)    $(1,252)      $(1,374)       $(2,196)      $(2,963)   $(1,519)
                                             -----       ---------   --------   -------------   ------------   ---------   --------
                                             -----       ---------   --------   -------------   ------------   ---------   --------
</TABLE>

                                       22
<PAGE>

<TABLE>
<CAPTION>
                                                                             THREE MONTHS ENDED
                                          -----------------------------------------------------------------------------------------
                                            DEC. 31,     MARCH 31,   JUNE 30,     SEPT. 30,       DEC. 31,     MARCH 31,   JUNE 30,
                                              1997         1998        1998         1998            1998         1999        1999
                                          ------------   ---------   --------   -------------   ------------   ---------   --------
                                                                                 (UNAUDITED)
<S>                                       <C>            <C>         <C>        <C>             <C>            <C>         <C>
Net revenues:
  Products..............................      88.1%         87.0%       81.2%        82.9%          84.7%         83.6%       84.7%
  Services..............................      11.9          13.0        18.8         17.1           15.3          16.4        15.3
                                             -----       ---------   --------       -----          -----       ---------   --------
    Total net revenues..................     100.0         100.0       100.0        100.0          100.0         100.0       100.0

Cost of net revenues:
  Products..............................      23.9          20.3        25.4         20.8           23.1          21.9        21.5
  Services..............................       1.0           4.7        10.1          7.5            7.3          10.2         5.2
                                             -----       ---------   --------       -----          -----       ---------   --------
    Total cost of net revenues..........      24.9          25.0        35.5         28.3           30.4          32.1        26.7
                                             -----       ---------   --------       -----          -----       ---------   --------

    Gross margin........................      75.1          75.0        64.5         71.7           69.6          67.9        73.3
                                             -----       ---------   --------       -----          -----       ---------   --------

Operating expenses:
  Sales and marketing...................      65.9          79.1        95.9         75.5           82.2          76.7        52.7
  Research and development..............      23.0          34.2        45.9         39.4           37.8          35.2        19.3
  General and administrative............      24.0          23.7        22.0         18.4           19.5          17.8        12.5
  Amortization of unearned
    compensation........................       3.7           6.0        10.0         11.3           13.7          17.8        10.0
                                             -----       ---------   --------       -----          -----       ---------   --------
    Total operating expenses............     116.6         143.0       173.8        144.6          153.2         147.5        94.5
                                             -----       ---------   --------       -----          -----       ---------   --------
Loss from operations....................     (41.5)        (68.0)     (109.3)       (72.9)         (83.6)        (79.6)      (21.2)
Interest income (expense), net..........      (2.8)          0.4        (0.1)         0.9            2.1           0.8         1.3
                                             -----       ---------   --------       -----          -----       ---------   --------
Net loss................................     (44.3)%       (67.6)%    (109.4)%      (72.0)%        (81.5)%       (78.8)%     (19.9)%
                                             -----       ---------   --------       -----          -----       ---------   --------
                                             -----       ---------   --------       -----          -----       ---------   --------
</TABLE>

    Our quarterly operating results have fluctuated significantly and we expect
that future operating results will be subject to similar fluctuations for a
variety of factors, many of which are substantially outside our control. See
"Risk Factors--Our quarterly operating results are volatile and future operating
results remain uncertain."

LIQUIDITY AND CAPITAL RESOURCES

    From our inception through May 1999, we financed our operations and capital
expenditures primarily through the sale of approximately $12.4 million in equity
securities. In June 1999 we completed an initial public offering of 2,860,000
shares of common stock and raised approximately $25.5 million, net of offering
costs.

    As of June 30, 1999, we had a $2.0 million working capital line of credit
with a lender. At June 30, 1999, there were no borrowings outstanding under this
line of credit. This line of credit was not renewed when it expired on August
31, 1999.

    Cash used in our operating activities was $1.7 million for the nine months
ended June 30, 1998, and $3.9 million for the nine months ended June 30, 1999.
These net cash outflows resulted from operating losses as well as increases in
accounts receivable due to increased sales and other current assets and were
partially offset by increases in accounts payable, accrued liabilities and
deferred revenues. The Company anticipates that in the future it will offer
financing to certain resellers. To the extent such financing is offered cash
used in operating activities will increase to fund the increase in outstanding
accounts receivables.

    Cash used in investing activities was $580,000 for the nine months ended
June 30, 1998 and $1.5 million for the nine months ended June 30, 1999,
substantially all of which was used for the purchase

                                       23
<PAGE>
of property and equipment. We expect capital expenditures to continue to
increase through the end of 1999, due to the costs of expansion and expenditures
for information systems and test equipment.

    As of June 30, 1999, our principal commitment consisted of obligations
outstanding under operating leases. In March 1999 we began leasing approximately
20,000 square feet in a facility located in Seattle, Washington for a term of 60
months. In July 1999, we agreed to lease an additional 8,000 square feet in a
facility located in Seattle, Washington, for a term of 84 months. The annual
cost of these leases is approximately $561,000, subject to annual adjustments.
We have also signed a lease for approximately 84,000 square feet of new office
space in Seattle, Washington in a building which is currently under
construction. This lease will commence on approximately July 1, 2000 with a term
of 12 years. The annual cost of this lease is approximately $2,000,000, subject
to annual adjustments plus expenses. Our obligation under the lease is
collateralized by a secured letter of credit in the amount of $2.5 million.
Although we have no other material commitments, we anticipate a substantial
increase in our capital expenditures and lease commitments consistent with
anticipated growth in our operations, infrastructure and personnel. In the
future we may also require a larger inventory of products in order to provide
better availability to customers and achieve purchasing efficiencies. We expect
that the net proceeds from this offering, our existing cash balances and cash
from operations will be sufficient to meet our currently anticipated working
capital and capital expenditures for the foreseeable future.

MARKET RISK DISCLOSURES

    We do not hold derivative financial instruments or equity securities in our
investment portfolio. Our cash equivalents consist of high-quality securities,
as specified in our investment policy guidelines. The policy limits the amount
of credit exposure to any one issue or issuer to a maximum of 20% of the total
portfolio with the exception of treasury securities, commercial paper, and money
market funds, which are exempt from size limitation. The policy limits all
short-term investments to mature in two years or less, with the average maturity
being one year or less. These securities are subject to interest rate risk and
will decrease in value if interest rates increase.

RECENT ACCOUNTING PRONOUNCEMENTS

    As of October 1, 1998 we adopted Financial Accounting Standards Board
Statement No. 130, "Reporting Comprehensive Income," which establishes standards
for reporting and displaying comprehensive income and its components in a full
set of general-purpose financial statements. We had no material components of
comprehensive income. The adoption of this statement has had no impact on our
financial position, shareholders' equity (deficit), results of operations or
cash flows. Accordingly, our comprehensive loss for the nine months ended June
30, 1999 is equal to our reported loss.

    Additionally, the Financial Accounting Standards Board issued Statement No.
131, "Disclosures about Segments of an Enterprise and Related Information,"
which establishes standards for the way business enterprises report information
in annual statements and interim financial reports regarding operating segments,
products and services, geographic areas and major customers. This statement is
effective for financial statements for fiscal years beginning after December 15,
1997. The adoption of this statement did not have a material impact on the way
we report information in our financial statements.

    In March 1998, the American Institute of Certified Public Accountants issued
Statement of Position 98-1 ("SOP 98-1"), "Accounting for the Costs of Computer
Software Developed or Obtained for Internal Use," which establishes guidelines
for the accounting for the costs of all computer software developed or obtained
for internal use. We are required to adopt SOP 98-1 for the fiscal year
beginning in October 1999. Our adoption of SOP 98-1 is not expected to have a
material impact on our financial statements.

    In June 1998, the Financial Accounting Standards Board issued Statement No.
133 of Financial Accounting Standards, "Accounting for Derivative Instruments
and Hedging Activities." This statement requires that all derivative instruments
be recorded on the balance sheet at their fair value. Changes in the

                                       24
<PAGE>
fair value of derivatives are recorded each period in current earnings or other
comprehensive income, depending on whether a derivative is designated as a part
of a hedge transaction and, if it is, the type of hedge transaction. In July
1999, the FASB issued SFAS No. 137, "Accounting for Derivative Instruments and
Hedging Activities--Deferral of the Effective Date of FASB Statement No. 133."
SFAS No. 137 deferred the effective date of SFAS No. 133 until fiscal years
beginning after June 15, 2000. We do not use derivative instruments, therefore
the adoption of this statement will not have any effect on our results of
operations or financial position.

YEAR 2000 COMPLIANCE

    BACKGROUND OF YEAR 2000 ISSUES.  Many currently installed computer and
communications systems and software products are unable to distinguish 21(st)
century dates from 20(th) century dates. This situation could result in system
failures or miscalculations causing business disruptions. As a result, many
companies' software and computer and communications systems may need to be
upgraded or replaced to become Year 2000 compliant.

    OUR PRODUCT TESTING AND LICENSING.  We have tested all of our current
products for Year 2000 compliance. We derived our testing method from our review
and analysis of the Year 2000 testing practices of other software vendors,
relevant industry Year 2000 compliance standards and the specific functionality
and operating environments of our products. The tests are run on all supported
platforms for each current release of our product and include testing for date
calculations and internal storage of date information with test numbers starting
in 1999 and going beyond the Year 2000. Based on these tests, we believe our
products to be Year 2000 compliant with respect to date calculations and
internal storage of date information.

    CUSTOMER CLAIMS.  We may be subject to customer claims to the extent our
products fail to operate properly as a result of the occurrence of the date
January 1, 2000. Liability may result to the extent our products are not able to
store, display, calculate, compute and otherwise process date-related data. We
could also be subject to claims based on the failure of our products to work
with software or hardware from other vendors.

    OUR EXTERNAL VENDORS.  We periodically verify Year 2000 compliance by
external vendors that supply us with material software and information systems
and communicate with our significant suppliers to determine their Year 2000
readiness. As part of our assessment, we periodically evaluate the level of
validation we require of third parties to ensure their Year 2000 readiness. To
date, we have not encountered any material Year 2000 problems with software and
information systems provided to us by third parties.

    OUR INTERNAL SYSTEMS.  We periodically review our internal management
information and other systems to identify any products, services or systems that
may not be Year 2000 compliant and to take corrective action when required. To
date, we have not encountered any material Year 2000 problems with our computer
systems or any other equipment that might be subject to such problems.

    COSTS OF ADDRESSING YEAR 2000 COMPLIANCE.  Based on our preliminary
evaluations, we do not believe we will incur significant expenses or be required
to invest heavily in computer system improvements to be Year 2000 compliant. We
do not believe the cost of remediation for Year 2000 non-compliance issues
identified to date will exceed $50,000. However, significant uncertainty exists
concerning the potential costs and effects associated with Year 2000 compliance.
Any Year 2000 compliance problem experienced by us or our customers could
decrease demand for our products which could seriously harm our business and
results of operations.

    CONTINGENCY PLANNING.  We are formulating a contingency plan at this time
and expect to have specific contingency plans in place prior to November 30,
1999.

                                       25
<PAGE>
                                    BUSINESS

    THE FOLLOWING BUSINESS SECTION CONTAINS FORWARD-LOOKING STATEMENTS RELATING
TO FUTURE EVENTS OR THE FUTURE FINANCIAL PERFORMANCE OF F5, WHICH 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 THOSE SET FORTH UNDER "RISK FACTORS" AND ELSEWHERE IN THIS PROSPECTUS.

OVERVIEW

    F5 is a leading provider of integrated Internet traffic management solutions
designed to improve the availability and performance of mission-critical
Internet-based servers and applications. Our products monitor and manage local
and geographically dispersed servers and intelligently direct traffic to the
server best able to handle a user's request. Our products are designed to help
prevent system failure and provide timely responses to user requests and data
flow. Our BIG/ip-Registered Trademark- and 3DNS-Registered Trademark-
Controllers, when combined with our see/IT-TM- Network Manager, help
organizations optimize their network server availability and performance and
cost-effectively manage their Internet infrastructure. Our solutions are used by
organizations who rely on the Internet as a fundamental component of their
business. Our customers include Internet service providers, such as Exodus
Communications, Frontier GlobalCenter, PSINet, and MCI WorldCom, e-commerce
companies and many other organizations that employ high-traffic Internet sites.
We have sold our products to over 600 end-customers as of August 31, 1999.

INDUSTRY BACKGROUND

    The Internet has emerged as a critical commerce and communications platform
for businesses and consumers worldwide. International Data Corporation estimates
that there were approximately 100 million Internet users at the end of 1998 and
anticipates this number will grow to approximately 320 million by 2002. This
dramatic growth in the number of Internet users coupled with the increased
availability of powerful new tools and equipment that enable the development,
processing and distribution of data across the Internet have led to a
proliferation of Internet-based applications and services, such as e-commerce,
e-mail, electronic file transfers and online interactive applications. At the
same time that the number of users of, and uses for, the Internet has increased
significantly, the complexity and volume of Internet traffic has increased
dramatically. According to UUNet estimates, Internet traffic doubles every 100
days.

    As a result of the Internet's growing popularity and capabilities, numerous
businesses have come to rely on it as a fundamental commerce and communications
tool. For example, a growing number of organizations, such as Web hosting and
e-commerce companies, rely primarily on the Internet to transact business. In
addition, many businesses are using the Internet to deploy mission-critical
business applications in browser-based intranet and extranet computing
environments. Failure to deliver the expected availability and performance for
these Internet-based applications can result in a significant cost to the
organization.

    This widespread proliferation in the use and importance of the Internet has
strained many organizations' network infrastructures. In order to support the
dramatic increases in Internet use and traffic, many organizations have
aggressively expanded network server capacity. According to IBM, servers are
being connected to the Internet at a rate of 53,000 per month. Network
infrastructures are further strained by unpredictable traffic, the complexity of
the network environment and the increased variety of data, including multimedia
components and video clips. In this environment, organizations often deploy
multiple servers in a group, or array, which contains individual
application-specific servers or redundant servers that operate together as a
virtual large server. Server arrays can reduce single points of failure and be a
cost-effective way to increase the potential capacity of the system by providing
the flexibility to add additional servers to the array as needed. The practice
of geographically dispersing server arrays to help prevent system failure and
direct traffic more efficiently is also a growing trend.

                                       26
<PAGE>
    While additional servers, redundant server configurations and geographically
dispersed server sites help address an organization's rapidly increasing
traffic, they also increase the organization's need for sophisticated Internet
traffic management tools to help manage the availability and performance of its
servers and applications. For optimal server array performance, intelligent
devices are required to direct traffic and synchronize content across local and
geographically dispersed servers. These intelligent devices, or load balancers,
identify which server, whether local or remote, is best able to handle user
requests.

    Most currently available Internet traffic management products are extensions
to hardware-based routers, which lack the robust functionality required to
support current mission-critical Internet-based servers and applications. These
products are typically not designed to address application availability, nor do
they meet the manageability and scalability required by organizations who depend
on the Internet as a fundamental commerce and communications tool. As a result,
we believe that traditional traffic management products do not adequately
address the need to manage traffic flows and ensure the availability of
mission-critical servers and applications in the rapidly changing Internet
environment.

F5 SOLUTION

    We develop, market and support cost-effective, integrated Internet traffic
management solutions designed to ensure that mission-critical Internet-based
servers and applications are continuously available and perform reliably. Our
products monitor and manage locally and geographically dispersed servers and
intelligently direct traffic to the server best able to handle the user request.
We believe that our products deliver Internet quality control by providing the
following key benefits:

    HIGH SYSTEM AVAILABILITY.  Our integrated suite of products works with
servers deployed in a redundant server array over a local or wide area network
to enhance network performance and reduce single points of failure. Our
solutions continuously monitor network performance to enable real-time detection
of server, application and content degradation or failure. Based on this
information, our solutions automatically direct user requests to functioning
servers and applications. Our products also enable network administrators to
deploy new servers and take individual servers offline for routine maintenance
without disrupting service to end users.

    INCREASED PERFORMANCE.  Our products provide a significant performance
improvement over other current approaches. Our solutions monitor server and
application response time and verify content. This information is used to
intelligently direct user requests to the server with the fastest response time.
By intelligently allocating traffic throughout the network, our solutions reduce
server overload conditions that may cause performance degradation.

    COST-EFFECTIVE SCALABILITY.  Our solutions enable more efficient utilization
of existing server capacity by intelligently allocating traffic among servers.
This capability allows organizations to optimize the capacity of existing
servers and, as traffic volume dictates, cost-effectively expand server capacity
through incremental additions of relatively low cost servers rather than
upgrading to larger, more expensive servers. Our solutions can be used with
multiple heterogeneous hardware platforms, allowing organizations to protect
their investments in their legacy hardware installations as well as integrate
future hardware investments.

    EASIER NETWORK MANAGEABILITY.  Our products collect information that can be
used to facilitate network management and planning from a central location.
Leveraging our products' strategic location in the network, our solutions
collect data that is crucial for traffic analysis and apply proprietary trend
and analysis tools that synthesize this data so that network managers can
forecast network requirements more accurately. In addition, we are in the
process of developing solutions to automatically synchronize content across
remote locations, thereby helping to ensure users access to the same content
regardless of server location.

    ENHANCED NETWORK CONTROL.  Our solutions enable organizations to prioritize
and arrange network traffic based on user-defined criteria to meet their
specific needs. For example, our products may be

                                       27
<PAGE>
configured to utilize the most cost-efficient communication links or,
alternatively, to achieve the most rapid response time.

STRATEGY

    Our objective is to be the leading provider of integrated Internet traffic
management solutions designed to optimize network server availability and
performance. Key components of our strategy include:

    OFFER A COMPLETE INTERNET TRAFFIC MANAGEMENT SOLUTION.  We plan to continue
expanding our existing suite of products to provide a complete Internet traffic
management solution that further optimizes the availability and performance of
network servers and applications. To support this objective, we have recently
introduced our see/IT-TM- Network Manager that communicates with our BIG/ip and
3DNS Controllers to enable real-time network monitoring and pro-active network
management. Furthermore, we are currently developing our global/SITE-TM-
Controller that is designed to ensure data integrity by automatically
synchronizing content across local and geographically dispersed network servers.
To further support our suite of products, we intend to continue to invest in our
professional services group to provide the installation, training and support
services required to help our customers optimize their use of our Internet
traffic management solutions.

    INVEST IN TECHNOLOGY TO CONTINUE TO MEET CUSTOMER NEEDS.  We plan to
continue to invest in research and development to provide our customers with
complete Internet traffic management solutions that meet their needs. Our
current technology platform has been designed to quickly and easily expand the
features and functionalities of our suite of products as well as develop
additional products that address the complex and changing needs of our
customers. We are also in the process of developing specialized software modules
that will allow our customers to purchase products with specific features based
on their specific requirements.

    EXPAND SALES CHANNELS AND GEOGRAPHIC SCOPE OF SALES.  We plan to invest
significant resources to expand our direct sales force and further develop our
indirect sales channels. In addition to maintaining a strong direct sales force,
we plan to expand our indirect sales channels through leading industry
resellers, original equipment manufacturers, systems integrators, Internet
service providers and other channel partners. Furthermore, we plan to expand
sales of our Internet traffic management solutions to government entities. We
also plan to aggressively develop our direct and indirect international sales
capabilities, particularly in selected countries in the European and Asia
Pacific markets.

    BUILD AND EXPAND RELATIONSHIPS WITH STRATEGIC PARTNERS.  We plan to
capitalize on products, technologies and channels that may be available through
partners. We currently have an OEM relationship with Cabletron and a licensing
agreement for our BIG/ip load-balancing technology with Extreme Networks. We
continue to seek relationships with partners that will enable us to increase the
market opportunity for our products and technologies.

    LEVERAGE OUR MARKET LEADERSHIP TO CONTINUE TO BUILD THE F5 BRAND.  We plan
to continue building brand awareness that positions us as one of the leading
providers of Internet traffic management solutions. Our goal is for the F5 brand
to be synonymous with superior network performance, high quality customer
service and ease of use. To achieve these objectives, we plan to increase our
investments in a broad range of marketing programs, including active tradeshow
participation, advertising in print publications, direct marketing, high-profile
Web events and our Internet site.

    PURSUE STRATEGIC ACQUISITIONS.  We may selectively pursue strategic
acquisitions for products and technologies that will complement or expand our
existing Internet traffic management solutions.

