VIATEL INC
S-3, 1999-05-20
TELEPHONE COMMUNICATIONS (NO RADIOTELEPHONE)
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<PAGE>
      AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MAY 20, 1999
 
                                                      REGISTRATION NO. 333-
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                            ------------------------
 
                                    FORM S-3
 
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                             ---------------------
 
                                  VIATEL, INC.
 
             (Exact Name of Registrant as Specified in its Charter)
 
<TABLE>
<S>                                                          <C>
                         DELAWARE                                                    13-3787366
              (State or Other Jurisdiction of                                     (I.R.S. Employer
              Incorporation or Organization)                                   Identification Number)
</TABLE>
 
                                685 THIRD AVENUE
                            NEW YORK, NEW YORK 10017
                                 (212) 350-9200
         (Address, Including Zip Code, and Telephone Number, Including
            Area Code, of Registrant's Principal Executive Offices)
                         ------------------------------
 
       SHELDON M. GOLDMAN, ESQ.
        SENIOR VICE PRESIDENT,
 BUSINESS AFFAIRS AND GENERAL COUNSEL
             VIATEL, INC.
           685 THIRD AVENUE
       NEW YORK, NEW YORK 10017
            (212) 350-9200
 (Name, Address, Including Zip Code,
            and Telephone
Number, Including Area Code, of Agent
             For Service)
 
                        COPIES OF ALL COMMUNICATIONS TO:
 
<TABLE>
<S>                                                          <C>
                  JAMES P. PRENETTA, ESQ.                                     JAMES S. SCOTT, SR., ESQ.
                 KELLEY DRYE & WARREN LLP                                        SHEARMAN & STERLING
                      101 PARK AVENUE                                           599 LEXINGTON AVENUE
                 NEW YORK, NEW YORK 10178                                     NEW YORK, NEW YORK 10022
                      (212) 808-7800                                               (212) 848-4000
</TABLE>
 
                         ------------------------------
 
    APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: As soon as
practicable after the registration statement becomes effective.
 
    If the only securities being registered on this Form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box.  / /
 
    If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, other than securities offered only in connection with dividend or interest
reinvestment plans, check the following box.  / /
 
    If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering.  / / ____________
 
    If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering.  / /
 
    If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box.  / /
                         ------------------------------
 
                        CALCULATION OF REGISTRATION FEE
 
<TABLE>
<CAPTION>
                                                                   PROPOSED MAXIMUM    PROPOSED MAXIMUM       AMOUNT OF
           TITLE OF SHARES TO BE                 AMOUNT TO BE      AGGREGATE PRICE    AGGREGATE OFFERING     REGISTRATION
                 REGISTERED                     REGISTERED(1)         PER SHARE            PRICE(2)              FEE
<S>                                           <C>                 <C>                 <C>                 <C>
Common Stock, par value $.01 per share......   5,405,000 Shares        $45.625           $246,603,125         $68,555.67
</TABLE>
 
(1) Includes 705,000 shares subject to an over-allotment option granted to the
    Underwriters.
 
(2) Estimated solely for the purpose of calculating the registration fee in
    accordance with Rule 457(c) under the Securities Act of 1933, as amended.
    The Proposed Maximum Aggregate Price Per Share is estimated on the basis of
    the average of the high and low trading prices for Viatel, Inc.'s Common
    Stock on May 14, 1999, as reported by the Nasdaq National Market.
                         ------------------------------
 
    THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF
THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(A),
MAY DETERMINE.
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>
THE INFORMATION IN THIS PROSPECTUS IS NOT COMPLETE AND MAY BE CHANGED. WE MAY
NOT SELL THESE SECURITIES UNTIL THE REGISTRATION STATEMENT FILED WITH THE
SECURITIES AND EXCHANGE COMMISSION IS EFFECTIVE. THIS PROSPECTUS IS NOT AN OFFER
TO SELL THESE SECURITIES AND WE ARE NOT SOLICITING OFFERS TO BUY THESE
SECURITIES IN ANY STATE WHERE THE OFFER OR SALE IS NOT PERMITTED.
<PAGE>
PROSPECTUS (SUBJECT TO COMPLETION)
 
ISSUED MAY 20, 1999
 
                                4,700,000 SHARES
 
                                 [VIATEL LOGO]
 
                                  COMMON STOCK
 
                               -----------------
 
VIATEL, INC. IS OFFERING 4,000,000 SHARES AND THE SELLING STOCKHOLDERS ARE
OFFERING 700,000 SHARES.
 
                              -------------------
 
VIATEL, INC.'S COMMON STOCK IS LISTED ON THE NASDAQ NATIONAL MARKET UNDER THE
SYMBOL "VYTL." ON MAY 19, 1999, THE REPORTED LAST SALE PRICE OF THE COMMON STOCK
ON THE NASDAQ NATIONAL MARKET WAS $52 1/8 PER SHARE.
 