                                       28
<PAGE>
PRODUCTS AND TECHNOLOGY

    We have developed BIG/ip, 3DNS and see/IT-TM- as a suite of Internet traffic
management products that facilitate high performance, high availability and
scalable access to network server arrays located at a single site or across
multiple, geographically dispersed sites. Our suite of products helps to ensure
that Web servers can respond to ever-increasing Internet traffic. The following
is a summary of our products currently available and under development:

<TABLE>
<CAPTION>
- -------------------------------------------------------------------------------------------

           PRODUCT NAME                          DESCRIPTION              INTRODUCTION DATE
<S>                                  <C>                                  <C>
BIG/ip-Registered Trademark-         Intelligent load balancer for local  July 1997
Controller                           area networks
3DNS-Registered Trademark-           Intelligent load balancer for wide   September 1998
Controller                           area networks
see/IT-TM- Network Manager           Traffic analysis and network         April 1999
                                     management software application for
                                     BIG/ip and 3DNS
global/SITE-TM- Controller           File replication and                 Under development
                                     synchronization controller for
                                     managing content across
                                     geographically dispersed Internet
                                     sites
</TABLE>

    BIG/IP CONTROLLER.  BIG/ip is an intelligent load balancer consisting of our
proprietary software, which we load on a pre-configured, industry-standard
hardware platform. Situated between a network's routers and server array, BIG/ip
continuously monitors the array of local servers to ensure application
availability and performance and automatically directs user requests to the
server best able to handle these requests. By quickly detecting application,
server and network failures and directing service toward those servers and
applications that are functioning properly, BIG/ip is designed to help prevent
system failure and provide timely responses to user requests and data flow.
BIG/ip offers a comprehensive choice of load-balancing algorithms that enables
an organization to choose a load-balancing configuration that best suits its
particular needs. Additionally, BIG/ip actively queries and checks content
received from applications, thereby helping to ensure the quality of Web
content. Thus, if a server and application are responding to users' requests
with incorrect content, BIG/ip redirects requests to those servers and
applications that are responding properly.

    BIG/ip is compatible with any system that uses the standard Internet
communication method, also known as Internet protocol or IP, and can operate
with multiple, heterogeneous hardware platforms. This enables organizations to
leverage their existing infrastructure without limiting their options to meet
future network needs. BIG/ip supports a wide variety of network protocols,
including Web, e-mail, audio, video, database and file transfer protocol, which
is the standard method of transfering files over the Internet. BIG/ip also
manages traffic for network devices such as firewalls that prevent unauthorized
access to a network system, cache servers that store frequently accessed Web
content and multimedia servers, to help provide reliable content availability
for end users. BIG/ip's ability to intelligently distribute traffic across
server arrays reduces the need for increasingly larger and more expensive
servers to accommodate increases in network traffic. This configuration also
reduces the single point of failure inherent with a single large server and
allows for the orderly addition of new servers or the routine maintenance or
upgrades of servers without disrupting service to the end user. A typical
configuration of redundant BIG/ip Controllers located between the server array
and network is shown below.

                                       29
<PAGE>
                             [ILLUSTRATION]

    Illustration of redundant BIG/ip Controllers sitting between an
    organization's server array and network

    Additional BIG/ip features include:

    - SECURE SOCKETS LAYER SESSION PERSISTENCE enables server arrays to support
      e-commerce and other applications in a secure, cost-effective and scalable
      environment.

    - SECURE SERVER PROTECTION protects against unauthorized use of the network
      server array.

    - RATE SHAPING allows priority levels to be assigned to specific types of
      traffic.

    - PACKET FILTERING enables content providers to direct network traffic to
      servers based on user-definable criteria for increased network security
      and performance.

    - BIG/CONFIG, a simple point-and-click browser-based installation and
      configuration tool, facilitates remote monitoring and administration of
      the network in a secure environment.

    3DNS CONTROLLER.  3DNS is an intelligent load balancer that manages and
distributes user requests across wide area networks. 3DNS consists of our
proprietary software, which we load on a pre-configured, industry-standard
hardware platform. Like BIG/ip, 3DNS functions with multiple heterogeneous
hardware platforms and supports a wide variety of network protocols, including
Web, e-mail, audio, video, database and file transfer protocol, and manages
traffic for network devices such as firewalls, cache servers and multimedia
servers.

                                       30
<PAGE>
    When an end-user request is received from a local domain name server or DNS,
3DNS collects network information and communicates with each BIG/ip in the
network to determine the server array with the fastest response time. 3DNS then
sends the request to the BIG/ip at this server array, and the BIG/ip then
directs the request to the individual server best able to handle it. Although
organizations can deploy a single 3DNS in their network configuration, multiple
3DNS Controllers are often deployed within the network to provide redundancy to
help ensure network availability and performance for end users. A typical 3DNS
configuration is shown below:

                             [ILLUSTRATION]

    Illustration of 3DNS Controllers at multiple locations showing the
    interaction of 3DNS with BIG/ip and an organization's network

    Additional 3DNS features include:

    - DYNAMIC LOAD BALANCING optimizes use of available network resources across
      wide area networks.

    - USER-DEFINED PRODUCTION RULES allow organizations to pre-configure traffic
      distribution decisions according to their specific user requirements.

    - SECURE SERVER PROTECTION offers security features for wide area networks
      similar to those BIG/ip provides for local area networks.

    - BIG/CONFIG, a simple point-and-click browser-based installation and
      configuration tool, facilitates remote monitoring and administration of
      the network in a secure environment.

    SEE/IT NETWORK MANAGER.  see/IT is a recently introduced software
application that communicates with BIG/ip and 3DNS to help improve the
management and functionality of an organization's network servers. see/IT, which
runs on an NT server, uses real-time data collected by BIG/ip and 3DNS to
perform crucial traffic analysis management functions. Furthermore, by reviewing
historical patterns, network administrators can build predictive models and
forecast usage, which helps them to intelligently plan and

                                       31
<PAGE>
budget for additional server and bandwidth capacity. see/IT integrates the
BIG/config software module that comes pre-loaded with BIG/ip and 3DNS and
consists of the following two additional Internet browser-based modules:

    - BIG/PICTURE-TM- is a real-time monitoring tool that displays key data on
      network traffic in easy-to-read graphical illustrations, thereby enabling
      network administrators to quickly obtain information regarding network and
      server performance, including data about server status and traffic, number
      of connections, active and inactive IP addresses and the availability of
      individual applications.

    - BIG/ANALYSIS-TM- is a forward-looking trend and analysis tool that uses
      the information generated by BIG/picture to project future network and
      server needs. Network managers and system administrators can use this tool
      to create "what if?" scenarios to help forecast the need for additional
      servers, interface upgrades and other network capacity requirements.

    GLOBAL/SITE CONTROLLER.  global/SITE is a global data management solution
currently under development that has been designed to help organizations
automate publishing, distribution and synchronization of file-based content and
applications to local and geographically dispersed Internet sites. global/SITE
is being developed to work with our other products to provide an integrated
Internet traffic management solution. global/SITE will consist of our
proprietary software, which we will load on a pre-configured, industry-standard
hardware platform and is being developed to intelligently deploy both program
and data files to arrays of heterogeneous Web servers. global/SITE's
configuration database will allow administrators to define standard rules for
content deployment as well as accommodate unique content distribution events as
needed.

PRODUCT DEVELOPMENT

    We believe that our future success depends on our ability to build upon our
current technology platform, expand the features and functionalities of our
suite of Internet traffic management products and develop additional products
that maintain our technological competitiveness. Our product development group,
which is divided along product lines, employs a standard process for the design,
development, documentation and quality control of our Internet traffic
management solutions. As of August 31, 1999, we employed 57 people in this
group. Each product line is headed by a lead architect, who is responsible for
developing the technology behind the product. To help develop the technology,
the lead architects work closely with our customers to better understand their
requirements. Each line also has a product manager, who ensures that the team
develops and delivers a product that satisfies our customers' needs. Software
engineers, who help design and build the products, and technicians, who perform
test engineering, configuration management, quality assurance and documentation
functions, complete our product development teams. The test engineering team
evaluates the overall quality of our products and determines whether they are
ready for release.

    Our product development expenses for fiscal 1996, 1997, 1998 and the nine
months ended June 30, 1999 were $103,000, $569,000, $1.8 million and $3.8
million, respectively. We expect our product development expenses to increase as
we hire additional research and development personnel to develop new products
and upgrade our existing ones.

CUSTOMERS

    Our target customers include Internet service providers and companies with
e-commerce sites and high-traffic Internet or intranet Web sites. We have also
participated in several high profile Web events. For example, BIG/ip and 3DNS
were used to manage traffic for the official shuttle.nasa.gov Web site for the
John Glenn space shuttle mission. This site featured a real-time audio and video
simulcast of the live NASA broadcast of the shuttle liftoff. In addition, video
clips covering the remainder of the mission were periodically updated and made
available through the site. On its most active day, this site received over 7
million user requests. We have sold our products directly or through resellers,
including Exodus

                                       32
<PAGE>
Communications and Frontier GlobalCenter, to over 600 end-customers as of August
31, 1999. Our largest reseller, Exodus Communications, accounted for 21.7% of
our net revenues for the nine months ended June 30, 1999. The following is a
list of customers that have purchased at least $100,000 of our products since
the end of March 1998:
<TABLE>
<CAPTION>
Resellers             -  Cabletron                          -  NTT
                      -  Exodus                             -  Planet Online
                      -  Frontier GlobalCenter              -  Vanstar
                      -  Extreme                            -  Technautics
<S>                   <C>                                   <C>
ISP/Web Hosting       -  Exodus                             -  StarMedia Network
                      -  MCI WorldCom                       -  UUNet
                      -  PSINet                             -  Verio

<CAPTION>
<S>                   <C>                                   <C>
Intranet/Enterprise   -  Activate                           -  Microsoft
                      -  BankAmerica                        -  Motorola
                      -  BellSouth                          -  Nanocosm
                      -  Cable & Wireless                   -  Network Solutions
                      -  Citigroup/Salomon Smith Barney     -  Next Venue
                      -  Digital Entertainment              -  Office.com
                      -  Encyclopedia Britannica            -  People's Bank
                      -  Fidelity Investments               -  ShopNow.com
                      -  First Data Corp                    -  Unum
                      -  Freddie Mac                        -  Zip2
                      -  ISPNews
</TABLE>

SALES AND MARKETING

    We market and sell our Internet traffic management solutions through a
direct sales force in the United States, the United Kingdom, the Netherlands and
Australia, as well as through domestic and international channel partners. We
plan to invest significant resources to expand our direct sales force and
further develop our indirect sales channels by developing relationships with
leading industry resellers, original equipment manufacturers, systems
integrators, Internet service providers and other channel partners. Typically,
our agreements with our channel partners are not exclusive and do not prevent
our channel partners from selling competitive products. These agreements
typically have terms of one or two years with no obligation to renew, and
typically do not provide for exclusive sales territories or minimum purchase
requirements.

    Exodus and Frontier GlobalCenter account for most of our indirect sales. We
are in the process of seeking channel partners for our products in the United
States and selected countries in the European and Asia Pacific markets. We have
increased, and plan to further increase, the number of individuals focused on
sales to government entities, and are developing strategic relationships that
will help facilitate these sales. As of August 31, 1999, we employed 67 people
in sales and marketing.

    Our regional sales managers are responsible for direct customer contact and
are located in Seattle, San Francisco, Los Angeles, Dallas, Chicago, Boston,
Detroit, New York, Atlanta, Washington, D.C., the United Kingdom, the
Netherlands and Australia. Our inside sales managers generate and qualify leads
for our regional sales managers and help manage accounts by serving as a liaison
between our field and internal corporate resources. Our field systems engineers
also support our regional sales managers by participating in joint sales calls
and providing pre-sales technical resources as needed.

    We plan to continue to build strong brand awareness to leverage the value of
our Internet traffic management products and professional services in the
marketplace. We believe brand visibility is a key factor in increasing customer
awareness, and our goal is for the F5 brand to be synonymous with superior

                                       33
<PAGE>
performance, high quality customer service and ease of use. We market our
products and services through a broad range of marketing programs, including
active tradeshow participation, advertising in print publications, direct
marketing, high-profile Web events and our Internet site. Our marketing programs
are focused on creating awareness of our Internet traffic management solutions
and services and are targeted at information technology professionals such as
chief information officers.

PROFESSIONAL SERVICES AND TECHNICAL SUPPORT

    We believe that our ability to consistently provide high-quality customer
service and support will be a key factor in attracting and retaining customers.
Prior to the installation of our Internet traffic management solutions, our
professional services team works with organizations to analyze and understand
their special network needs. They also make recommendations on how to integrate
our solutions to best utilize our product features and functionality to support
their unique network environment. Once our customers purchase our products, we
go on-site to help with installation and provide an initial training session to
help our customers make use of the functionality built into our products.

    Our technical support team provides remote support through a 24x7 help desk.
Our technical support team also assists our customers with online updates and
upgrades. We also offer seminars and training sessions for our customers on the
configuration and use of our products, including local and wide area network
system administration and management. In addition, we provide a full range of
consulting services to our customers, including comprehensive network
management, documentation and performance analysis and capacity planning to
assist in predicting future network requirements. As of August 31, 1999, our
professional services and technical support team consisted of 21 employees.

MANUFACTURING

    We outsource the manufacturing of our pre-configured, industry-standard
hardware platforms to primarily two contract manufacturers, Micro Standard
Distributors and Unisoft, who assemble these hardware platforms to our
specifications. These platforms consist primarily of an Intel-based computing
platform, rack-mounted enclosure system and custom-designed front panel. We
install our proprietary software onto the hardware platforms and conduct
functionality testing, quality assurance and documentation control prior to
shipping our products.

    We have experienced minor delays in shipments from these contract
manufacturers in the past which have not had a material impact on our results of
operations. We may experience delays in the future or other problems, such as
inferior quality and insufficient quantity of product, any of which may
seriously harm our business and results of operations. From time to time, we
intend to introduce new products and product enhancements, which will require
that we coordinate our efforts with those of our contract manufacturers to
ensure a sufficient quantity of hardware components. In addition, as our sales
increase our contract manufacturers will need to achieve volume production to
meet our demand. The inability of our contract manufacturers to provide us with
adequate supplies of high-quality hardware platforms or the loss of one or more
of our contract manufacturers may cause a delay in our ability to fulfill orders
while we obtain a replacement manufacturer and may seriously harm our business
and results of operations.

    Subcontractors supply our contract manufacturers with the standard parts and
components for our products. These standard hardware parts and components
consist of motherboards, reboot cards and chasses.

    Generally, purchase commitments with our limited source suppliers are on a
purchase order basis. An interruption or delay in the supply of any of these
hardware components, or the inability to procure these components from alternate
sources at acceptable prices and within a reasonable time, will seriously harm
our business and results of operations. In addition, qualifying additional
suppliers can be time-consuming and expensive and may increase the likelihood of
errors.

                                       34
<PAGE>
    Lead times for purchasing these components vary significantly and depend on
factors such as the specific supplier, contract terms and demand for a component
at a given time. If orders do not match forecasts, excess or inadequate supplies
of certain materials, including components manufactured by our subcontractors,
may seriously harm our business and results of operations.

COMPETITION

    Our markets are new, rapidly evolving and highly competitive, and we expect
this competition to persist and intensify in the future. We compete in the
Internet traffic management market primarily on the basis of price, service,
warranty and product performance. Our principal competitors in the Internet
traffic management market include Cisco Systems, Alteon WebSystems, ArrowPoint
Communications, HydraWeb Technologies, RadWare and Resonate. We expect to
continue to face additional competition as new participants enter the Internet
traffic management market. Companies with significant resources, brand
recognition and sales channels may form alliances with or acquire competing
Internet traffic management solutions and emerge as significant competitors. In
addition, competitors may bundle their products or incorporate an Internet
traffic management component into existing products in a manner that discourages
users from purchasing our products. Potential customers may also choose to
purchase additional servers instead of our products.

    Cisco Systems has a product offering similar to ours and holds the dominant
share of the market. Cisco has a longer operating history and significantly
greater financial, technical, marketing and other resources than we do. Cisco
also has a more extensive customer base and broader customer relationships
including relationships with many of our current and potential customers that
could be leveraged. In addition, Cisco has significantly more established
customer support and professional services organizations and more extensive
direct sales force and direct and indirect sales channels than we do. Cisco and
our other competitors may be able to respond more quickly to new or emerging
technologies and changes in customer requirements than we can. In addition,
these companies may adopt aggressive pricing policies to gain market share. As a
result, we may not be able to maintain a competitive position against current or
future competitors. Our failure to maintain and enhance our competitive position
within the market may seriously harm our business and results of operations.

INTELLECTUAL PROPERTY

    We rely on a combination of copyright, trademark and trade secret laws and
restrictions on disclosure to protect our intellectual property rights. We
currently do not have any issued patents but have four applications pending for
various aspects of our technology.

    We also enter into confidentiality or license agreements with our employees,
consultants and corporate partners, and control access to and distribution of
our software, documentation and other proprietary information. Despite our
efforts to protect our proprietary rights, unauthorized parties may attempt to
copy or otherwise obtain and use our products or technology. Monitoring
unauthorized use of our products is difficult, and we cannot be certain that the
steps we have taken will prevent misappropriation of our technology,
particularly in foreign countries where the laws may not protect our proprietary
rights as fully as in the United States. In addition, we have not entered into
non-competition agreements with several of our former employees.

    We incorporate software that is licensed from several third party sources
into our products. These licenses generally renew automatically on an annual
basis. We believe that alternative technologies for this licensed software are
available both domestically and internationally.

    From time to time, third parties may assert exclusive patent, copyright,
trademark and other intellectual property rights claims or initiate litigation
against us or our contract manufacturers, suppliers or customers with respect to
existing or future products. Although we have not been a party to any claims
alleging infringement of intellectual property rights, we cannot assure you that
we will not be subject to these claims

                                       35
<PAGE>
in the future. We may in the future initiate claims or litigation against third
parties for infringement of our proprietary rights to determine the scope and
validity of our proprietary rights or those of our competitors. Any of these
claims, with or without merit, may be time-consuming, result in costly
litigation and diversion of technical and management personnel or require us to
cease using infringing technology develop non-infringing technology or enter
into royalty or licensing agreements. Such royalty or licensing agreements, if
required, may not be available on acceptable terms, if at all. In the event of a
successful claim of infringement and our failure or inability to develop
non-infringing technology or license the infringed or similar technology on a
timely basis, our business and results of operations may be seriously harmed.

EMPLOYEES

    As of August 31, 1999, we employed 178 full-time persons, 57 of whom were
engaged in product development, 67 in sales and marketing, 21 in professional
services and technical support and 33 in finance, administration and operations.
None of our employees is represented by a labor union and we have not
experienced any work stoppages to date. We consider our employee relations to be
good.

FACILITIES

    We currently lease an aggregate of approximately 28,000 square feet of
office space in Seattle, Washington. The current lease for the Seattle facility
expires in February 2004, with an option to renew for five years. We have also
signed a lease for approximately 84,000 square feet of new office space in
Seattle in a building which is currently under construction. This lease will
commence on approximately July 1, 2000, and will expire 12 years after
commencement. We also lease office space for our sales personnel in New York,
California and the United Kingdom.

LEGAL PROCEEDINGS

    From time to time, we may be involved in litigation relating to claims
arising out of our ordinary course of business. We are not currently involved in
any material legal proceedings.

                                       36
<PAGE>
                                   MANAGEMENT

    THE FOLLOWING TABLE SETS FORTH CERTAIN INFORMATION WITH RESPECT TO OUR
EXECUTIVE OFFICERS AND DIRECTORS AS OF AUGUST 31, 1999:

EXECUTIVE OFFICERS AND DIRECTORS

<TABLE>
<CAPTION>
NAME                                                AGE POSITION
- --------------------------------------------------  --- --------------------------------------------------
<S>                                                 <C> <C>
Jeffrey S. Hussey.................................  38  Chairman of the Board, Chief Executive Officer and
                                                          President
Robert J. Chamberlain.............................  46  Vice President of Finance, Chief Financial Officer
                                                        and Treasurer
Steven Goldman....................................  39  Senior Vice President of Sales, Marketing and
                                                        Services
Brett L. Helsel...................................  39  Vice President of Product Development and Chief
                                                          Technology Officer
Carlton G. Amdahl (1).............................  47  Director
Karl D. Guelich (1)(2)............................  57  Director
Alan J. Higginson (2).............................  52  Director
Sonja L. Hoel (2).................................  33  Director
Kent L. Johnson (3)...............................  56  Director
</TABLE>

- ------------------------

(1) Member of Audit Committee.

(2) Member of Compensation Committee.

(3) Mr. Johnson has tendered his resignation as a director, effective October 5,
    1999.

    JEFFREY S. HUSSEY co-founded F5 in February 1996 and has been our Chairman,
Chief Executive Officer and President since that time. From February 1996 to
March 1999, Mr. Hussey also served as our Treasurer. From July 1995 to February
1996, Mr. Hussey served as Vice President of Alexander Hutton Capital L.L.C., an
investment banking firm. From September 1993 to July 1995, Mr. Hussey served as
President of Pacific Comlink, an inter-exchange carrier providing frame relay
and Internet access services to the Pacific Rim, which he founded in September
1993. Mr. Hussey holds a B.A. in Finance from Seattle Pacific University and an
M.B.A. from the University of Washington.

    ROBERT J. CHAMBERLAIN has served as our Vice President of Finance, Chief
Financial Officer and Treasurer since March 1999. From September 1998 to
February 1999, Mr. Chamberlain served as Senior Vice President and Chief
Financial Officer of Yesler Software, an early stage company developing a
personal multimedia web communication product. From February 1998 to July 1998,
Mr. Chamberlain served as Co-President of Photodisc, a provider of digital
imagery, which merged with Getty Images Inc. in February 1998. From May 1997 to
February 1998, Mr. Chamberlain served as Senior Vice President and Chief
Financial Officer of Photodisc. From April 1996 to May 1997, Mr. Chamberlain
served as Executive Vice President and Chief Financial Officer of Midcom
Communications Inc., a telecommunications service provider. From January 1992 to
December 1995, Mr. Chamberlain served as Vice President Finance and Operations
of ElseWare Corporation, a font technology company. From July 1989 to April
1991, Mr. Chamberlain was an audit partner in the high technology practice of
KPMG Peat Marwick, and was employed by KPMG Peat Marwick since January 1980. Mr.
Chamberlain holds a B.S. in Business Administration and Accounting from
California State University, Northridge.

    STEVEN GOLDMAN has served as our Vice President of Sales and Marketing since
July 1997 and our Senior Vice President of Sales, Marketing and Services since
July 1999. From December 1996 to February 1997, Mr. Goldman served as Vice
President, Enterprise Sales and Services, for Microtest, Inc., a network test
equipment and CD ROM server company, after its acquisition of Logicraft. From
March 1995 to December 1996, Mr. Goldman served as Executive Vice President,
North American Operations, for

                                       37
<PAGE>
Logicraft, a CD ROM server company, after its merger with Virtual Microsytems, a
CD ROM server company. From 1990 to March 1995, Mr. Goldman served as Vice
President of Sales for Virtual Microsystems. Mr. Goldman holds a B.A. in
Economics from the University of California at Berkeley.

    BRETT L. HELSEL has served as our Vice President of Product Development and
Chief Technology Officer since May 1998. From April to May 1998, Mr. Helsel
served as our Vice President of Advanced Product Architecture. From March 1997
to March 1998, Mr. Helsel served as Vice President, Product Development, for
Cybersafe, Inc., a provider of enterprise-wide network security solutions. From
April 1994 to October 1997, Mr. Helsel served as Site Development Manager for
Wall Data, a host connectivity software company. Mr. Helsel holds a B.S. in
Geophysics and Oceanography from the Florida Institute of Technology.

    CARLTON G. AMDAHL has served as one of our directors since May 1998. Mr.
Amdahl operates Amdahl Associates, a consulting firm specializing in technology
management, product strategy and system architecture. Mr. Amdahl has served as
President of Network Caching Technology L.L.C., a network caching company, since
February 1999 and as President and Chief Executive Officer of Inca Technology, a
network caching company, since October 1997. From 1985 to January 1996, Mr.
Amdahl served as Chairman of the board of directors and Chief Technical Officer
of NetFRAME Systems, a high performance network server company, which he founded
in 1985. Mr. Amdahl is a Stanford University Sloan Fellow and holds a B.S.
degree in Electrical Engineering and Computer Science from the University of
California, Berkeley and an M.S. in Management from Stanford University.

    KARL D. GUELICH has served as one of our directors since June 1999. Mr.
Guelich has been in private practice as a certified public accountant since his
retirement from Ernst & Young in 1993, where he served as the Area Managing
Partner for the Pacific Northwest offices headquartered in Seattle from October
1986 to November 1992. Mr. Guelich holds a B.S. degree in Accounting from
Arizona State University.

    ALAN J. HIGGINSON has served as one of our directors since May 1996. From
November 1995 to November 1998, Mr. Higginson served as President of Atrieva
Corporation, a provider of advanced data backup and retrieval technology. From
May 1990 to November 1995, Mr. Higginson served as Executive Vice President of
Worldwide Sales and Marketing for Sierra On-line, a developer of multimedia
software for the home personal computer market. From May 1990 to November 1995,
Mr. Higginson served as President of Sierra On-line's Bright Star division, a
developer of educational software. Mr. Higginson holds a B.S. in Commerce and an
M.B.A. from the University of Santa Clara.

    SONJA L. HOEL has served as one of our directors since August 1998. Ms. Hoel
has been a managing director and general partner of Menlo Ventures, a venture
capital firm, since July 1996 and has been employed by Menlo Ventures since July
1994. From August 1993 to April 1994, Ms. Hoel was an associate at the Edison
Venture Fund, a venture capital firm. From December 1991 to June 1993, Ms. Hoel
served as a business development consultant at Symantec Corporation, a consumer
software applications company, and from January 1989 to June 1991, served as an
investment analyst at TA Associates, a venture capital firm. Ms. Hoel holds a
B.S. in Commerce from the University of Virginia and an M.B.A from the Harvard
Business School.

    KENT L. JOHNSON has served as one of our directors since May 1996. Mr.
Johnson has tendered his resignation as a director of F5, effective October 5,
1999. Mr. Johnson is the Chairman and Managing Director of AHVP Management, LLC
which is the general partner of Alexander Hutton Venture Partners, a venture
capital fund. Prior to that Mr. Johnson served as President of Alexander Hutton
Capital, L.L.C., which he co-founded in August 1994. From April 1989 to May
1994, Mr. Johnson served as Senior Vice President and Chief Operating Officer of
Brazier Forest Industries, a forest products company. Mr. Johnson is also a
director of Timeline, Inc., a software company. Mr. Johnson holds a B.A. in
Business Administration from the University of Washington and an M.B.A. from
Seattle University.

                                       38
<PAGE>
    Our executive officers are appointed by the board of directors and serve
until their successors are elected or appointed.

    There are no family relationships among any of our directors or executive
officers.

BOARD COMPOSITION

    We have authorized a range of directors from five to nine. In accordance
with the terms of our amended articles of incorporation, the terms of office of
the board of directors is divided into three classes:

    - Class I directors, whose term expires at the annual meeting of
      shareholders to be held in 2000;

    - Class II directors, whose term expires at the annual meeting of
      shareholders to be held in 2001; and

    - Class III directors, whose term expires at the annual meeting of
      shareholders to be held in 2002.

    Our Class I directors are Mr. Guelich and Ms. Hoel, our Class II directors
are Messrs. Higginson and Johnson, and our Class III directors are Messrs.
Amdahl and Hussey. At each annual meeting of shareholders after the initial
classification, the successors to directors whose terms will then expire will be
elected to serve from the time of election and qualification until the third
annual meeting following election. Any additional directorships resulting from
an increase in the number of directors will be distributed among the three
classes so that, as nearly as possible, each class will consist of one-third of
the directors. This classification of the board of directors may have the effect
of delaying or preventing changes in control or management of F5.

BOARD COMMITTEES

    - AUDIT COMMITTEE. Our audit committee, consisting of Mr. Amdahl and Mr.
      Guelich, reviews our internal accounting procedures and consults with and
      reviews the services provided by our independent auditors.

    - COMPENSATION COMMITTEE. Our compensation committee, consisting of Ms. Hoel
      and Messrs. Higginson and Guelich, reviews and recommends to the board of
      directors the compensation and benefits of all our officers and
      establishes and reviews general policies relating to compensation and
      benefits of our employees. Mr. Hussey, who acts as a plan administrator
      for our 1998 Equity Incentive Plan, authorizes stock option grants for
      employees other than officer and director level employees within ranges
      pre-approved by the board of directors.

COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION

    None of our executive officers serves as a member of the board of directors
or compensation committee of any entity that has one or more executive officers
serving as a member of our board of directors or compensation committee.

DIRECTOR COMPENSATION

    Directors currently receive no cash compensation from F5 for their services
as members of the board of directors. They are reimbursed for certain expenses
in connection with attendance at board and committee meetings. From time to
time, certain non-employee directors have received grants of options to purchase
shares of our common stock. In May 1996, Messrs. Higginson and Johnson each were
granted an option to purchase 84,000 shares of our common stock at an exercise
price of $0.50 per share. In May 1998, Mr. Amdahl was granted an option to
purchase 84,000 shares of our common stock at an exercise price of $0.50 per
share. Eligible non-employee directors receive automatic option grants under our
1999 Non-Employee Directors' Option Plan at the fair market value of our common
stock on the date of grant. In June, 1999, Mr. Guelich was granted an option
under this plan to purchase 5,000 shares of our

                                       39
<PAGE>
common stock at an exercise price of $18.00 per share. See "--Equity Incentive
Plans--Amended and Restated Directors' Nonqualified Stock Option Plan" and
"--1999 Non-Employee Directors' Option Plan."

EXECUTIVE COMPENSATION

    The table below sets forth the compensation paid by us during the fiscal
year ended September 30, 1998 to (a) our President and Chief Executive Officer
and (b) our only other executive officer other than the Chief Executive Officer
whose salary and bonus for fiscal 1998 exceeded $100,000 and who served as an
executive officer of F5 during the fiscal year ended September 30, 1998.

                           SUMMARY COMPENSATION TABLE

<TABLE>
<CAPTION>
                                                    ANNUAL COMPENSATION
                                                    --------------------
NAME AND PRINCIPAL POSITION                          SALARY      BONUS    ALL OTHER COMPENSATION
- --------------------------------------------------  ---------  ---------  -----------------------
<S>                                                 <C>        <C>        <C>
Jeffrey S. Hussey.................................  $ 128,749  $   3,196                --
  President and Chief Executive Officer

Steven Goldman....................................    120,000      5,000         $  46,444(1)
  Senior Vice President of Sales, Marketing and
    Services
</TABLE>

- ------------------------

(1) Represents commissions paid to Mr. Goldman in fiscal 1998.

OPTION GRANTS IN LAST FISCAL YEAR

    We did not grant any options to the executive officers shown in the Summary
Compensation Table above in fiscal 1998.

FISCAL YEAR-END OPTION VALUES

    The following table sets forth for the executive officers shown in the
Summary Compensation Table the aggregate dollar value realized upon exercise of
stock options in the last fiscal year and number and value of securities
underlying unexercised options held at September 30, 1998.

<TABLE>
<CAPTION>
                                                                                               VALUE OF UNEXERCISED
                                                          NUMBER OF SECURITIES                IN-THE-MONEY OPTIONS AT
                                                     UNDERLYING UNEXERCISED OPTIONS         SEPTEMBER 30, 1998 ($) (1)
                                         VALUE           AT SEPTEMBER 30, 1998          -----------------------------------
                     SHARES ACQUIRED   REALIZED   ------------------------------------                      UNEXERCISABLE
NAME                 ON EXERCISE (#)    ($) (1)    EXERCISABLE (#)   UNEXERCISABLE (#)   EXERCISABLE ($)         ($)
- ------------------  -----------------  ---------  -----------------  -----------------  -----------------  ----------------
<S>                 <C>                <C>        <C>                <C>                <C>                <C>
Jeffrey S.
  Hussey..........             --             --             --                 --                 --                 --
Steven Goldman....         59,250      $ 589,538             --            177,750(2)              --         $1,768,613
</TABLE>

- --------------------------

(1) Based on the initial public offering price of $10.00 per share less the
    exercise price, multiplied by the number of shares underlying the option.

(2) These options vest 25% on each of the first, second, third and fourth
    anniversary of the grant date. These options will vest fully if we are
    acquired in a merger or asset sale. All of these options have a ten-year
    term.

INCENTIVE STOCK PLANS

    1998 EQUITY INCENTIVE PLAN.  Our board of directors adopted our 1998 Equity
Incentive Plan on October 22, 1998, and our shareholders approved it on November
12, 1998. We initially reserved a total of 800,000 shares for issuance under the
plan. In April 1999 we reserved an additional 1,500,000 shares for issuance
under the plan and the shareholders approved it in May, 1999. The plan provides
for grants of incentive stock options that qualify under Section 422 of the
Internal Revenue Code of 1986, as amended, to employees, including officers, of
F5 or any affiliate of F5, and nonstatutory stock options, restricted

                                       40
<PAGE>
stock purchase awards, and stock bonuses to employees, including officers, or
directors of and consultants to F5 or any affiliate of F5. The board or a
committee appointed by the board administers the plan. Our board has the
authority to determine which recipients and what types of awards are to be
granted, including the exercise price, number of shares subject to the award and
the exercisability of the awards.

    The term of a stock option granted under the plan generally may not exceed
10 years. The board of directors determines the exercise price of options
granted under the plan. However, in the case of an incentive stock option, the
exercise price cannot be less than 100% of the fair market value of our common
stock on the date of grant and, in the case of a nonstatutory stock option, the
exercise price cannot be less than 50% of the fair market value of our common
stock on the date of grant. Options granted under the plan vest at the rate
specified in the option agreement. Except as expressly provided by the terms of
a nonstatutory stock option agreement, an optionee may not transfer options
other than by will or the laws of descent or distribution, provided that an
optionee may designate a beneficiary who may exercise the option following the
optionee's death. An optionee whose relationship with us or any related
corporation ceases for any reason, except by death or permanent and total
disability, generally may exercise vested options up to three months following
cessation. Vested options may generally be exercised for up to 12 months after
an optionee's relationship with F5 or any affiliate of F5 ceases due to
disability and for generally up to 18 months after the relationship with F5 or
any affiliate of F5 ceases due to death. However, options may terminate or
expire sooner or later as may be determined by the board and set forth in the
option agreement.

    No incentive stock option may be granted to any person who, at the time of
the grant, owns, or is deemed to own, stock possessing more than 10% of the
total combined voting power of F5 or any affiliate of F5, unless the option
exercise price is at least 110% of the fair market value of the stock subject to
the option on the date of grant and the term of the option does not exceed five
years from the date of grant. In addition, the aggregate fair market value,
determined at the time of grant, of the shares of our common stock with respect
to which incentive stock options are exercisable for the first time by an
optionee during any calendar year under the plan and all other stock plans of F5
and its affiliates may not exceed $100,000. The options, or portions of the
options, which exceed this limit are treated as nonstatutory options.

    No person may be granted options under the plan covering an aggregate of
more than 200,000 shares of our common stock in any calendar year.

    Shares subject to stock awards that have lapsed or terminated, without
having been exercised in full, may again become available for the grant of
awards under the plan.

    Restricted stock purchase awards granted under the plan may be granted
pursuant to a repurchase option in our favor in accordance with a vesting
schedule determined by the board. The purchase price of these awards will be at
least 50% of the fair market value of our common stock on the date of grant.
Stock bonuses may be awarded in consideration for past services. Rights under a
stock bonus or restricted stock purchase agreement may not be transferred other
than by will or by the laws of descent and distribution unless the stock bonus
or restricted stock purchase agreement specifically provides for
transferability.

    Upon certain changes in control of F5 as provided under the plan, the
surviving entity will either assume or substitute all outstanding stock awards
under the plan. If the surviving entity determines not to assume or substitute
these awards, then with respect to persons whose service with F5 or an affiliate
of F5 has not terminated before the change in control, the vesting of 50% of
these stock awards (and the time during which these awards may be exercised)
will accelerate and the awards terminated if not exercised before the change in
control.

    As of August 31, 1999, we had issued 169,291 shares upon the exercise of
options granted under the plan and options to purchase 687,765 shares were
outstanding with 1,442,944 shares reserved for future grants or purchases under
the plan. The plan will terminate on October 21, 2008, unless terminated sooner
by the board.

                                       41
<PAGE>
    AMENDED AND RESTATED 1996 STOCK OPTION PLAN.  Our board of directors adopted
the Amended and
Restated 1996 Stock Option Plan on December 2, 1996, and our shareholders
approved it on January 28, 1997. We have reserved a total of 2,600,000 shares
for issuance under the plan, less any shares issuable upon the exercise of
options granted under the Amended and Restated Directors' Nonqualified Stock
Option Plan. The plan provides for grants of incentive stock options that
qualify under Section 422 of the Internal Revenue Code to employees, including
officers and employee directors, of F5 or any affiliate of F5 and nonstatutory
stock options to employees, consultants and other persons selected by the board.
The board or a committee appointed by the board administers the plan. The board
has the authority to determine which recipients and what types of options are to
be granted, including the exercise price, number of shares subject to the option
and the exercisability of the options.

    The term of a stock option granted under the plan generally may not exceed
10 years. The exercise price of incentive stock options and non-statutory stock
options granted under the plan following the offering, will not be less than
100% of the fair market value of our common stock on the date of grant. Options
granted under the plan vest at the rate specified in the option agreement,
provided that options will vest as to 25% of the underlying shares each year
following the date of grant if vesting is not specified in the option agreement.
An optionee may not transfer any options other than by will or the laws of
descent or distribution. If an optionee's service terminates due to death or
disability, then any option held by this optionee who F5 or an affiliate of F5
has continuously employed for two years will automatically become fully vested
and be exercisable for the duration of the option term.

    An optionee whose relationship with F5 or any affiliate of F5 ceases for any
reason, other than by death or permanent and total disability, may exercise
vested options up to 90 days following the cessation or a longer period as may
be extended by the board in the case of a nonstatutory stock option. Options may
be exercised for up to 12 months after an optionee's relationship with F5 or its
affiliate ceases due to death or disability or a longer period as the board of
directors may extend in the case of a nonstatutory stock option.

    No incentive stock option may be granted to any person who, at the time of
the grant, owns, or is deemed to own, stock possessing more than 10% of the
total combined voting power of F5 or any affiliate of F5, unless the option
exercise price is at least 110% of the fair market value of the stock subject to
the option on the date of grant and the term of the option does not exceed five
years from the date of grant. In addition, the aggregate fair market value,
determined at the time of grant, of the shares of our common stock with respect
to which incentive stock options are exercisable for the first time by an
optionee during any calendar year under the plan and all other stock plans of F5
and its affiliates may not exceed $100,000. The options, or portions of the
options, which exceed this limit are treated as nonstatutory options.

    Shares subject to stock options that have lapsed or terminated, without
having been exercised in full, may again become available for the grant of
options under the plan.

    Upon certain changes of control of F5 as provided under the plan, or in the
case of a dividend in excess of 10% of the then fair market value of our stock,
all outstanding options will automatically become fully vested and exercisable
for the duration of the option term.

    As of August 31, 1999, we had issued 623,750 shares upon the exercise of
options granted under the plan and options to purchase 1,579,640 shares were
outstanding with 102,610 shares reserved for future
grants under either this plan or our Amended and Restated Directors'
Nonqualified Stock Option Plan. We do not plan to grant any additional options
under this plan.

    AMENDED AND RESTATED DIRECTORS' NONQUALIFIED STOCK OPTION PLAN.  Our board
of directors adopted the Amended and Restated Directors' Nonqualified Stock
Option Plan on December 2, 1996, and our shareholders approved it on January 28,
1997. The plan provides for the issuance of up to 2,600,000 shares of our common
stock, less the number of any shares issuable upon exercise under the Amended
and Restated 1996 Stock Option Plan. All of our non-employee directors who
joined our board of directors

                                       42
<PAGE>
before August 21, 1998 were entitled to receive non-discretionary stock option
grants under the plan. Options granted under the plan do not qualify as
incentive stock options under the Internal Revenue Code. Each option granted
pursuant to the plan has an exercise price equal to $0.50. Under the plan, each
non-employee director who joined the board following the closing of the offering
of our Series A preferred stock and before May 1, 1998 and who was not elected
in direct connection with his or her investment in our stock (or with the
investment in our stock by an affiliated or representative entity of the
non-employee director) was automatically granted an option to purchase that
number of shares of our common stock equal to one percent of the then-current
fully-diluted number of shares of our common stock. After May 1, 1998, each
newly appointed non-employee director was automatically granted an option to
purchase 84,000 shares of our common stock. Options granted under the plan vest
in three equal annual installments from the date of grant and become immediately
vested and exercisable upon a director's death or disability. Options granted
under the plan are generally non-transferable. An optionee whose directorship
with F5 ceases for any reason, other than by death or disability, may exercise
vested options up to 90 days following cessation, unless these options terminate
or expire sooner by their terms. Options may be exercised for up to one year
after an optionee's directorship with F5 ceases due to disability or death. An
optionee may not exercise any options granted under the plan, however, after the
expiration of ten years from the date it was granted. Upon certain changes of
control of F5 as provided under the plan, the plan's options will automatically
become fully vested and be exercisable for the duration of the option term.