                              -------------------
 
INVESTING IN THE COMMON STOCK INVOLVES RISKS. SEE "RISK FACTORS" BEGINNING ON
PAGE 9.
 
                              -------------------
 
                               PRICE $   A SHARE
 
                              -------------------
 
<TABLE>
<CAPTION>
                                                       UNDERWRITING                            PROCEEDS TO
                                     PRICE TO         DISCOUNTS AND        PROCEEDS TO           SELLING
                                      PUBLIC           COMMISSIONS            VIATEL           STOCKHOLDERS
                                ------------------  ------------------  ------------------  ------------------
<S>                             <C>                 <C>                 <C>                 <C>
PER SHARE.....................          $                   $                   $                   $
TOTAL.........................          $                   $                   $                   $
</TABLE>
 
                              -------------------
 
THE SECURITIES AND EXCHANGE COMMISSION AND STATE SECURITIES REGULATORS HAVE NOT
APPROVED OR DISAPPROVED THESE SECURITIES, OR DETERMINED IF THIS PROSPECTUS IS
TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.
 
VIATEL, INC. AND ONE OF THE SELLING STOCKHOLDERS HAVE GRANTED THE UNDERWRITERS
THE RIGHT TO PURCHASE UP TO AN ADDITIONAL 705,000 SHARES TO COVER
OVER-ALLOTMENTS. MORGAN STANLEY & CO. INCORPORATED EXPECTS TO DELIVER THE SHARES
TO PURCHASERS ON            , 1999.
 
                              -------------------
 
                           MORGAN STANLEY DEAN WITTER
 
            , 1999
<PAGE>
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                                                                               PAGE
                                                                                                             ---------
<S>                                                                                                          <C>
Prospectus Summary.........................................................................................          3
Risk Factors...............................................................................................          9
Disclosure Regarding Forward Looking Statements............................................................         20
Use of Proceeds............................................................................................         21
Dilution...................................................................................................         21
Price Range of Our Common Stock............................................................................         22
Dividend Policy............................................................................................         23
Capitalization.............................................................................................         23
Selected Consolidated Financial Data.......................................................................         24
Management's Discussion and Analysis of Financial Condition and Results of Operations......................         26
Business...................................................................................................         38
Management.................................................................................................         59
Certain Transactions.......................................................................................         68
Principal and Selling Stockholders.........................................................................         69
Description of Capital Stock...............................................................................         70
Certain United States Tax Consequences for Non-U.S. Investors..............................................         73
Underwriters...............................................................................................         75
Legal Matters..............................................................................................         78
Experts....................................................................................................         78
Where You Can Find More Information About Us...............................................................         78
Index to Consolidated Financial Statements.................................................................        F-1
</TABLE>
 
                            ------------------------
 
    You should rely only on the information contained in this prospectus. We
have not authorized anyone to provide you with information different from that
contained in this prospectus. This prospectus is not an offer to sell the common
stock and it is not soliciting an offer to buy common stock in any state where
the offer or sale is not 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 the common stock.
 
    Our principal executive offices are located at 685 Third Avenue, New York,
New York 10017. Our telephone number at this location is (212) 350-9200.
 
                            ------------------------
 
    VIACALL, VIACALL Plus, VIACALL Express, VIAPN, VIAISDN, VIAGLOBE and
VIAWORLDFAX are marketed under a number of service marks; VIADIRECT, VIADIRECT
Plus, VIALINK and VIA0800 are marketed under a number of pending service marks;
and Viatel uses various registered logos including "Viatel," a federally
registered service mark in the United States.
 
                                       2
<PAGE>
                               PROSPECTUS SUMMARY
 
    THIS SUMMARY HIGHLIGHTS SELECTED INFORMATION FROM THIS PROSPECTUS AND MAY
NOT CONTAIN ALL THE INFORMATION THAT IS IMPORTANT TO YOU. FOR A MORE COMPLETE
UNDERSTANDING OF VIATEL AND THE SHARES OF COMMON STOCK OFFERED BY THIS
PROSPECTUS, YOU SHOULD READ THE ENTIRE PROSPECTUS, INCLUDING THE CONSOLIDATED
FINANCIAL STATEMENTS AND ACCOMPANYING NOTES, AND THE RISK FACTORS.
 
                                  THE COMPANY
 
OVERVIEW
 
    We are a rapidly growing international communications company providing high
quality, competitively priced, long distance communication and data services to
end users, carriers and resellers. Our revenue has grown from $32.3 million in
1995 to $135.2 million in 1998, and today we have direct sales forces in twelve
Western European cities and an indirect sales force in more than 180 locations
in Western Europe.
 
    To capitalize on the opportunities presented by deregulation of the
telecommunications industry in Western Europe, we established an early presence
and sought aggressively to acquire licenses, interconnection and infrastructure.
Today, we have licenses in Belgium, France, Germany, Italy, The Netherlands and
the United Kingdom and interconnection agreements with the incumbent
telecommunications operator in each of these countries. We also have licenses in
Spain and Switzerland and expect to obtain interconnection agreements in these
countries during the fourth quarter of 1999.
 