    As of August 31, 1999, we had issued 126,000 shares upon the exercise of
options granted under the plan, and options to purchase 168,000 shares were
outstanding with 102,610 shares reserved for future grants or purchases under
either this plan or the 1996 Stock Option Plan. We do not plan to grant any
additional options under the Amended and Restated Directors' Nonqualified Stock
Option Plan.

    1999 NON-EMPLOYEE DIRECTORS' STOCK OPTION PLAN.  We adopted the 1999
Non-Employee Directors' Stock Option Plan in April 1999 to provide for the
automatic grant to F5 non-employee directors of options to purchase shares of
our common stock. The board administers the plan and cannot delegate
administration to a committee. In April 1999, we reserved an aggregate of
100,000 shares of common stock for issuance under the plan, subject to
adjustment in the event of certain capital changes, and the shareholders
approved it in May, 1999.

    Each person who is first elected or appointed as a non-employee director
after the initial public offering will automatically receive a fully vested and
exercisable option for 5,000 shares. In addition, on the day after each of our
annual meetings of the shareholders, starting with the annual meeting in 2000,
each eligible non-employee director will automatically receive a fully vested
and exercisable option for 5,000 shares, provided that the recipient has been a
non-employee director for at least the prior six months. As long as a
non-employee director who is an optionholder continues to serve with us or with
an affiliate of ours, whether in the capacity of a director, an employee or a
consultant, the optionholder may exercise the option.

    The optionholder may not transfer the option except by will or by the laws
of descent and distribution. Although only the optionholder may exercise the
option during his or her lifetime, the optionholder may designate a third party
who may exercise the option in the event of the optionee's death. Options
granted under the plan expire 10 years after the date of grant and have an
exercise price equal to 100% of the fair market value of the common stock on the
date of grant. If the optionholder's service to F5 or an affiliate terminates,
the optionholder may exercise the option for 12 months if termination is due to
disability, for 18 months if termination is due to death or for three months in
all other circumstances.

    In the event of a "change in control," the surviving or acquiring
corporation may assume outstanding options under the plan or substitute similar
options. A "change in control" means a sale of all or substantially all of F5's
assets, a merger or consolidation in which F5 is not the surviving corporation
or a reverse merger in which F5 is the surviving corporation but the shares of
common stock outstanding immediately preceding the merger are converted by
virtue of the merger into other property.

                                       43
<PAGE>
    As of August 31, 1999, an option to purchase 5,000 shares was outstanding
and 95,000 shares were reserved for future grants.

    1999 EMPLOYEE STOCK PURCHASE PLAN.  In April 1999, we adopted the 1999
Employee Stock Purchase Plan, authorizing the issuance of 1,000,000 shares of
common stock pursuant to purchase rights granted to employees of F5 or to
employees of any designated affiliate of F5 and the shareholders approved it in
May, 1999. The purchase plan is intended to qualify as an employee stock
purchase plan within the meaning of Section 423 of the Internal Revenue Code.

    The purchase plan provides a means by which employees may purchase our
common stock through payroll deductions. We implement this purchase plan by
offerings of purchase rights to eligible employees. Under the purchase plan, we
may specify offerings with a duration of not more than 27 months, and may
specify shorter purchase periods within each offering. The first offering began
on June 4, 1999. Unless otherwise determined by the board of directors, common
stock is purchased for accounts of employees participating in the purchase plan
at a price per share equal to the lower of (1) 85% of the fair market value of a
share of common stock on the first day of the offering or (2) 85% of the fair
market value of a share of common stock on the date of purchase.

    Generally, employees who work at least 20 hours per week and 5 months per
calendar year may deduct up to 15% of their base compensation for the purchase
of stock under the purchase plan. Employees may end their participation in the
offering at any time up to one day before the offering ends. Participation ends
automatically on termination of employment with F5 or an affiliate.

    We may grant eligible employees purchase rights under this plan only if the
rights together with any other rights granted under other employee stock
purchase plans established by F5 or an affiliate of F5, if any, do not permit
the employee's rights to purchase our stock to accrue at a rate which exceeds
$25,000 of fair market value of this stock for each calendar year in which these
rights are outstanding. No employee is eligible for the grant of any rights
under the purchase plan if immediately after we grant these rights, the employee
has voting power over 5% or more of our outstanding capital stock. As of the
date hereof, no shares of common stock had been purchased under the purchase
plan.

    401(k) PLAN.  We have adopted a tax-qualified employee savings and
retirement plan, the 401(k) Plan, for eligible United States employees. Eligible
employees may elect to defer a percentage of their eligible compensation in the
401(k) Plan, subject to the statutorily prescribed annual limit. We may make
matching contributions on behalf of all participants in the 401(k) Plan in an
amount determined by our board of directors. We may also make additional
discretionary profit sharing contributions in amounts as determined by the board
of directors, subject to statutory limitations. Matching and profit-sharing
contributions, if any, are subject to a vesting schedule; all other
contributions are at all times fully vested. We intend the 401(k) Plan, and the
accompanying trust, to qualify under Sections 401(k) and 501 of the Internal
Revenue Code so that contributions by employees or by F5 to the 401(k) Plan, and
income earned (if any) on plan contributions, are not taxable to employees until
withdrawn from the 401(k) Plan, and so that we will be able to deduct our
contributions, if any, 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.

LIMITATIONS OF LIABILITY AND INDEMNIFICATION MATTERS

    Our articles of incorporation limit the liability of directors to the
fullest extent permitted by the Washington Business Corporation Act as it
currently exists. Consequently, subject to the Washington Business Corporation
Act, no director will be personally liable to us or our shareholders for
monetary damages resulting from his or her conduct as a director of F5, except
liability for:

    - acts or omissions involving intentional misconduct or knowing violations
      of law;

    - unlawful distributions; or

                                       44
<PAGE>
    - transactions from which the director personally receives a benefit in
      money, property or services to which the director is not legally entitled.

    Our articles of incorporation provide that we may indemnify any individual
made a party to a proceeding because that individual is or was an F5 director or
officer, and this right to indemnification will continue as to an individual who
has ceased to be a director or officer and will inure to the benefit of his or
her heirs, executors or administrators. Any repeal of or modification to our
articles of incorporation may not adversely affect any right of an F5 director
or officer who is or was a director or officer at the time of any repeal or
modification. To the extent the provisions of our articles of incorporation
provide for indemnification of directors or officers for liabilities arising
under the Securities Act of 1933, as amended, those provisions are, in the
opinion or the Securities and Exchange Commission, against public policy as
expressed in the Securities Act and they are therefore unenforceable.

    Our bylaws provide that we will indemnify our directors and officers and may
indemnify our other officers and employees and other agents to the fullest
extent permitted by law.

    We have entered into agreements to indemnify our directors and certain
officers, in addition to indemnification provided for in our articles of
incorporation or bylaws. These agreements, among other things, indemnify our
directors and certain officers for certain expenses, including attorneys' fees,
judgments, fines and settlement amounts incurred by any of these persons in any
action or proceeding, including any action by us arising out of the person's
services as our director or officer or any other company or enterprise to which
the person provides services at our request. We believe that these provisions
and agreements are necessary to attract and retain qualified persons as
directors and officers. We also currently maintain liability insurance for our
officers and directors.

CHANGE OF CONTROL ARRANGEMENTS

    Upon certain changes in control of F5 as provided under the 1998 Equity
Incentive Plan, all outstanding stock awards under this plan will either be
assumed or substituted by the surviving entity. If the surviving entity
determines not to assume or substitute these awards, then with respect to
persons whose service with F5 or an affiliate of F5 has not terminated before
the change in control, the vesting of 50% of these stock awards and the time
during which these awards may be exercised will be accelerated and the awards
terminated if not exercised before the change in control.

    Upon certain changes of control of F5 as provided under the Amended and
Restated 1996 Stock Option Plan, or in the case of a dividend in excess of 10%
of the then fair market value of our stock, then all outstanding options under
this plan will automatically become fully vested and exercisable for the
duration of the option term.

    Upon certain changes of control of F5 as provided under the Amended and
Restated Directors' Nonqualified Stock Option Plan, all outstanding options will
automatically become fully vested and be exercisable for the duration of the
option term.

    Pursuant to the terms of an agreement between F5 and Mr. Goldman, in the
event of a business combination in which F5 is not the surviving entity, if the
surviving entity terminates Mr. Goldman as Senior Vice President of Sales,
Marketing and Services or changes his position to one that is not equal or
greater in scope, responsibility, compensation or stature, then Mr. Goldman may
be entitled to a severance payment equal to his 1998 compensation.

                                       45
<PAGE>
                              CERTAIN TRANSACTIONS

    Since our incorporation in February 1996 through August 31, 1999, we have
issued and sold securities to the following persons who are our executive
officers, directors or principal shareholders.

<TABLE>
<CAPTION>
                            SERIES A     SERIES B     SERIES C     SERIES D
                            PREFERRED    PREFERRED    PREFERRED    PREFERRED    WARRANTS     COMMON
INVESTOR (1)                STOCK (2)    STOCK (3)    STOCK (4)    STOCK (5)       (6)        STOCK
- -------------------------  -----------  -----------  -----------  -----------  -----------  ---------
<S>                        <C>          <C>          <C>          <C>          <C>          <C>
Carlton G. Amdahl........          --           --           --           --           --      28,000
Robert J. Chamberlain....          --           --           --           --           --     150,000
Steven Goldman...........          --           --           --           --           --      92,250
Brett Helsel.............          --           --           --           --           --      50,000
Alan J. Higginson........      10,000           --           --           --           --          --
Jeffrey S. Hussey........          --           --           --           --           --   3,448,000
Kent L. Johnson..........      10,000(7)         --          --           --           --      56,000
Michael D. Almquist......          --           --           --           --           --   1,480,000
Britannia Holdings
  Limited................          --      937,500           --           --    1,825,000     600,000
Cypress Partners Limited
  Partnership............          --           --      156,250           --           --     187,500
Encompass Group
  Incorporated...........     100,000      156,250           --           --      187,500          --
Menlo Ventures (8).......          --           --           --      843,926           --          --
Alexander Hutton Capital,
  L.L.C. (9).............          --           --           --           --           --     240,000
</TABLE>

- ------------------------

 (1) See "Principal and Selling Shareholders" for more detail on shares held by
     these purchasers.

 (2) The per share purchase price for our Series A preferred stock was $3.00.
     Each outstanding share of Series A preferred stock has been converted into
     six shares of common stock at a conversion price of $0.50 per share.

 (3) The per share purchase price for our Series B preferred stock was $1.60.
     Each outstanding share of Series B preferred stock has been converted into
     two shares of common stock at a conversion price of $0.80 per share.

 (4) The per share purchase price for our Series C preferred stock was $9.60.
     Each outstanding share of Series C preferred stock has been converted into
     six shares of common stock at a conversion price of $1.60 per share.

 (5) The per share purchase price for our Series D preferred stock was $6.79.
     Each outstanding share of Series D preferred stock has been converted into
     two shares of common stock at a conversion price of $3.395 per share.

 (6) Warrants are exercisable for our common stock at purchase prices per share
     as follows:

<TABLE>
<CAPTION>
WARRANTS                                                                                  PRICE
- --------------------------------------------------------------------------------------  ---------
<S>                                                                                     <C>
 600,000..............................................................................  $    0.50
 100,000..............................................................................  $    0.64
1,312,500.............................................................................  $    0.80
</TABLE>

 (7) Consists of 10,000 shares held by KLJ Ventures, of which Mr. Johnson is
     President.

 (8) The shares listed represent 809,910 shares held by Menlo Ventures VII, L.P.
     and 34,016 shares held by Menlo Entrepreneurs Fund VII, L.P. Ms. Hoel, one
     of our directors, is a managing director and general partner of Menlo
     Ventures.

 (9) Mr. Johnson, one of our directors, is President of Alexander Hutton
     Capital, L.L.C.

                                       46
<PAGE>
    In addition, we have granted options to certain of our executive officers.
See "Management-- Executive Compensation."

    In May, August and December 1996, we sold an aggregate of 400,000 shares of
Series A Preferred stock to certain investors, including Messrs. Higginson and
Johnson, two of our directors, members of the Hussey family, and Encompass Group
Limited, one of our principal shareholders, at an aggregate purchase price of
$1.2 million or $3.00 per share. We paid Alexander Hutton Capital, L.L.C. a
placement agent fee of $70,000 in connection with the sale of our Series A
preferred stock. Mr. Johnson, one of our directors, is President of Alexander
Hutton Capital, L.L.C.

    In March and August of 1997, we issued Brittania Holdings a warrant
exercisable for 100,000 and 600,000 shares of common stock in conjunction with
convertible note agreements of $500,000 and $300,000, respectively. The warrants
have per share exercise prices of $0.64 and $0.50, respectively.

    In September, October and November 1997, we sold an aggregate of 1,250,000
shares of Series B preferred stock to certain investors, including Brittania
Holdings and Encompass Group Limited, two of our principal shareholders, at an
aggregate purchase price of $2.0 million or $1.60 per share. We also issued
Brittania Holdings a warrant exercisable for 1,125,000 shares of common stock at
a per share exercise price of $0.80 and Encompass Group Limited a warrant
exercisable for 187,500 shares of common stock at a per share exercise price of
$0.80.

    On April 15, 1998, we sold an aggregate of 156,250 shares of Series C
preferred stock to Cypress Partners Limited Partnership at an aggregate purchase
price of $1.5 million or $9.60 per share, and issued Cypress Partners Limited
Partnership a warrant exercisable for 187,500 shares of common stock at a per
share exercise price of $1.60, which was exercised on February 1, 1999.

    On August 21, 1998, we sold an aggregate of 1,138,438 shares of Series D
preferred stock to certain investors, including affiliates of Menlo Ventures and
IDG Ventures, two of our principal shareholders, at an aggregate purchase price
of $7.7 million or $6.79 per share. Ms. Hoel, one of our directors, is a
managing director and general partner of Menlo Ventures.

    In March 1999, we issued 150,000 shares of our common stock to Mr.
Chamberlain in exchange for a promissory note. These shares were acquired by
exercising stock options that vest over a period of four years. The note bears
interest at a rate of 4.83%, is collateralized by the shares and partially
guaranteed by Mr. Chamberlain and is due in 2003. Under the pledge agreement, we
have the obligation to repurchase any remaining unvested shares, and the note
becomes due upon Mr. Chamberlain's termination. Further, the shares may not be
transferred until they are vested and paid for except under certain
circumstances as provided under the pledge agreement.

    We have entered into indemnification agreements with our directors and
certain officers for the indemnification of and advancement of expenses to these
persons to the fullest extent permitted by law. We also intend to enter into
these agreements with our future directors and certain officers.

    We believe that the foregoing transactions were in our best interest and
were made on terms no less favorable to us than could have been obtained from
unaffiliated third parties. All future transactions between us and any of our
officers, directors or principal shareholders will be approved by a majority of
the independent and disinterested members of the board of directors, will be on
terms no less favorable to us than could be obtained from unaffiliated third
parties and will be in connection with our bona fide business purposes.

                                       47
<PAGE>
                       PRINCIPAL AND SELLING SHAREHOLDERS

    The following table summarizes certain information regarding the beneficial
ownership of our outstanding common stock as of August 31, 1999 for:

    - each person or group that we know owns more than 5% of the common stock;

    - each of our directors;

    - our chief executive officer;

    - executive officers whose compensation exceeded $100,000 in 1998;

    - a shareholder who is selling shares in this offering; and

    - all of our directors and executive officers as a group.

<TABLE>
<CAPTION>
                                                               SHARES BENEFICIALLY
                                                                  OWNED PRIOR TO                       SHARES BENEFICIALLY
                                                                     OFFERING           NUMBER OF      OWNED AFTER OFFERING
                                                              ----------------------   SHARES BEING   ----------------------
NAME AND ADDRESS (1)                                           NUMBER    PERCENT (2)     OFFERED       NUMBER    PERCENT (2)
- ------------------------------------------------------------  ---------  -----------   ------------   ---------  -----------
<S>                                                           <C>        <C>           <C>            <C>        <C>
5% SHAREHOLDERS
Michael D. Almquist (3) ....................................  1,340,000       7.4%      300,000       1,040,000      5.6%
  153 Highland Drive
  Seattle, Washington 98109
Britannia Holdings Limited (4) .............................  3,950,000      19.8       800,000       3,150,000     15.4
  P.O. Box 556
  Main Street
  Charlestown, Nevis
Menlo Ventures VII, L.P. (5) ...............................  1,687,852       9.3       250,000       1,437,852      7.7
  3000 Sand Hill Rd., Bldg. 4-100
  Menlo Park, California 94025
Cypress Partners Limited Partnership .......................  1,125,000       6.2            --       1,125,000      6.0
  P.O. Box 9006
  Seattle, Washington 98109
Encompass Ventures, Inc. (6) ...............................  1,100,000       6.0            --       1,100,000      5.8
  777 - 108th Avenue N.E., Suite 2300
  Bellevue, Washington 98004
CURRENT EXECUTIVE OFFICERS AND DIRECTORS
Jeffrey S. Hussey (7).......................................  2,568,000      14.2       100,000       2,468,000     13.2
Steven Goldman (8)..........................................    206,110       1.1        40,000         166,110     *
Carlton G. Amdahl...........................................     28,000     *                --          28,000     *
Karl D. Guelich (9).........................................      5,000     *                --           5,000     *
Alan J. Higginson (10)......................................    141,300     *                --         141,300     *
Sonja L. Hoel (5)...........................................  1,687,852       9.3       250,000       1,437,852      7.7
Kent L. Johnson (11)........................................    170,740     *                --         170,740     *
All directors and executive officers as a group (9 persons)
  (12)......................................................  5,063,410      27.5       420,000       4,643,410     24.6
OTHER SELLING SHAREHOLDERS
Brian R. Dixon (13).........................................    150,908     *            20,000         130,908     *
Brett L. Helsel (14)........................................    106,408     *            30,000          76,408     *
Hussey Family Trust.........................................    400,000       2.2        50,000         350,000      1.9
Becky Arnett Hussey.........................................    350,000       1.9        35,000         315,000      1.7
Gerald W. Hussey and Helen J. Hussey........................    140,000     *            20,000         120,000     *
Gary Pittman (15)...........................................    500,000       2.7        50,000         450,000      2.4
Joann M. Reiter (16)........................................     18,600     *             5,000          13,600     *
</TABLE>

- --------------------------

   * Less than 1%

                                       48
<PAGE>
  (1) Unless otherwise indicated, the address of each of the named individuals
      is c/o F5 Networks, Inc., 200 First Avenue West, Suite 500, Seattle,
      Washington 98119

  (2) Beneficial ownership of shares is determined in accordance with the rules
      of the Securities and Exchange Commission and generally includes any
      shares over which a person exercises sole or shared voting or investment
      power, or of which a person has the right to acquire ownership at any time
      within 60 days after August 31, 1999. Except as otherwise indicated, and
      subject to applicable community property laws, the persons named in the
      table have sole voting and investment power with respect to all shares of
      common stock held by them. Applicable percentage ownership in the
      following table is based on 18,126,667 shares of common stock outstanding
      as of August 31, 1999 and 18,626,667 shares of common stock outstanding
      immediately following the completion of this offering assuming no options
      or warrants have been exercised since August 31, 1999.

  (3) Mr. Almquist co-founded our company in February 1996 and served as our
      Chief Technical Officer until February 1998.

  (4) The Duvall Trust is the sole shareholder of Britannia Holdings Limited.
      The Elfin Trust Company Limited, a Guernsey corporation, is the trustee of
      the Duvall Trust. Mr. Peter Howe is the trustee for the Elfin Trust
      Company Limited. Includes 1,825,000 shares issuable upon exercise of
      warrants exercisable within 60 days of August 31, 1999.

  (5) Ms. Hoel is a managing director and general partner of Menlo Ventures. The
      shares listed as beneficially owned prior to the offering represent
      1,619,820 shares held by Menlo Ventures VII, L.P. and 68,032 shares held
      by Menlo Entrepreneurs Fund VII, L.P. The number of shares being offered
      and the number of shares beneficially owned after offering reflect 239,923
      shares being offered by Menlo Ventures VII L.P. and 10,077 shares being
      offered by Menlo Entrepreneurs Fund VII, L.P. Ms. Hoel disclaims
      beneficial ownership of all shares held by Menlo Entrepreneurs Fund VII,
      L.P. except to the extent of her pro rata interest in this partnership.
      Ms. Hoel has served as one of our directors since August 1998.

  (6) Includes 187,500 shares issuable upon warrants exercisable within 60 days
      of August 31, 1999.

  (7) Does not include 400,000 shares held by Brian Dixon as trustee of the
      Hussey Family Trust fbo Mr. Hussey's minor child and 48,000 shares
      transferred to Mr. Hussey's brother in May 1999. Mr. Hussey co-founded our
      company in February 1996 and since then has served as our Chairman, Chief
      Executive Officer and President. From February 1996 until March 1999, Mr.
      Hussey also served as our treasurer.

  (8) Includes 113,860 shares issuable upon exercise of options exercisable
      within 60 days of August 31, 1999. Mr. Goldman served as our Vice
      President of Sales and Marketing from July 1997 until July 1999 and is
      currently serving as our Senior Vice President of Sales, Marketing and
      Services.

  (9) Includes 5,000 shares issuable upon exercise of options exercisable within
      60 days of August 31, 1999.

 (10) Includes 84,000 shares issuable upon exercise of options exercisable
      within 60 days of August 31, 1999.

 (11) Includes 28,000 shares issuable upon exercise of options exercisable
      within 60 days of August 31, 1999.

 (12) Includes 150,000 shares subject to repurchase by F5 and 287,268 shares
      issuable upon exercise of options exercisable within 60 days of August 31,
      1999.

 (13) Includes 8,408 shares issuable upon exercise of options exercisable within
      60 days of August 31, 1999 but does not include 400,000 shares held as
      trustee of the Hussey Family Trust fbo Mr. Hussey's minor child. Mr. Dixon
      served as our Vice President of Finance and Operations from June 1996 to
      March 1999, our Vice President of Operations from March 1999 to August
      1999 and is currently serving as our Director of Facilities.

 (14) Includes 56,408 shares issuable upon exercise of options exercisable
      within 60 days of August 31, 1999. Does not include 100 shares owned by
      Mr. Helsel's minor children. Mr. Helsel served as our Vice President of
      Advanced Product Architecture from April to May 1998 and is currently
      serving as our Vice President of Product Development.

 (15) Includes 187,500 shares issuable upon exercise of warrants exercisable
      within 60 days of August 31, 1999.

 (16) Includes 5,000 shares issuable upon exercise of options exercisable within
      60 days of August 31, 1999. Ms. Reiter has served as our General Counsel
      and Corporate Secretary since April 1998.

                                       49
<PAGE>
                          DESCRIPTION OF CAPITAL STOCK

GENERAL

    We have authorized 100,000,000 shares of common stock, no par value, and
10,000,000 shares of undesignated preferred stock, no par value. The following
description of our capital stock does not purport to be complete and is subject
to and qualified in its entirety by our second amended and restated articles of
incorporation and bylaws and by the provisions of applicable Washington law.

COMMON STOCK

    As of August 31, 1999, there were 18,126,667 shares of common stock
outstanding, which were held by 170 shareholders. Holders of common stock are
entitled to one vote per share on all matters to be voted upon by the
shareholders. Holders of common stock do not have cumulative voting rights, and,
therefore, holders of a majority of the shares voting for the election of
directors will be able to elect all of the directors.

    Holders of common stock will receive such dividends as our board of
directors may declare from time to time out of funds legally available for the
payment of dividends, subject to the terms of any existing or future agreements
between us and our debtholders. See "Dividend Policy." In the event of the
liquidation, dissolution or winding up of F5, the holders of common stock will
share ratably in all assets legally available for distribution after payment of
all debts and other liabilities and subject to the prior rights of any holders
of preferred stock then outstanding. Holders of our common stock have no
preemptive rights and no right to convert their common stock into any other
securities. There are no redemption or sinking fund provisions applicable to the
common stock. All outstanding shares of common stock are, and all shares of
common stock to be outstanding upon completion of this offering will be, fully
paid and nonassessable.

PREFERRED STOCK

    We have authorized 10,000,000 shares of undesignated preferred stock. There
are no shares of preferred stock outstanding. The board of directors has the
authority to issue the preferred stock in one or more series and to fix the
price, rights, preferences, privileges and restrictions thereof, including
dividend rights, dividend rates, conversion rights, voting rights, terms of
redemption, redemption prices, liquidation preferences and the number of shares
constituting a series or the designation of the series, without any further vote
or action by our shareholders. The issuance of preferred stock, while providing
desirable flexibility in connection with possible acquisitions and other
corporate purposes, could have the effect of delaying, deferring or preventing a
change in control of F5 without further action by the shareholders and may
adversely affect the market price of, and the voting and other rights of, the
holders of common stock. The issuance of preferred stock with voting and
conversion rights may adversely affect the voting power of the holders of common
stock, including the loss of voting control to others. We have no current plans
to issue any shares of preferred stock.

WARRANTS

    As of August 31, 1999, warrants to purchase 2,212,500 shares of common stock
were outstanding at a weighted-average exercise price of $0.75 per share.
Warrants exercisable for an aggregate 1,512,500 shares contain provisions for
the adjustment of the exercise price and the aggregate number of shares issuable
upon the exercise of the warrants in the event of stock dividends, stock splits,
reorganizations, reclassifications and consolidations. A warrant exercisable for
an aggregate of 12,500 shares of common stock contains additional provisions for
the adjustment of the exercise price and the aggregate number of shares issuable
upon certain dilutive issuances of securities at prices below the then existing
warrant exercise price.

                                       50
<PAGE>
REGISTRATION RIGHTS

    Holders of 5,364,376 shares of common stock and of warrants exercisable for
2,200,000 shares of common stock have certain rights relating to the
registration of these shares under state and federal securities laws. These
rights, which are assignable, are outlined in an agreement between F5 and these
holders. A majority of these holders may generally require that we register the
common stock subject to these rights for public resale provided that the
proposed aggregate selling offering price would exceed $5.0 million. If we
register any of our common stock either for our own account or for the account
of other security holders, these holders may also include their common stock
subject to these rights in the registration, subject to the ability of the
underwriters to limit the number of shares included in the offering. The holders
of our common stock that was issued upon conversion of our Series D preferred
stock may also require us to register all or a portion of their common stock
subject to these rights on Form S-3, when use of this form becomes available,
provided that among other limitations, the proposed aggregate offering price
would be at least $2.0 million. The registration rights of a holder terminates,
when the holder can, within a three month period, offer and sell all of his or
her registrable securities pursuant to Rule 144 and as to all holders, on June
4, 2002.

ANTI-TAKEOVER EFFECTS OF CERTAIN PROVISIONS OF AMENDED ARTICLES OF
  INCORPORATION, BYLAWS AND WASHINGTON LAW

    Our board of directors, without shareholder approval, has authority under
our amended articles of incorporation to issue preferred stock with rights
superior to the rights of the holders of common stock. As a result, our board
could issue preferred stock quickly and easily, which could adversely affect the
rights of holders of common stock and which our board could issue with terms
calculated to delay or prevent a change in control of F5 or make removal of
management more difficult.

    ELECTION AND REMOVAL OF DIRECTORS.  Our articles of incorporation provide
for the division of our board of directors into three classes, as nearly as
equal in number as possible, with the directors in each class serving for a
three-year term, and one class being elected each year by our shareholders. The
Class I term will expire at the annual meeting of shareholders to be held in
2000; the Class II term will expire at the annual meeting of shareholders to be
held in 2001; and the Class III term will expire at the annual meeting of
shareholders to be held in 2002. At each annual meeting of shareholders after
the initial classification, the successors to directors whose terms will then
expire will be elected to serve from the time of election and qualification
until the third annual meeting following election. Because this system of
electing and removing directors generally makes it more difficult for
shareholders to replace a majority of the board of directors, it may discourage
a third party from making a tender offer or otherwise attempting to gain control
of F5 and may maintain the incumbency of the board of directors.

    SHAREHOLDER MEETINGS.  Our bylaws provide that, except as otherwise required
by law or by our amended articles of incorporation, special meetings of the
shareholders can only be called pursuant to a resolution adopted by our board of
directors, the chairman of the board or president. These provisions of our
amended articles of incorporation and bylaws could discourage potential
acquisition proposals and could delay or prevent a change in control. These
provisions are intended to enhance the likelihood of continuity and stability in
the composition of the board of directors and in the policies formulated by the
board of directors and to discourage certain types of transactions that may
involve an actual or threatened change of control. These provisions are designed
to reduce our vulnerability to an unsolicited acquisition proposal. The
provisions also are intended to discourage certain tactics that may be used in
proxy fights. However, these provisions could have the effect of discouraging
others from making tender offers for our shares and, as a consequence, they also
may inhibit fluctuations in the market price of our shares that could result
from actual or rumored takeover attempts. Such provisions also may have the
effect of preventing changes in our management.

                                       51
<PAGE>
    Washington law also imposes restrictions on certain transactions between a
corporation and certain significant shareholders. Chapter 23B.19.040 of the
Washington Business Corporation Act prohibits a "target corporation," with
certain exceptions, from engaging in certain significant business transactions
with an "acquiring person," which is defined as a person or group of persons
that beneficially owns 10% or more of the voting securities of the target
corporation, for a period of five years after the acquisition, unless the
transaction or acquisition of shares is approved by a majority of the members of
the target corporation's board of directors prior to the time of acquisition.
Such prohibited transactions include, among other things:

    - a merger or consolidation with, disposition of assets to, or issuance or
      redemption of stock to or from, the acquiring person;

    - termination of 5% or more of the employees of the target corporation as a
      result of the acquiring person's acquisition of 10% or more of the shares;
      or

    - allowing the acquiring person to receive any disproportionate benefits as
      a shareholder.

    After the five-year period, a "significant business transaction" may occur,
as long as it complies with certain "fair price" provisions of the statute. A
corporation may not "opt out" of this statute. This provision may have the
effect of delaying, deferring or preventing a change in control.

TRANSFER AGENT

    The transfer agent and registrar for our common stock is American Stock
Transfer & Trust Company.

                                       52
<PAGE>
                        SHARES ELIGIBLE FOR FUTURE SALE

    Upon completion of this offering, we will have outstanding 18,626,667 shares
of common stock, assuming no exercise of options or warrants after August 31,
1999. Of these shares, 5,450,000 shares will be freely tradable without
restriction or further registration under the Securities Act; provided, however,
that if shares are owned by "affiliates," as that term is defined in Rule 144
under the Securities Act, their sales of shares would be subject to certain
limitations and restrictions that are described below.

    The remaining 13,176,667 shares of common stock, held by existing
shareholders as of August 31, 1999 were issued and sold by us in reliance on
exemptions from the registration requirements of the Securities Act. All of
these shares are subject to lock-up agreements described below. Upon expiration
of the lock-up agreements on December 2, 1999, substantially all of these shares
will become eligible for sale, subject in most cases to the limitations of Rules
144 and 701. In addition, holders of stock options and warrants could exercise
their options and warrants and sell the shares issued upon exercise as described
below.

    As of August 31, 1999, there were a total of 2,212,500 shares of common
stock that could be issued upon exercise of outstanding warrants. All of these
shares are subject to lock-up agreements. As of August 31, 1999, there were a
total of 2,440,405 shares of common stock subject to outstanding options under
our stock plans, of which 1,260,049 were vested. However, all of these shares
are subject to lock-up agreements. Shares purchased upon exercise of options
granted pursuant to our Amended and Restated 1996 Stock Option Plan, Amended and
Restated Directors' Nonqualified Stock Option Plan, 1998 Equity Incentive Plan,
1999 Non-Employees Directors' Plan and 1999 Employee Stock Purchase Plan
generally are available for resale in the public market after expiration of the
lock-up period.

    In connection with our initial public offering, the officers, directors and
then existing shareholders of F5 agreed not to sell or otherwise dispose of any
of their shares for a period ending December 2, 1999. Hambrecht & Quist,
however, may in its sole discretion, at any time and in most cases without
notice, release all or any portion of the shares subject to lock-up agreements.

RULE 144

    In general, under Rule 144 as currently in effect, a person who has
beneficially owned shares of F5's common stock for at least one year would be
entitled to sell, within any three-month period, a number of shares that does
not exceed the greater of:

    - 1% of the number of shares of common stock then outstanding, which will
      equal approximately 186,000 shares immediately after the effective date of
      this offering; or

    - the average weekly trading volume of the common stock on the Nasdaq
      National Market during the four calendar weeks preceding the filing of a
      notice on Form 144 with respect to this sale.

    Sales under Rule 144 are also subject to other requirements regarding the
manner of sale, notice filing and the availability of current public information
about F5.

RULE 701

    In general, under Rule 701, any F5 employee, director, officer, consultant
or advisor who purchases shares from F5 in connection with a compensatory stock
or option plan or other written agreement before the effective date of the
offering is entitled to resell these shares 90 days after the effective date of
this offering in reliance on Rule 144, without having to comply with certain
restrictions, including the holding period, contained in Rule 144.

    The SEC has indicated that Rule 701 will apply to typical stock options
granted by an issuer before it becomes subject to the reporting requirements of
the Securities Exchange Act of 1934, along with the

                                       53
<PAGE>
shares acquired upon exercise of these options (including exercises after the
date of this prospectus). Securities issued in reliance on Rule 701 are
restricted securities and, subject to the contractual restrictions described
above, beginning 90 days after the date of this prospectus, may be sold by
persons other than affiliates subject only to the manner of sale provisions of
Rule 144 and by affiliates under Rule 144 without compliance with its one year
minimum holding period requirement.

                                       54
<PAGE>
                                  UNDERWRITING

    Subject to the terms and conditions of the underwriting agreement, the
underwriters named below, through their representatives, Hambrecht & Quist LLC,
BancBoston Robertson Stephens Inc., Bear, Stearns & Co. Inc. and Dain Rauscher
Wessels, a division of Dain Rauscher Incorporated, have severally agreed to
purchase from F5 and the selling shareholders the following respective numbers
of shares of common stock.

<TABLE>
<CAPTION>
NAME                                                       NUMBER OF SHARES
- ---------------------------------------------------------  ----------------
<S>                                                        <C>
Hambrecht & Quist LLC....................................        968,000
BancBoston Robertson Stephens Inc........................        396,000
Bear, Stearns & Co. Inc..................................        396,000
Dain Rauscher Wessels, a division of Dain Rauscher
  Incorporated...........................................        440,000
                                                           ----------------
  Total..................................................      2,200,000
                                                           ----------------
                                                           ----------------
</TABLE>

    The underwriting agreement provides that the obligations of the underwriters
are subject to certain conditions precedent, including the absence of any
material adverse change in our business and the receipt of certain certificates,
opinions and letters from F5 and the selling shareholders, their counsel and the
independent auditors. The nature of the underwriters' obligation is such that
they have committed to purchase all shares of common stock offered hereby if any
of these shares are purchased.

    The underwriters are offering the shares of common stock directly to the
public at the public offering price set forth on the cover page of this
prospectus and to certain dealers at this price less a concession not in excess
of $2.00 per share. The underwriters may allow and these dealers may re-allow a
concession not in excess of $.10 per share to certain other dealers. After the
public offering of the shares, the underwriters may change the offering price
and other selling terms.

    Certain shareholders have granted to the underwriters an option, exercisable
no later than 30 days after the date of this prospectus, to purchase up to
330,000 additional shares of common stock at the public offering price, less the
underwriting discount set forth on the cover page of this prospectus. To the
extent that the underwriters exercise this option, each of the underwriters will
have a firm commitment to purchase approximately the same percentage thereof
which the number of shares of common stock to be purchased by it shown in the
above table bears to the total number of shares of common stock offered hereby.
F5 and such shareholders will be obligated, pursuant to the option, to sell
shares to the underwriters to the extent the option is exercised. The
underwriters may exercise this option only to cover over-allotments made in
connection with the sale of shares of common stock offered hereby. Kent L.
Johnson, a director of the Company, is the president of Alexander Hutton
Capital, L.L.C., which is a member of the NASD. Mr. Johnson is one of the
shareholders who has granted the underwriters an option to purchase additional
shares in connection with their exercise of the over-allotment option.

    The offering of the shares is made for delivery when, as and if accepted by
the underwriters and subject to prior sale and to withdrawal, cancellation or
modification of the offering without notice. The underwriters reserve the right
to reject an order for the purchase of shares in whole or in part.

    F5 and the selling shareholders have agreed to indemnify the underwriters
against certain liabilities, including liabilities under the Securities Act, and
to contribute to payments the underwriters may be required to make in respect
thereof.

    We have agreed that we will not, without the prior written consent of
Hambrecht & Quist LLC, offer, sell or otherwise dispose of any shares of common
stock, options or warrants to acquire shares of common stock or securities
exchangeable for or convertible into shares of common stock during the 90-day
period following the date of this prospectus, except that we may issue shares
upon the exercise of options granted prior to the date hereof, and may grant
additional options under our stock option plans.

                                       55
<PAGE>
    Certain persons participating in this offering may over-allot or effect
transactions that stabilize, maintain or otherwise affect the market price of
the common stock at levels above those that might otherwise prevail in the open
market, including by entering stabilizing bids, effecting syndicate covering
transactions or imposing penalty bids. A stabilizing bid means the placing of
any bid or effecting of any purchase, for the purpose of pegging, fixing or
maintaining the price of the common stock. A syndicate covering transaction
means the placing of any bid on behalf of the underwriting syndicate or the
effecting of any purchase to reduce a short position created in connection with
the offering. A penalty bid means an arrangement that permits the underwriters
to reclaim a selling concession from a syndicate member in connection with the
offering when shares of common stock sold by the syndicate member are purchased
in syndicate covering transactions. Such transactions may be effected on the
Nasdaq National Market, in the over-the-counter market, or otherwise. Such
stabilizing, if commenced may be discontinued at any time.

                                 LEGAL MATTERS

    The validity of the common stock offered hereby will be passed upon for F5
by Heller Ehrman White & McAuliffe, Seattle, Washington. Certain legal matters
will be passed upon for the underwriters by Gunderson Dettmer Stough Villeneuve
Franklin & Hachigian, LLP, Menlo Park, California.

                                    EXPERTS

    The financial statements as of September 30, 1997 and 1998 and June 30, 1999
and for the period from February 26, 1996, (inception), to September 30, 1996
and for each of the two years in the period ended September 30, 1998 and for the
nine months ended June 30, 1999 included in this prospectus have been so
included in reliance on the report of PricewaterhouseCoopers LLP, independent
accountants, given on the authority of said firm as experts in auditing and
accounting.

                           ADDITIONAL F5 INFORMATION

    We have filed with the SEC a registration statement on Form S-1 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 or the exhibits and schedules which are part of the
registration statement. For further information with respect to F5 and our
common stock, reference is made to the registration statement and the exhibits
and schedules thereto. You may read and copy any document we file at the SEC's
public reference rooms in Washington, D.C., New York, New York and Chicago,
Illinois. Please call the SEC at 1-800-SEC-0330 for further information about
the public reference rooms. Our SEC filings are also available to the public
from the SEC's Web site at
http://www.sec.gov. Information contained on F5's Web site does not constitute
part of this prospectus.

    We are subject to the information and periodic reporting requirements of the
Securities Exchange Act of 1934 and, in accordance therewith, file periodic
reports, proxy statements and other information with the SEC. Such periodic
reports, proxy statements and other information are available for inspection and
copying at the SEC's public reference rooms, our Web site and the Web site of
the SEC referred to above.

                                       56
<PAGE>
                               F5 NETWORKS, INC.
                         INDEX TO FINANCIAL STATEMENTS

<TABLE>
<CAPTION>
                                                                                                                PAGE
                                                                                                                -----
<S>                                                                                                          <C>
Report of Independent Accountants..........................................................................         F-2

Balance Sheets.............................................................................................         F-3

Statements of Operations...................................................................................         F-4

Statement of Shareholders' Equity (Deficit)................................................................         F-5

Statements of Cash Flows...................................................................................         F-6

Notes to Financial Statements..............................................................................         F-7
</TABLE>

                                      F-1
<PAGE>
                       REPORT OF INDEPENDENT ACCOUNTANTS

To the Board of Directors and Shareholders of
F5 Networks, Inc.

    In our opinion, the accompanying balance sheets and the related statements
of operations, of shareholders' equity (deficit) and of cash flows present
fairly, in all material respects, the financial position of F5 Networks, Inc. at
September 30, 1997 and 1998 and June 30, 1999, and the results of its operations
and its cash flows for the period from February 26, 1996 (inception) to
September 30, 1996 and for each of the years in the two year period ended
September 30, 1998 and for the nine months ended June 30, 1999, in conformity
with generally accepted accounting principles. 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. We conducted our
audits of these statements in accordance with generally accepted auditing
standards which 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, assessing the
accounting principles used and significant estimates made by management, and
evaluating the overall financial statement presentation. We believe that our
audits provide a reasonable basis for the opinion expressed above.

PricewaterhouseCoopers LLP

Seattle, Washington
September 2, 1999

                                      F-2
<PAGE>
                               F5 NETWORKS, INC.

                                 BALANCE SHEETS
                       (IN THOUSANDS, EXCEPT SHARE DATA)

<TABLE>
<CAPTION>
                                                                   SEPTEMBER 30,    SEPTEMBER 30,    JUNE 30,
                                                                       1997             1998           1999
                                                                  ---------------  ---------------  -----------
<S>                                                               <C>              <C>              <C>
                                                    ASSETS
Current assets:
  Cash and cash equivalents.....................................     $     143        $   6,206      $  26,948
  Accounts receivable, net of allowances of $0, $382 and $826...           329            2,032          5,858
  Inventories...................................................            77               99            710
  Other current assets..........................................            68              250            839
                                                                        ------           ------     -----------
        Total current assets....................................           617            8,587         34,355
Property and equipment, net.....................................           196              682          1,925
Software development costs, net of accumulated amortization of
  $4, $83 and $158..............................................            52              118             43
Other assets....................................................            54               45            163
                                                                        ------           ------     -----------
        Total assets............................................     $     919        $   9,432      $  36,486
                                                                        ------           ------     -----------
                                                                        ------           ------     -----------

                                LIABILITIES AND SHAREHOLDERS' EQUITY (DEFICIT)

Current liabilities:
  Accounts payable..............................................     $     117        $     559      $   3,540
  Accrued liabilities...........................................           114              458          1,579
  Deferred revenue..............................................           184              788          2,462
  Current portion of long-term debt.............................           500
  Capital lease obligations, current portion....................            19               19
                                                                        ------           ------     -----------
        Total current liabilities...............................           934            1,824          7,581
Capital lease obligations, net of current portion...............            19
Long-term debt, net of current portion..........................           197
                                                                        ------           ------     -----------
        Total liabilities.......................................         1,150            1,824          7,581
                                                                        ------           ------     -----------
Commitments (Note 9)
Redeemable convertible preferred stock, no par value:
  Series D Convertible, no, 1,138,438 and no shares issued and
    outstanding.................................................                          7,688
                                                                        ------           ------     -----------
Shareholders' equity (deficit):
  Preferred stock, no par value; 10,000,000 shares authorized
    Series A Convertible, 400,000, 400,000 and no shares issued
      and outstanding...........................................         1,123            1,123
    Series B Convertible, 156,250, 1,250,000 and no shares
      issued and outstanding....................................           208            1,656
    Series C Convertible, no, 156,250 and no shares issued and
      outstanding...............................................                          1,418
  Common stock, no par value; 100,000,000 shares authorized,
    6,000,000, 6,021,500 and 18,108,185 shares issued and
    outstanding.................................................           393            2,875         45,751
  Note receivable from shareholder..............................                                          (750)
  Unearned compensation.........................................          (169)          (1,694)        (3,960)
  Accumulated deficit...........................................        (1,786)          (5,458)       (12,136)
                                                                        ------           ------     -----------
      Total shareholders' equity (deficit)......................          (231)             (80)        28,905
                                                                        ------           ------     -----------
        Total liabilities and shareholders' equity..............     $     919        $   9,432      $  36,486
                                                                        ------           ------     -----------
                                                                        ------           ------     -----------
</TABLE>

   The accompanying notes are an integral part of these financial statements.

                                      F-3
<PAGE>
                               F5 NETWORKS, INC.

                            STATEMENTS OF OPERATIONS
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)

<TABLE>
<CAPTION>
                                            PERIOD FROM
                                           FEBRUARY 26,
                                               1996        YEAR ENDED SEPTEMBER  NINE MONTHS ENDED JUNE
                                          (INCEPTION) TO           30,                    30,
                                           SEPTEMBER 30,   --------------------  ----------------------
                                               1996          1997       1998        1998        1999
                                          ---------------  ---------  ---------  -----------  ---------
                                                                                 (UNAUDITED)
<S>                                       <C>              <C>        <C>        <C>          <C>
Net revenues:
  Products..............................     $       2     $     229  $   4,119   $   2,537   $  11,872
  Services..............................            --            --        770         444       2,190
                                                ------     ---------  ---------  -----------  ---------
    Total net revenues..................             2           229      4,889       2,981      14,062
                                                ------     ---------  ---------  -----------  ---------

Cost of net revenues:
  Products..............................             1            71      1,091         694       3,085
  Services..............................            --            --        314         171         976
                                                ------     ---------  ---------  -----------  ---------
    Total cost of net revenues..........             1            71      1,405         865       4,061
                                                ------     ---------  ---------  -----------  ---------

  Gross profit..........................             1           158      3,484       2,116      10,001
                                                ------     ---------  ---------  -----------  ---------

Operating expenses:
  Sales and marketing...................            62           565      3,881       2,439       9,113
  Research and development..............           103           569      1,810       1,059       3,810
  General and administrative............           180           383      1,041         690       2,145
  Amortization of unearned
    compensation........................             4            69        420         205       1,797
                                                ------     ---------  ---------  -----------  ---------
    Total operating expenses............           349         1,586      7,152       4,393      16,865
                                                ------     ---------  ---------  -----------  ---------
Loss from operations....................          (348)       (1,428)    (3,668)     (2,277)     (6,864)
Other income (expense):
  Interest expense......................            --           (46)       (42)        (36)         (2)
  Interest income.......................            18            18         38          15         188
                                                ------     ---------  ---------  -----------  ---------
    Net loss............................     $    (330)    $  (1,456) $  (3,672)  $  (2,298)  $  (6,678)
                                                ------     ---------  ---------  -----------  ---------
                                                ------     ---------  ---------  -----------  ---------
Net loss per share--basic and diluted...     $   (0.06)    $   (0.24) $   (0.60)  $   (0.37)  $   (0.88)
                                                ------     ---------  ---------  -----------  ---------
                                                ------     ---------  ---------  -----------  ---------
Weighted average shares--basic and
  diluted...............................         5,932         6,000      6,086       6,135       7,582
                                                ------     ---------  ---------  -----------  ---------
                                                ------     ---------  ---------  -----------  ---------
Pro forma net loss per share
  (unaudited):
  Net loss per share--basic and
    diluted.............................                              $   (0.26)              $   (0.45)
                                                                      ---------               ---------
                                                                      ---------               ---------
  Weighted average shares--basic and
    diluted.............................                                 14,201                  14,923
                                                                      ---------               ---------
                                                                      ---------               ---------
</TABLE>

   The accompanying notes are an integral part of these financial statements.

                                      F-4
<PAGE>
                               F5 NETWORKS, INC.
                  STATEMENT OF SHAREHOLDERS' EQUITY (DEFICIT)
       FOR THE PERIOD FROM FEBRUARY 26, 1996 (INCEPTION) TO JUNE 30, 1999
                       (IN THOUSANDS, EXCEPT SHARE DATA)
<TABLE>
<CAPTION>
                                   CONVERTIBLE PREFERRED STOCK AMOUNT
                                -----------------------------------------
                                 SHARES    SERIES A   SERIES B   SERIES C
                                ---------  --------   --------   --------
<S>                             <C>        <C>        <C>        <C>
Common stock issued to
  founding shareholders.......
Common stock issued for
  merger......................
Sales of Series A Convertible
  Preferred Stock,
  (net of issuance costs of
    $77)......................    370,000   $ 1,123
Issuance of Series A
  Convertible Preferred Stock
  upon payment of subscription
  receivable from
  shareholder.................     10,000
Unearned compensation.........
Amortization of unearned
  compensation................
Net loss......................
                                ---------  --------   --------   --------
Balance, September 30, 1996...    380,000     1,123
Issuance of Series A
  Convertible Preferred Stock
  upon payment of subscription
  receivable from
  shareholders................     20,000
Sales of Series B Convertible
  Preferred Stock.............    156,250              $   250
Value ascribed to warrants
  issued in conjunction with
  sale of Convertible
  Preferred Stock.............                             (42)
Value ascribed to warrants
  issued with note payable....
Unearned compensation.........
Amortization of unearned
  compensation................
Net loss......................
                                ---------  --------   --------   --------
Balance, September 30, 1997...    556,250     1,123        208
Sales of Series B Convertible
  Preferred Stock, (net of
  issuance costs of $30)......  1,093,750                1,740
Sales of Series C Convertible
  Preferred Stock, (net of
  issuance costs of $7).......    156,250                         $ 1,493
Value ascribed to warrants
  issued in conjunction with
  sales of Convertible
  Preferred Stock.............                            (292)       (75)
Exercise of stock options by
  employees...................
Exercise of stock warrants....
Repurchase of common stock
  under shareholder
  agreement...................
Issuance of common stock under
  shareholder agreement.......
Conversion of note payable to
  common stock................
Unearned compensation.........
Amortization of unearned
  compensation................
Net loss......................
                                ---------  --------   --------   --------
Balance, September 30, 1998...  1,806,250     1,123      1,656      1,418
Exercise of stock options by
  employees...................
Exercise of stock warrants....
Note receivable from
  shareholder for exercise of
  stock options ..............
Unearned compensation.........
Amortization of unearned
  compensation................
Conversion of convertible
  preferred stock to common
  stock in connection with the
  initial public offering.....  (1,806,250)   (1,123)   (1,656)    (1,418)
Issuance of common stock in an
  initial public offering (net
  of issuance costs of
  $3,051).....................
Net loss......................
                                ---------  --------   --------   --------
Balance, June 30, 1999........              $          $          $
                                ---------  --------   --------   --------
                                ---------  --------   --------   --------

<CAPTION>
                                                    SUBSCRIPTIONS
                                                       /NOTES
                                   COMMON STOCK      RECEIVABLE      UNEARNED
                                ------------------      FROM         COMPEN-     ACCUMULATED
                                  SHARES    AMOUNT  SHAREHOLDERS      SATION       DEFICIT      TOTAL
                                ----------  ------  -------------   ----------   -----------   -------
<S>                             <C>         <C>     <C>             <C>          <C>           <C>
Common stock issued to
  founding shareholders.......   5,388,000
Common stock issued for
  merger......................     612,000
Sales of Series A Convertible
  Preferred Stock,
  (net of issuance costs of
    $77)......................                          $(90)                                  $ 1,033
Issuance of Series A
  Convertible Preferred Stock
  upon payment of subscription
  receivable from
  shareholder.................                            30                                        30
Unearned compensation.........              $    4                   $    (4)
Amortization of unearned
  compensation................                                             4                         4
Net loss......................                                                     $  (330)       (330)
                                ----------  ------  -------------   ----------   -----------   -------
Balance, September 30, 1996...   6,000,000       4       (60)                         (330)        737
Issuance of Series A
  Convertible Preferred Stock
  upon payment of subscription
  receivable from
  shareholders................                            60                                        60
Sales of Series B Convertible
  Preferred Stock.............                                                                     250
Value ascribed to warrants
  issued in conjunction with
  sale of Convertible
  Preferred Stock.............                  42
Value ascribed to warrants
  issued with note payable....                 109                                                 109
Unearned compensation.........                 238                      (238)
Amortization of unearned
  compensation................                                            69                        69
Net loss......................                                                      (1,456)     (1,456)
                                ----------  ------  -------------   ----------   -----------   -------
Balance, September 30, 1997...   6,000,000     393                      (169)       (1,786)       (231)
Sales of Series B Convertible
  Preferred Stock, (net of
  issuance costs of $30)......                                                                   1,740
Sales of Series C Convertible
  Preferred Stock, (net of
  issuance costs of $7).......                                                                   1,493
Value ascribed to warrants
  issued in conjunction with
  sales of Convertible
  Preferred Stock.............                 367
Exercise of stock options by
  employees...................     215,750      29                                                  29
Exercise of stock warrants....       5,750       5                                                   5
Repurchase of common stock
  under shareholder
  agreement...................  (2,600,000)   (245)                                               (245)
Issuance of common stock under
  shareholder agreement.......   1,800,000     172                                                 172
Conversion of note payable to
  common stock................     600,000     209                                                 209
Unearned compensation.........               1,945                    (1,945)
Amortization of unearned
  compensation................                                           420                       420
Net loss......................                                                      (3,672)     (3,672)
                                ----------  ------  -------------   ----------   -----------   -------
Balance, September 30, 1998...   6,021,500   2,875                    (1,694)       (5,458)        (80)
Exercise of stock options by
  employees...................     534,809     209                                                 209
Exercise of stock warrants....     427,500     420                                                 420
Note receivable from
  shareholder for exercise of
  stock options ..............     150,000     750      (750)
Unearned compensation.........               4,063                    (4,063)
Amortization of unearned
  compensation................                                         1,797                     1,797
Conversion of convertible
  preferred stock to common
  stock in connection with the
  initial public offering.....   8,114,376  11,885                                               7,688
Issuance of common stock in an
  initial public offering (net
  of issuance costs of
  $3,051).....................   2,860,000  25,549                                              25,549
Net loss......................                                                      (6,678)     (6,678)
                                ----------  ------  -------------   ----------   -----------   -------
Balance, June 30, 1999........  18,108,185  $45,751     $(750)       $(3,960)      $(12,136)   $28,905
                                ----------  ------  -------------   ----------   -----------   -------
                                ----------  ------  -------------   ----------   -----------   -------
</TABLE>

   The accompanying notes are an integral part of these financial statements.

                                      F-5
<PAGE>
                               F5 NETWORKS, INC.

                            STATEMENTS OF CASH FLOWS
                                 (IN THOUSANDS)

<TABLE>
<CAPTION>
                                                          PERIOD FROM      YEAR ENDED SEPTEMBER  NINE MONTHS ENDED JUNE
                                                       FEBRUARY 26, 1996           30,                    30,
                                                        (INCEPTION) TO     --------------------  ----------------------
                                                      SEPTEMBER 30, 1996     1997       1998        1998        1999
                                                      -------------------  ---------  ---------  -----------  ---------
                                                                                                 (UNAUDITED)
<S>                                                   <C>                  <C>        <C>        <C>          <C>
Cash flows from operating activities:
  Net loss..........................................       $    (330)      $  (1,456) $  (3,672)  $  (2,298)  $  (6,678)
  Adjustments to reconcile net loss to net cash used
    in operating activities:
    Amortization of unearned compensation...........               4              69        420         205       1,797
    Provision for doubtful accounts and sales
      returns.......................................                                        605         399       1,078
    Depreciation and amortization...................              14              59        323         213         364
    Non cash interest expense.......................                               6         12          12
    Changes in operating assets and liabilities:
      Accounts receivable...........................              (1)           (328)    (2,308)     (1,108)     (4,904)
      Inventories...................................             (29)            (48)       (22)        (48)       (611)
      Other current assets..........................              (7)            (55)      (186)        (62)       (589)
      Other assets..................................              (6)            (48)         9          13        (119)
      Accounts payable and accrued liabilities......              37             194        806         762       4,100
      Deferred revenue..............................                             184        604         181       1,674
                                                              ------       ---------  ---------  -----------  ---------
        Net cash used in operating activities.......            (318)         (1,423)    (3,409)     (1,731)     (3,888)
                                                              ------       ---------  ---------  -----------  ---------
Cash flows from investing activities:
  Issuance of notes to officer......................                                        (10)        (10)
  Purchases of property and equipment...............            (150)            (98)      (731)       (425)     (1,531)
  Additions to software development costs...........                             (56)      (145)       (145)
  Proceeds from sale leaseback......................              30
                                                              ------       ---------  ---------  -----------  ---------
        Net cash used in investing activities.......            (120)           (154)      (886)       (580)     (1,531)
                                                              ------       ---------  ---------  -----------  ---------
Cash flows from financing activities:
  Proceeds from issuance of common stock in an
    initial public offering.........................                                                             25,549
  Proceeds from issuance of Series A Convertible
    Preferred Stock.................................           1,063              60
  Proceeds from issuance of Series B Convertible
    Preferred Stock.................................                             250      1,235       1,235
  Proceeds from issuance of Series C Convertible
    Preferred Stock.................................                                      1,493       1,493
  Proceeds from issuance of Series D Redeemable
    Convertible Preferred Stock.....................                                      7,688
  Proceeds from the exercise of stock options and
    warrants........................................                                         34          28         629
  Repurchase of common stock under shareholder
    agreement.......................................                                       (245)       (245)
  Proceeds from issuance of common stock under
    shareholder agreement...........................                                        172         172
  Proceeds from line of credit......................                                        825       1,075
  Repayments of line of credit......................                                       (825)       (825)
  Proceeds from issuance of long-term debt..........                             800
  Principal payments on capital lease obligations...              (1)            (14)       (19)        (16)        (17)
                                                              ------       ---------  ---------  -----------  ---------
        Net cash provided by financing activities...           1,062           1,096     10,358       2,917      26,161
                                                              ------       ---------  ---------  -----------  ---------
        Net increase (decrease) in cash and cash
          equivalents...............................             624            (481)     6,063         606      20,742
Cash and cash equivalents, at beginning of year.....              --             624        143         143       6,206
                                                              ------       ---------  ---------  -----------  ---------
Cash and cash equivalents, at end of year...........       $     624       $     143  $   6,206   $     749   $  26,948
                                                              ------       ---------  ---------  -----------  ---------
                                                              ------       ---------  ---------  -----------  ---------
</TABLE>

   The accompanying notes are an integral part of these financial statements.

                                      F-6
<PAGE>
                               F5 NETWORKS, INC.

                         NOTES TO FINANCIAL STATEMENTS

1.  THE COMPANY AND BASIS OF PRESENTATION:

    F5 Networks, Inc. (formerly F5 Labs, Inc.) (the "Company") was incorporated
    on February 26, 1996 in the State of Washington.

    F5 is a leading provider of integrated Internet traffic management solutions
    designed to improve the availability and performance of mission-critical
    Internet-based servers and applications. The Company's proprietary
    software-based solutions monitor and manage local and geographically
    dispersed servers and intelligently direct traffic to the server best able
    to handle a user's request.

    The Company purchases material component parts and certain licensed software
    from suppliers and generally contracts with third parties for the assembly
    of products.

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:

    USE OF ESTIMATES

    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 assets and liabilities and
    disclosures of contingent assets and liabilities as of the date of the
    financial statements and the reported amounts of expenses during the
    reporting period. Actual results could differ from those estimates.

    UNAUDITED INTERIM FINANCIAL STATEMENTS

    In the opinion of the Company's management, the June 30, 1998 unaudited
    interim financial statements include all adjustments, consisting of normal
    recurring adjustments, necessary for a fair presentation of the financial
    statements. All references hereinafter to June 30, 1998 amounts are based on
    unaudited information.

    CASH EQUIVALENTS AND SHORT-TERM INVESTMENTS

    The Company considers all highly liquid investment securities with a
    maturity from the date of purchase of three months or less to be cash
    equivalents and investment securities with a weighted average maturity from
    the date of purchase of more than three months but less than one year to be
    short-term investments. As of June 30, 1999, the Company did not hold any
    short-term investments within its investment portfolio.

    CONCENTRATION OF CREDIT RISK

    The Company places its temporary cash investments with major financial
    institutions. As of June 30, 1999, all of the Company's temporary cash
    investments were placed with four institutions.

    The Company's customers are from diverse industries and geographic
    locations. Net revenues from international customers are denominated in U.S.
    Dollars and were approximately $0, $15,000 and $172,000 in the period from
    February 26, 1996 (inception) to September 30, 1996, and the years ended
    September 30, 1997 and 1998, respectively and $122,000 and $1.0 million for
    the nine months ended June 30, 1998 and 1999. For the nine months ended June
    30, 1999, one customer accounted for 21.7% of net revenues. During the
    period from February 26, 1996 (inception) to September 30, 1996, the years
    ended September 30, 1997 and 1998, and the nine months ended June 30, 1998,
    no single customer accounted for more than 10% of the Company's net
    revenues. At June 30, 1999, one

                                      F-7
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: (CONTINUED)
    customer represented 29.4% of accounts receivable. At September 30, 1997 and
    1998, there were no significant accounts receivable from a single customer.
    The Company does not require collateral to support credit sales. Allowances
    are maintained for potential credit losses and sales returns.

    INVENTORIES

    Inventories consist of hardware, software and related component parts and
    are recorded at the lower of cost or market (as determined by the first-in,
    first-out method).

    PROPERTY AND EQUIPMENT

    Property and equipment is stated at cost. Equipment under capital leases is
    stated at the lower of the present value of the minimum lease payments
    discounted at the Company's incremental borrowing rate at the beginning of
    the lease term or fair value at the inception of the lease. Depreciation of
    property and equipment and amortization of capital leases are provided on
    the straight-line method over the estimated useful lives of the assets of 2
    to 5 years. Leasehold improvements are amortized over the lesser of the term
    of the lease or the estimated useful life of the improvements.

    The cost of normal maintenance and repairs is charged to expense as incurred
    and expenditures for major improvements are capitalized at cost. Gains or
    losses on the disposition of assets in the normal course of business are
    reflected in the results of operations at the time of disposal.

    SOFTWARE DEVELOPMENT COSTS

    Software development costs incurred in conjunction with product development
    are charged to research and development expense until technological
    feasibility is established. Thereafter, until the product is released for
    sale, software development costs are capitalized and reported at the lower
    of unamortized cost or net realizable value of each product. The
    establishment of technological feasibility and the on-going assessment of
    recoverability of costs require considerable judgment by the Company with
    respect to certain internal and external factors, including, but not limited
    to, anticipated future gross product revenues, estimated economic life and
    changes in hardware and software technology. The Company amortizes
    capitalized software costs using the straight-line method over the estimated
    economic life of the product, generally two years.

    VALUATION OF LONG-LIVED ASSETS

    The Company periodically evaluates the carrying value of long-lived assets
    to be held and used, including, but not limited to, property and equipment
    and other assets, when events and circumstances warrant such a review. The
    carrying value of a long-lived asset is considered impaired when the
    anticipated undiscounted cash flow from the asset is separately identifiable
    and is less than its carrying value. In that event, a loss is recognized
    based on the amount by which the carrying value exceeds the fair value of
    the long-lived asset. Fair value is determined primarily using the
    anticipated cash flows discounted at a rate commensurate with the risk
    involved. Losses on long-lived assets to be disposed of are determined in a
    similar manner, except that fair values are reduced for the cost to dispose.

                                      F-8
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: (CONTINUED)
    REVENUE RECOGNITION

    The Company recognizes software revenue under Statement of Position 97-2,
    "Software Revenue Recognition," and SOP 98-9 "Modification of SOP 97-2,
    Software Revenue Recognition, with Respect to Certain Transactions."

    The Company sells products through resellers, original equipment
    manufacturers and other channel partners, as well as to end users, under
    similar terms. The Company generally combines software license, installation
    and customer support elements into a package with a single "bundled" price.
    The Company allocates a portion of the sales price to each element of the
    bundled package based on their respective fair values when the individual
    elements are sold separately. Revenues from the license of software, net of
    an allowance for estimated returns, are recognized when the product has been
    shipped and the customer is obligated to pay for the product. Installation
    revenue is recognized when the product has been installed at the customer's
    site. Revenues for customer support are recognized on a straight-line basis
    over the service contract terms. Estimated sales returns are based on
    historical experience by product and are recorded at the time revenues are
    recognized.

    ADVERTISING

    Advertising costs are expensed as incurred. Advertising expense was $0, $0
    and $256,000 for the period from February 26, 1996 (inception) to September
    30, 1996 and the years ended September 30, 1997 and 1998, respectively, and
    $142,000 and $794,000, for the nine months ended June 30, 1998 and 1999,
    respectively.

    INCOME TAXES

    The Company accounts for income taxes under the liability method of
    accounting. Under the liability method, deferred taxes are determined based
    on the differences between the financial statement and tax bases of assets
    and liabilities at enacted tax rates in effect in the year in which the
    differences are expected to reverse. Valuation allowances are established,
    when necessary, to reduce deferred tax assets to amounts expected to be
    realized.

    STOCK-BASED COMPENSATION

    The Company accounts for stock-based employee compensation arrangements in
    accordance with the provisions of Accounting Principles Board Opinion No. 25
    ("APB No. 25"), "Accounting for Stock Issued to Employees" and complies with
    the disclosure provisions of Statement of Financial Accounting Standards No.
    123 ("SFAS No. 123"), "Accounting for Stock-Based Compensation." Under APB
    No. 25, compensation expense is based on the difference, if any, on the date
    of the grant, between the deemed fair value of the Company's stock and the
    exercise price of the option. The unearned compensation is being amortized
    in accordance with Financial Accounting Standards Board Interpretation No.
    28 on an accelerated basis over the vesting period of the individual
    options. The Company accounts for equity instruments issued to nonemployees
    in accordance with the provisions of SFAS No. 123.

                                      F-9
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: (CONTINUED)
    FAIR VALUE OF FINANCIAL INSTRUMENTS

    For certain financial instruments, including cash and cash equivalents,
    accounts receivable, accounts payable and accrued liabilities, recorded
    amounts approximate market value.

    NET LOSS PER SHARE

    Effective October 1, 1997, the Company adopted Statement of Financial
    Accounting Standards No. 128 ("SFAS No. 128"), "Earnings per Share." SFAS
    No. 128 requires the presentation of basic and diluted earnings (loss) per
    share for all periods presented.

    In accordance with SFAS No. 128, basic net loss per share has been computed
    using the weighted-average number of shares of common stock outstanding
    during the period, except that pursuant to Securities and Exchange
    Commission Staff Accounting Bulletin No. 98, if applicable, common shares
    issued in each of the periods presented for nominal consideration have been
    included in the calculation as if they were outstanding for all periods
    presented. Pro forma basic and diluted net loss per share have been computed
    as described above and also include the weighted average convertible
    preferred stock outstanding as if those shares were converted to common
    stock at the time of issuance.

    Dilutive securities include options, warrants and preferred stock on an as
    if converted basis. Potentially dilutive securities totaling 3,636,000 for
    the period from February 26, 1996 (inception) to September 30, 1996 and
    5,066,000 and 12,819,126 for the years ended September 30, 1997 and 1998,
    respectively, and 10,582,126 and 4,581,762 for the nine months ended June
    30, 1998 (unaudited) and 1999, respectively, were excluded from historical
    basic and diluted loss per share because of their anti-dilutive effect.

    NEW ACCOUNTING PRONOUNCEMENTS

    In June 1997, the Financial Accounting Standards Board (the "FASB") issued
    Statement of Financial Accounting Standards No. 130, "Reporting
    Comprehensive Income." This statement requires that changes in comprehensive
    income be shown in a financial statement that is displayed with the same
    prominence as other financial statements. The statement is effective for
    fiscal years beginning after December 15, 1997. Reclassification for earlier
    periods is required for comparative purposes. The Company does not have any
    material items of comprehensive income, other than net loss, and
    accordingly, the statement does not have any material impact on reported
    financial position or results of operations.

    In June 1997, the FASB issued Statement of Financial Accounting Standards
    No. 131, "Disclosures About Segments of an Enterprise and Related
    Information." This statement supersedes Statement of Financial Accounting
    Standards No. 14, "Financial Reporting for Segments of a Business
    Enterprise." This statement includes requirements to report selected segment
    information quarterly and entity-wide disclosures about products and
    services, major customers, and geographic areas in which the entity holds
    significant assets and reports significant revenues. The statement is
    effective for fiscal year 1999. The Company operates in one segment
    providing integrated Internet traffic management solutions.

    In June 1998, the FASB issued Statement of Financial Accounting Standards
    No. 133, "Accounting for Derivative Instruments and Hedging Activities."
    This statement requires that all derivative

                                      F-10
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: (CONTINUED)
    instruments be recorded on the balance sheet at their fair value. Changes in
    the fair value of derivatives are recorded each period in current earnings
    or other comprehensive income, depending on whether a derivative is
    designated as part of a hedge transaction and, if it is, the type of hedge
    transaction. In July 1999, the FASB issued SFAS No. 137, "Accounting for
    Derivative Instruments and Hedging Activities--Deferral of the Effective
    Date of FASB Statement No. 133." SFAS No. 137 deferred the effective date of
    SFAS No. 133 until fiscal years beginning after June 15, 2000. The Company
    does not use derivative instruments, therefore the adoption of this
    statement will not have any effect on the Company's results of operations or
    its financial position.

    In March 1998, the American Institute of Certified Public Accountants issued
    Statement of Position 98-1, "Accounting for the Costs of Computer Software
    Developed or Obtained for Internal Use," which establishes guidelines for
    the accounting for the costs of all computer software developed or obtained
    for internal use. This statement is effective for fiscal years beginning
    after December 15, 1998. The Company does not expect the statement to have a
    material impact on its financial statements.

3.  PROPERTY AND EQUIPMENT:

    At September 30, 1997 and 1998 and June 30, 1999, property and equipment
    consist of the following:

<TABLE>
<CAPTION>
                                                                             SEPTEMBER 30,
                                                                          --------------------   JUNE 30,
                                                                            1997       1998        1999
                                                                             ---     ---------  -----------
                                                                                   (IN THOUSANDS)
<S>                                                                       <C>        <C>        <C>
Computer equipment......................................................  $     161  $     529   $   1,128
Equipment under capital leases..........................................         54         54          54
Office furniture and equipment..........................................         17        293         574
Leasehold improvements..................................................         29        116         330
Work in process.........................................................                               437
                                                                                ---  ---------  -----------
                                                                                261        992       2,523
Accumulated amortization for equipment under
  capital leases........................................................        (15)       (33)        (46)
Accumulated depreciation................................................        (50)      (277)       (552)
                                                                                ---  ---------  -----------
                                                                          $     196  $     682   $   1,925
                                                                                ---  ---------  -----------
                                                                                ---  ---------  -----------
</TABLE>

    Depreciation expense was approximately $14,000 for the period from February
    26, 1996 (inception) to September 30, 1996 and $55,000 and $244,000 for the
    years ended September 30, 1997 and 1998, respectively. Depreciation expense
    was approximately $161,000 and $289,000 for the nine months ended June 30,
    1998 (unaudited) and 1999, respectively.

                                      F-11
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

4.  ACCRUED LIABILITIES:

    At September 30, 1997 and 1998 and June 30, 1999, accrued liabilities
    consist of the following:

<TABLE>
<CAPTION>
                                                                               SEPTEMBER 30,
                                                                            --------------------   JUNE 30,
                                                                              1997       1998        1999
                                                                               ---        ---     -----------
                                                                                     (IN THOUSANDS)
<S>                                                                         <C>        <C>        <C>
Accrued payroll and benefits..............................................  $      37  $     237   $     871
Accrued sales and use taxes...............................................         17        141         287
Other.....................................................................         60         80         421
                                                                                  ---        ---  -----------
                                                                            $     114  $     458   $   1,579
                                                                                  ---        ---  -----------
                                                                                  ---        ---  -----------
</TABLE>

5.  INCOME TAXES:

    The provisions for federal income tax differs from the amount computed by
    applying the statutory federal income tax rate for the following reasons:

<TABLE>
<CAPTION>
                                                               SEPTEMBER 30,
                                                           ----------------------    JUNE 30,
                                                              1997        1998         1999
                                                           ----------  ----------  ------------
<S>                                                        <C>         <C>         <C>
Federal income tax benefit at statutory rate.............        (34)%       (34)%        (34)%
Non-deductible stock compensation........................          1%          3%           7%
Other....................................................                      1            1
                                                                 ---         ---          ---
Change in valuation allowance............................         33%         30%          26%
                                                                 ---         ---          ---
                                                                 ---         ---          ---
</TABLE>

    Deferred tax assets and liabilities at September 30, 1997 and 1998 and June
    30, 1999 consist of the following:

<TABLE>
<CAPTION>
                                                             SEPTEMBER 30,
                                                          --------------------   JUNE 30,
                                                            1997       1998        1999
                                                          ---------  ---------  -----------
<S>                                                       <C>        <C>        <C>
Deferred tax assets:
  Net operating loss carryforwards......................  $     583  $   1,573   $   3,000
  Allowance for doubtful accounts.......................                    80         281
  Accrued compensation and benefits.....................          8         61         116
  Depreciation..........................................                     9          19
                                                          ---------  ---------  -----------
    Total deferred tax assets...........................        591      1,723       3,416
                                                          ---------  ---------  -----------
Deferred tax liabilities:
  Depreciation..........................................         (7)
  Amortization..........................................        (14)       (53)        (13)
                                                          ---------  ---------  -----------
    Total deferred tax liabilities......................        (21)       (53)        (13)
                                                          ---------  ---------  -----------
                                                                570      1,670       3,403
Valuation allowance.....................................       (570)    (1,670)     (3,403)
                                                          ---------  ---------  -----------
                                                          $       0  $       0   $       0
                                                          ---------  ---------  -----------
                                                          ---------  ---------  -----------
</TABLE>

                                      F-12
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

5.  INCOME TAXES: (CONTINUED)
    Differences between the tax bases of assets and liabilities and their
    financial statement amounts are reflected as deferred income taxes based on
    enacted tax rates. The net deferred tax assets have been reduced by a full
    valuation allowance at September 30, 1997 and 1998 and June 30, 1999 based
    on management's determination that the recognition criteria for realization
    have not been met.

    As of June 30, 1999, the Company had net operating loss carryforwards of
    approximately $8.8 million, to offset future taxable income for Federal
    income tax purposes, which will expire between 2011 and 2019. Should certain
    changes in the Company's ownership occur, there could be a limitation on the
    utilization of its net operating losses.

6.  LINES OF CREDIT:

    In July 1998, the Company entered into a line of credit which allows the
    Company to borrow up to the lesser of $2.0 million or 75% of the Company's
    eligible accounts receivable. The terms of the agreement call for monthly
    interest payments, interest at the prime rate plus 0.5% and a due date of
    August 31, 1999. This line of credit was not renewed upon expiration. The
    line of credit contains certain covenants, including, but not limited to,
    meeting minimum financial ratios and earnings. No amount was outstanding
    under the line of credit at June 30, 1999.

7.  LONG-TERM DEBT:

    In March and August 1997, the Company entered into $500,000 and $300,000
    convertible note agreements with a preferred shareholder, respectively.
    These notes bore simple interest at 11% annually, matured 18 months from the
    date of the respective agreements and were collateralized by substantially
    all of the Company's assets. In October 1997, the Company settled the
    $500,000 note and related accrued interest by issuing to the preferred
    shareholder 312,500 shares of the Company's Series B Convertible Preferred
    Stock. In November 1997, the preferred shareholder converted the $300,000
    note and related accrued interest into 600,000 shares of the Company's
    common stock. In conjunction with these notes, the Company issued to the
    preferred shareholder warrants to purchase 100,000 and 600,000 shares of the
    Company's common stock at $0.64 and $0.50 per share, respectively. The
    aggregate value assigned to the warrants issued with these notes payable of
    $0 and $109,000, respectively, was reflected as both a debt discount and an
    increase to common stock. The debt discount was accounted for as a component
    of interest expense using a method which approximated the interest method.

8.  SHAREHOLDERS' EQUITY:

    A.  PREFERRED STOCK

    In connection with the Company's initial public offering (note 8c), all
    outstanding shares of the Company's Convertible Preferred Stock and
    Redeemable Convertible Preferred Stock were converted into an aggregate of
    8,114,376 shares of the Company's common stock.

    The Series A Convertible Preferred Stock is non-cumulative and convertible
    into six shares of common stock, subject to adjustment upon the occurrence
    of certain events provided for in the Company's restated articles of
    incorporation. The Series A Convertible Preferred Stock is mandatorily
    convertible into common stock upon completion of an initial public offering
    of the Company's common stock in which the price per share equals or exceeds
    $1.50 and gross proceeds equal or

                                      F-13
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

8.  SHAREHOLDERS' EQUITY: (CONTINUED)
    exceed $12.0 million, or when two-thirds of the shares of Series A
    Convertible Preferred Stock have been converted. The holders of the Series A
    Convertible Preferred Stock have certain voting rights and liquidation
    preferences equal to $3.00 per share.

    In May 1996, the Company issued 370,000 shares of Series A Convertible
    Preferred Stock for an aggregate purchase price of $1.1 million. In
    conjunction with the issuance of the Company's Series A shares to a certain
    investor, the Company issued warrants, to which no value was assigned, to
    purchase 240,000 shares of the Company's common stock at $0.50 per share. On
    December 30, 1998, these warrants were exercised.

    In addition, the Company entered into stock subscriptions for 30,000 shares
    of the Company's Series A Convertible Preferred Stock in exchange for notes
    receivable from certain investors for an aggregate of $90,000. These notes
    receivable bore interest at 9% per annum and had maturity periods ranging
    from 3 to 6 months from the date of the agreements. In August 1996, 10,000
    shares of the Company's Series A Convertible Preferred Stock were issued
    upon payment in full of $30,000 principal value and accrued interest of a
    subscription agreement. In fiscal year 1997, the Company issued the
    remaining 20,000 shares under subscription upon payment in full of the
    remaining principal amount and accrued interest.

    In September 1997, the Company issued 156,250 shares of Series B Convertible
    Preferred Stock for an aggregate purchase price of $250,000. In conjunction
    with this issuance, the Company issued warrants to purchase 187,500 shares
    of the Company's common stock at $0.80 per share. The Company has allocated
    approximately $42,000 of the purchase price as the value of these warrants.
    The Series B Convertible Preferred Stock is non-cumulative and convertible
    into two shares of the Company's common stock, subject to adjustment upon
    the occurrence of certain events provided for in the Company's amended and
    restated articles of incorporation. The Series B Convertible Preferred Stock
    is mandatorily convertible into common stock upon completion of an initial
    public offering of the Company's common stock in which the price per share
    equals or exceeds $3.20 and gross proceeds equal or exceed $8.0 million, or
    when two-thirds of the Series B shares have been converted. The holders of
    the Series B Convertible Preferred Stock have certain voting rights and
    liquidation preferences equal to $1.60 per share.

    In October and November 1997, the Company issued an additional 1,093,750
    shares of the Company's Series B Convertible Preferred Stock for an
    additional aggregate purchase price of $1.8 million, including conversion of
    the $500,000 note and accrued interest of approximately $20,000 from a
    preferred shareholder (see Note 7). In conjunction with this issuance, the
    Company issued warrants to purchase 1,312,500 shares of the Company's common
    stock at $0.80 per share. The Company has allocated approximately $292,000
    of the purchase price of the Series B Convertible Preferred Stock as the
    value of these warrants.

    In April 1998, the Company issued 156,250 shares of the Company's Series C
    Convertible Preferred Stock and warrants to purchase 187,500 shares of the
    Company's common stock at $1.60 per share for an aggregate purchase price of
    $1.5 million. The Company has allocated approximately $75,000 of the
    purchase price of the Series C Convertible Preferred Stock as the value of
    the warrants issued. On February 1, 1999 these warrants were exercised.
    Shares of the Company's Series C Convertible Preferred Stock are
    non-cumulative and convertible into six shares of the Company's common
    stock, subject to the occurrence of certain events provided for in the
    Company's amended and restated articles of incorporation. The shares are
    mandatorily convertible upon the completion of an initial

                                      F-14
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

8.  SHAREHOLDERS' EQUITY: (CONTINUED)
    public offering in which the per share price is equal to or exceeds $3.20
    and gross proceeds equal or exceed $8.0 million, or when two-thirds of the
    Series C Convertible Preferred shares have been converted. The holders of
    the Series C Convertible Preferred Stock have certain voting rights and
    liquidation preferences equal to $9.60 per share.

    In August 1998, the Company issued 1,138,438 shares of Series D Redeemable
    Convertible Preferred Stock for an aggregate purchase price of approximately
    $7.7 million. Holders of the Company's Series D Redeemable Convertible
    Preferred Stock are entitled to receive an annual non-cumulative dividend of
    $0.68 per share, subject to declaration by the Board of Directors, at their
    sole discretion. The shares are convertible into two shares of the Company's
    Common Stock, subject to the occurrence of certain events provided for in
    the Company's amended and restated articles of incorporation. The shares are
    mandatorily convertible into common stock upon the completion of an initial
    public offering in which the per share price equals or exceeds $5.00 and
    gross proceeds are equal to or exceed $15.0 million. The Company is required
    to redeem all outstanding shares of the Series D Redeemable Convertible
    Preferred Stock at $6.79 per share, plus all declared and unpaid dividends,
    either in August 2005 or in three annual installments beginning August 2003
    at the request of holders of at least two-thirds of the outstanding Series D
    Redeemable Convertible Preferred Stock. The holders of the Series D
    Redeemable Convertible Preferred Stock have certain voting rights and
    liquidation preferences equal to $13.58 per share.

    B.  COMMON STOCK

    The Company issued 5,388,000 shares of common stock on February 26, 1996,
    the date of its incorporation. In conjunction with the Company's formation
    it entered into a merger with Ambiente Inc. ("Ambiente") which was
    consummated in March 1996. Pursuant to the merger agreement, the Company
    issued 612,000 shares of common stock to the shareholders of Ambiente.
    Through the date of the merger, Ambiente had no significant operations,
    assets or liabilities, other than software under development that had not
    yet achieved technological feasibility. Accordingly, no value was assigned
    to the stock issued.

    On December 2, 1996 and January 27, 1999 the Company authorized a 3 for 1
    and 2 for 1 stock split, in the form of stock dividends, respectively on the
    Company's common stock. All references to number of shares and per share
    amounts of the Company's common stock in the accompanying financial
    statements and notes have been restated to reflect these stock splits.

    Upon incorporation of the Company, the founding shareholders entered into an
    agreement (as amended, the "Shareholder Agreement") which, among other
    things, called for a mandatory offer to sell the shareholders' stock, first
    to the remaining founders, then to the Company, in the event of termination
    of their employment with the Company. In February 1998, one of the founders,
    who was also an officer of the Company, and the Company purchased 2,600,000
    shares of the Company's common stock under the Shareholder Agreement from
    two founders who had terminated their employment. The Company facilitated
    the transactions between the shareholders under the Shareholder Agreement,
    retaining 800,000 of the repurchased shares.

    In February 1999, the Company issued a warrant to purchase up to 12,500
    shares of the Company's common stock at $8.00 per share to a certain
    customer in conjunction with a sale of products.

                                      F-15
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

8.  SHAREHOLDERS' EQUITY: (CONTINUED)
    C.  INITIAL PUBLIC OFFERING

    On June 4, 1999, the Company issued 2,860,000 shares of its common stock at
    an initial public offering price of $10.00 per share. Also sold in this
    offering were 590,000 shares held by selling shareholders, including 450,000
    shares sold upon the exercise of the underwriters' overallotment option. The
    net proceeds to the Company from the offering, net of offering costs of
    approximately $3.1 million were approximately $25.5 million. Concurrent with
    the initial public offering, each outstanding share of the Company's
    convertible preferred stock was automatically converted into common stock.

    The Company has issued warrants to purchase common stock to investors and to
    a certain customer. The aggregate consideration for each respective
    transaction was allocated to securities or debt and the warrants based on
    their relative fair values. All the warrants were exercisable at the time of
    issuance. The assumptions applied in the determination of the fair value of
    warrants issued were (i) use of the Black-Scholes pricing model, (ii) risk
    free interest rates ranging from 5.2% to 6.2%, (iii) expected volatility
    rates of approximately 70% (based on disclosed expected volatility rates of
    comparable companies) and actual volatility subsequent to the initial public
    offering, (iv) assumed expected lives of 4 to 10 years, and (v) no expected
    dividends.

    At June 30, 1999, warrants outstanding were as follows:

<TABLE>
<CAPTION>
                                                                                                AGGREGATE
WARRANT TO                                                          SHARES OF      EXERCISE      EXERCISE
PURCHASE                                                           COMMON STOCK      PRICE        PRICE
- ----------------------------------------------------------------  --------------  -----------  ------------
<S>                                                               <C>             <C>          <C>
Common stock....................................................        100,000    $    0.64   $     64,000
Common stock....................................................        600,000         0.50        300,000
Common stock....................................................      1,500,000         0.80      1,200,000
Common stock....................................................         12,500         8.00        100,000
                                                                  --------------               ------------
                                                                      2,212,500                $  1,664,000
                                                                  --------------               ------------
                                                                  --------------               ------------
</TABLE>

    D.  EQUITY INCENTIVE PLANS

    In January 1997, Company's shareholders approved the Amended and Restated
    1996 Stock Option Plan (the "1996 Employee Plan") that provides for
    discretionary grants of non-qualified and incentive stock options for
    employees and other service providers, and the Amended and Restated
    Directors' Nonqualified Stock Option Plan (the "1996 Directors' Plan"),
    which provides for automatic grants of non-qualified stock options to
    eligible non-employee directors. A total of 2,600,000 shares of common stock
    has been reserved for issuance under the 1996 Employee Plan and the 1996
    Directors' Plan. Employees' stock options typically vest over a period of
    four years from the grant date; director options typically vest over a
    period of three years from the grant date. All options under the 1996
    Employee Plan and the 1996 Directors' Plan expire 10 years after the grant
    date. In August 1997, the Company repriced all existing employee options to
    an exercise price of $0.05 per share. This repricing was accounted for as a
    cancellation of existing stock options and grant of new stock options. All
    outstanding, unvested options under the 1996 Employee Plan and the 1996
    Director's Plan vest in full upon a change in control of the Company. The
    Company does not intend to grant any additional options under either of
    these Plans.

                                      F-16
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

8.  SHAREHOLDERS' EQUITY: (CONTINUED)
    In November 1998, the Company's shareholders adopted the 1998 Equity
    Incentive Plan (the "1998 Plan"), which provides for discretionary grants of
    non-qualified and incentive stock options, stock purchase awards and stock
    bonuses for employees and other service providers. A total of 800,000 shares
    of common stock have been reserved for issuance under the 1998 Plan. Stock
    options granted under this plan typically vest over a period of four years
    from the grant date, and expire 10 years from the grant date. The Company
    has not granted any stock purchase awards or stock bonuses under the 1998
    Plan. Upon certain changes in control of the Company, the surviving entity
    will either assume or substitute all outstanding options or stock awards
    under the 1998 Plan. If the surviving entity determines not to assume or
    substitute such options or awards, then with respect to persons whose
    service with the Company or an affiliate of the Company has not terminated
    before a change in control, the vesting of 50% of these options or stock
    awards (and the time during which these awards may be exercised) will
    accelerate and the options or awards terminated if not exercised before the
    change in control.

    The Company applies the accounting provisions prescribed in APB No. 25 and
    related interpretations. In certain instances, the Company has issued stock
    options with an exercise price less than the deemed fair value of the
    Company's common stock at the date of grant. Accordingly, total compensation
    costs related to these stock options of approximately $238,000 and $1.9
    million was deferred during fiscal years 1997 and 1998, respectively, and
    $1.1 million and $4.1 million for the nine months ended June 30, 1998
    (unaudited) and 1999, respectively, and is being amortized over the vesting
    period of the options, generally four years. Amortization of unearned
    compensation costs of approximately $4,000 has been recognized as an expense
    for the period from February 26, 1996 (inception) to September 30, 1996,
    $69,000 and $420,000 for the years ended September 30, 1997 and 1998,
    respectively. Amortization of unearned compensation amounted to $205,000 and
    $1.8 million for the nine months ended June 30, 1998 (unaudited) and 1999,
    respectively.

                                      F-17
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

8.  SHAREHOLDERS' EQUITY: (CONTINUED)
    A summary of stock option transactions are as follows:

<TABLE>
<CAPTION>
                                                                                             WEIGHTED
                                                                                              AVERAGE
                                                                             OUTSTANDING  EXERCISE PRICE
                                                                               OPTIONS       PER SHARE
                                                                             -----------  ---------------
<S>                                                                          <C>          <C>
Inception
Options granted............................................................    1,146,000     $    0.38
Options canceled...........................................................     (150,000)         0.34
                                                                             -----------
Balances at September 30, 1996.............................................      996,000          0.38

Options granted............................................................    1,349,000          0.15
Options canceled...........................................................   (1,119,000)         0.36
                                                                             -----------
Balances at September 30, 1997.............................................    1,226,000          0.15

Options granted............................................................    1,543,000          0.29
Options exercised..........................................................     (215,750)         0.11
Options canceled...........................................................     (476,000)         0.11
                                                                             -----------
Balances at September 30, 1998.............................................    2,077,250          0.26

Options granted............................................................    1,171,121          3.53
Options exercised..........................................................     (684,809)         1.36
Options canceled...........................................................     (194,300)         1.09
                                                                             -----------
Balances at June 30, 1999..................................................    2,369,262          1.50
                                                                             -----------
                                                                             -----------
</TABLE>

    Pro forma information regarding net loss is required by SFAS No. 123, and
    has been determined as if the Company had accounted for its stock options
    under the minimum value method of that statement. The fair value of each
    option is estimated at the date of grant with the following weighted-average
    assumptions used for grants issued for the period from February 26, 1996
    (inception) to September 30, 1996, for the years ended September 30, 1997
    and 1998, and for the nine months ended June 30, 1999:

<TABLE>
<CAPTION>
                                                         PERIOD FROM
                                                        FEBRUARY 26,
                                                            1996       YEAR ENDED SEPTEMBER  NINE MONTHS
                                                         (INCEPTION)           30,              ENDED
                                                        TO SEPTEMBER   --------------------    JUNE 30,
                                                          30, 1996       1997       1998         1999
                                                        -------------  ---------  ---------  ------------
<S>                                                     <C>            <C>        <C>        <C>
Risk-free interest rate...............................        6.21%        6.21%      4.62%        5.47%

Dividend yield........................................        0.00%        0.00%      0.00%        0.00%

Expected term of option...............................      4 years      4 years    4 years      4 years

Volatility subsequent to initial public offering......                                            69.87%
</TABLE>

                                      F-18
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

8.  SHAREHOLDERS' EQUITY: (CONTINUED)
    For purposes of pro forma disclosures, the estimated fair value of the
    options is amortized over the options' vesting period. The Company's net
    loss would have been as indicated in the pro forma table below:

<TABLE>
<CAPTION>
                                                   PERIOD FROM
                                                  FEBRUARY 26,
                                                      1996        YEAR ENDED SEPTEMBER
                                                 (INCEPTION) TO           30,            NINE MONTHS ENDED
                                                  SEPTEMBER 30,   --------------------       JUNE 30,
                                                      1996          1997       1998            1999
                                                 ---------------  ---------  ---------  -------------------
                                                         (IN THOUSANDS, EXCEPT
                                                            PER SHARE DATA)
<S>                                              <C>              <C>        <C>        <C>
Net loss--as reported..........................     $    (330)    $  (1,456) $  (3,672)      $  (6,678)

Net loss--pro forma............................          (331)       (1,468)    (3,742)         (7,057)

Net loss per share--as reported................         (0.06)        (0.24)     (0.60)          (0.88)

Net loss per share--pro forma..................         (0.06)        (0.24)     (0.61)          (0.93)
</TABLE>

    The weighted-average fair values and weighted-average exercise prices per
    share at the date of grant for options granted during the period from
    February 26, 1996 (inception) to September 30, 1996, for the years ended
    September 30, 1997 and 1998 and for the nine months ended June 30, 1999 were
    as follows:

<TABLE>
<CAPTION>
                                                     PERIOD FROM
                                                    FEBRUARY 26,
                                                        1996        YEAR ENDED SEPTEMBER
                                                   (INCEPTION) TO           30,             NINE MONTHS
                                                    SEPTEMBER 30,   --------------------  ENDED JUNE 30,
                                                        1996          1997       1998          1999
                                                   ---------------  ---------  ---------  ---------------
<S>                                                <C>              <C>        <C>        <C>
Weighted-average fair value of options granted
  with exercise prices equal to the market value
  of the stock at the date of grant..............     $    0.01     $    0.01  $    0.08     $    2.79

Weighted-average exercise price of options
  granted with exercise prices equal to the
  market value of the stock at the date of
  grant..........................................          0.05          0.05       0.50         10.32

Weighted-average fair value of options granted
  with exercise prices less than the market value
  of the stock at the date of grant..............                        0.41       1.60          4.54

Weighted-average exercise price of options
  granted with exercise prices less than the
  market value of the stock at the date of
  grant..........................................          0.05          0.05       0.28          1.13
</TABLE>

                                      F-19
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

8.  SHAREHOLDERS' EQUITY: (CONTINUED)
    The following table summarizes information about fixed-price options
    outstanding at June 30, 1999 as follows:

<TABLE>
<CAPTION>
                               WEIGHTED
                                AVERAGE      WEIGHTED                  WEIGHTED
                               REMAINING      AVERAGE                   AVERAGE
   EXERCISE       NUMBER      CONTRACTUAL    EXERCISE      NUMBER     EXERCISABLE
    PRICES      OUTSTANDING      LIFE          PRICE     EXERCISABLE     PRICE
- --------------  -----------  -------------  -----------  -----------  -----------
<S>             <C>          <C>            <C>          <C>          <C>
    $0.05          751,096          8.28     $    0.05       33,001    $    0.05
  $0.25-0.50       472,449          8.58     $    0.32      112,700    $    0.44
  $0.75-1.50       841,544          9.33     $    1.21       94,002    $    1.15
  $2.50-5.00       108,000          9.62     $    3.14          833    $    2.50
 $8.00-10.00       174,348          9.83     $    9.15          967    $    8.11
 $15.50-18.63       14,200          9.96     $   16.71        5,000    $   18.00
 $19.38-27.88        7,625          9.97     $   21.76
</TABLE>

    1999 EMPLOYEE STOCK PURCHASE PLAN

    In May 1999, the board of directors approved the adoption of the 1999
    Employee Stock Purchase Plan (the "Purchase Plan"). A total of 1,000,000
    shares of common stock has been reserved for issuance under the Purchase
    Plan. The Purchase Plan permits eligible employees to acquire shares of the
    Company's common stock through periodic payroll deductions of up to 15% of
    base compensation. No employee may purchase more than $25,000 worth of
    stock, determined at the fair market value of the shares at the time such
    option is granted, in one calendar year. The Purchase Plan will be
    implemented in a series of offering periods, each approximately 6 months in
    duration; provided, however, that the first offering period commenced on the
    effectiveness of the initial public offering and be approximately seven
    months in duration, ending on the last trading day on or before December 31,
    1999. The price at which the common stock may be purchased is 85% of the
    lesser of the fair market value of the Company's common stock on the first
    day of the applicable offering period or on the last day of the respective
    purchase period.

9.  COMMITMENTS:

    The Company is committed under non-cancelable operating leases for its
    current and former office space, which expire in 2002 and 1999,
    respectively. During 1998, the Company leased its former office space under
    a non-cancelable sub-leasing arrangement for amounts equal to the liability
    of the commitment, which expires in 1999. Additionally, the Company is
    committed under non-cancelable

                                      F-20
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

9.  COMMITMENTS: (CONTINUED)
    operating leases for certain office equipment. Minimum operating lease
    payments and sub-leasing receipts for future fiscal years, as of June 30,
    1999, are approximately as follows:

<TABLE>
<CAPTION>
                                                              OPERATING LEASE   OPERATING SUBLEASE
                                                                 PAYMENTS            RECEIPTS
                                                              ---------------   ------------------
                                                                         (IN THOUSANDS)
<S>                                                           <C>               <C>
1999........................................................      $  345               $18
2000........................................................         537
2001........................................................         587
2002........................................................         618
Thereafter..................................................       1,134
                                                                                        --
                                                                  ------
                                                                  $3,221               $18
                                                                                        --
                                                                                        --
                                                                  ------
                                                                  ------
</TABLE>

    Rent expense under noncancelable operating leases amounted to approximately
    $7,000 for the period from February 26, 1996 (inception) to September 30,
    1996, approximately $38,000 and $145,000 for the years ended September 30,
    1997 and 1998, respectively. Rent expense amounted to approximately $98,000
    and $308,000 for the nine months ended June 30, 1998 (unaudited) and 1999,
    respectively.

10.  RELATED PARTY TRANSACTIONS:

    In March 1999, the Company issued 150,000 shares of common stock to an
    officer of the Company in exchange for a note receivable. These shares were
    acquired by exercising stock options that vest over a period of four years.
    The note bears interest at a rate of 4.83%, is collateralized by the shares,
    partially guaranteed by the officer and is due in 2003. Under the pledge
    agreement, the Company has the obligation to repurchase any remaining
    unvested shares, and the note becomes due upon the officer's termination.
    Further, the shares may not be transferred until they are vested and paid
    for.

11.  SUBSEQUENT EVENTS

    In September 1999, the Board of Directors authorized management of the
    Company to file a Registration Statement with the Securities and Exchange
    Commission covering the proposed sale of additional shares of its common
    stock to the public.

    In July of 1999 the Company amended their existing lease of office space to
    add an additional 8,000 square feet, for a term of 84 months. The annual
    cost of this additional lease is approximately $164,000, subject to annual
    adjustments. Also in July of 1999 the Company entered into a new lease for
    approximately 84,000 square feet of office space in a building which is
    currently under construction. This lease will commence in July 1, 2000 with
    a term of 12 years. The annual cost of this lease is approximately
    $2,000,000, subject to annual adjustments. Also in July 1999, the Company
    entered into an outstanding secured irrevocable letter of credit with a bank
    in the amount of $2.5 million which collateralizes the Company's obligation
    to fund its lease commitment.

                                      F-21
<PAGE>
                               F5 NETWORKS, INC.

                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)

12.  SUPPLEMENTAL CASH FLOW INFORMATION:

    Supplemental disclosure of cash flow information is summarized below for the
    years ended September 30, 1997 and 1998, for the period from February 26,
    1996 (inception) to September 30, 1996, and for the nine months ended June
    30, 1998 (unaudited) and 1999:

<TABLE>
<CAPTION>
                                                                  PERIOD FROM
                                                                 FEBRUARY 26,                                 NINE MONTHS
                                                                     1996             YEAR ENDED                 ENDED
                                                                  (INCEPTION)        SEPTEMBER 30,             JUNE 30,
                                                                 TO SEPTEMBER    ---------------------   ---------------------
                                                                   30, 1996         1997        1998       1998        1999
                                                                 -------------     -----      --------   ---------   ---------
                                                                                        (IN THOUSANDS)
<S>                                                              <C>             <C>          <C>        <C>         <C>
                                                                                                         (UNAUDITED)
Noncash investing and financing activities:
  Equipment obtained through capital lease.....................       $43           $    11
  Disposal of property and equipment for note and relief of
    accounts payable...........................................        10
  Deferred gain on sale leaseback..............................         5
  Series A Convertible Preferred Stock issued for note.........        90
  Conversion of note payable and related accrued interest to
    Series B Convertible
    Preferred Stock............................................                                   $520     $520
  Value ascribed to warrants in conjunction with sale of
    Convertible Preferred Stock................................                          42        367      367
  Value ascribed to warrants issued with note payable..........                         109
  Conversion of note payable to common stock...................                                    209      209
  Note receivable from shareholder for exercise of options.....                                                         $750
  Unearned compensation........................................         4               238      1,945    1,098       4,063
  Write-off of accounts receivable.............................                                     30       30          78
  Sales returns................................................                                    193      117         556
Cash paid for interest.........................................                          19         30       16           2
</TABLE>

                                      F-22
<PAGE>
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------

                                2,200,000 SHARES

                                     [LOGO]

                                  COMMON STOCK
                                 -------------

                                   PROSPECTUS

                                 -------------

                               HAMBRECHT & QUIST

                         BANCBOSTON ROBERTSON STEPHENS

                            BEAR, STEARNS & CO. INC.

                              DAIN RAUSCHER WESSELS
                                A DIVISION OF DAIN RAUSCHER INCORPORATED

                               ------------------

                               September 30, 1999

                               ------------------

    YOU SHOULD RELY ONLY ON 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 THIS
PROSPECTUS OR OF ANY SALE OF OUR COMMON STOCK.

    NO ACTION IS BEING TAKEN IN ANY JURISDICTION OUTSIDE THE UNITED STATES TO
PERMIT A PUBLIC OFFERING OF THE COMMON STOCK OR POSSESSION OR DISTRIBUTION OF
THIS PROSPECTUS IN ANY SUCH JURISDICTION. PERSONS WHO COME INTO POSSESSION OF
THIS PROSPECTUS IN JURISDICTIONS OUTSIDE THE UNITED STATES ARE REQUIRED TO
INFORM THEMSELVES ABOUT AND TO OBSERVE ANY RESTRICTIONS AS TO THIS OFFERING AND
THE DISTRIBUTION OF THIS PROSPECTUS APPLICABLE TO THAT JURISDICTION.

- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------


© 2022 IncJournal is not affiliated with or endorsed by the U.S. Securities and Exchange Commission