    We currently operate one of Europe's largest pan-European networks, with
points of presence in 45 cities. We believe that control of network
infrastructure is critical to becoming a high quality, low-cost provider of
communications services because it will enable us to better manage service
offerings, quality of transmission and costs. Accordingly, we are currently in
the process of migrating from a network composed of international and domestic
leased circuits to a network composed primarily of owned circuits. To facilitate
this transition, in 1998 we commenced construction of a five-ring fiber optic
network in the largest telecommunications markets in Europe. These five rings,
which are expected to consist of approximately 8,700 route kilometers, comprise
the "Circe Network." In March 1999, we completed construction of phase one of
the Circe Network, which connects five European countries and includes London,
Paris, Amiens, Brussels, Antwerp, Rotterdam and Amsterdam, and have begun
construction of phases two and three.
 
    We believe, and our experience to date has indicated, that demand from end
users, carriers and other communications companies for high quality transmission
capacity in Europe will increase over the next several years due to fundamental
changes in the communications industry brought about by regulatory and technical
improvements. We also believe that cost effective transmission capacity in
Europe will allow new capacity intensive applications to be created which will,
in turn, fuel the need for capacity. Our network should allow us to meet this
increased demand by providing abundant transmission capacity for these
applications as well as for the continued growth in our existing voice service
business.
 
    As part of our strategy to capture a share of the rapidly growing data
market, in the first quarter of 1999 we entered into an arrangement with Lucent
Technologies, Inc. pursuant to which Lucent is installing asynchronous transfer
mode backbone network equipment on our Circe Network. This backbone equipment is
designed to enable us to provide packet switched voice, video conferencing,
private intranets and dedicated Internet protocol transport over an integrated
platform and offer end users high capacity, speed and reliability. Lucent has
agreed to cooperate with us in developing marketing strategies to promote our
data services, to train our personnel and to assist us in achieving
network-to-network interfaces with certain specified carriers. We expect our
data network to be commercially operable in the fourth quarter of 1999.
 
                                       3
<PAGE>
THE CIRCE NETWORK
 
    The Circe Network is a series of state-of-the-art, high quality, high
capacity, self-healing rings, utilizing advanced synchronous digital hierarchy,
the current international standard for digital transmission, and dense wave
division multiplexing technology.
 
    As currently planned, the Circe Network will be comprised of five
interlocking, bi-directional rings, consisting of approximately 8,700 route
kilometers of fiber optic cable. The first phase of the Circe Network,
consisting of approximately 1,850 route kilometers (including 312 route
kilometers of undersea fiber optic cable) was placed into operation during the
first half of March. The second phase, which will extend through northern
France, The Netherlands and into western Germany, is scheduled to be placed into
service during the third quarter of 1999. The third phase, which will extend
through eastern Germany, is scheduled to be placed into service during the first
quarter of 2000. We currently anticipate that the fourth and fifth phases of the
Circe Network, which will extend into southern France and Switzerland, will be
completed during the second quarter of 2000.
 
    The Circe Network offers incumbent telecommunications operators and new
entrants a compelling, cost-effective, high quality, alternative for the
transport of European cross-border telecommunications traffic. Under the
traditional system of carrying cross-border telecommunications traffic in
Europe, the incumbent telecommunications operators did not develop end-to-end
cross-border circuits, but rather connected their national networks with other
carriers at the border. The Circe Network's cross-border transport will offer
consistently high transmission quality at reduced cost.
 
    Key characteristics of the Circe Network include:
 
    - STATE-OF-THE-ART TECHNOLOGY. The Circe Network uses a laser-generated
      light to transmit information bi-directionally over fiber optic glass
      strands at an initial capacity of 20 gigabits per second. In addition, the
      Circe Network employs dense wave division multiplexing technology. This
      technology allows more discrete wavelengths of light to be transmitted
      through fiber, thereby permitting the transfer of greater amounts of
      information at a lower cost than was achievable with prior fiber optic
      technology.
 
    - UNIFORM NETWORK ARCHITECTURE. The entire Circe Network will consist of a
      single uniform configuration of Nortel Telecom's optronics and Lucent's
      fiber optic cable, thereby enhancing service quality while improving
      efficiency and lowering costs.
 
    - SECURE AND RELIABLE. The Circe Network is being designed to provide high
      security and reliability by employing such features as two redundant
      network operating centers and a self-healing architecture to allow for
      instantaneous restoration in the event of a single fiber cut.
 
    - SCALABLE AND FLEXIBLE. The Circe Network's high density network
      architecture may be upgraded, without service interruptions, to at least
      320 gigabits per second per fiber pair through the use of dense wave
      division multiplexing technology, to support demand for bandwidth
      intensive data applications. We anticipate that each ring of the Circe
      Network will contain at least 48 fibers.
 
BUSINESS STRATEGY
 
    Our goal is to become a fully integrated communications company that is well
positioned to take advantage of growth opportunities in the European
communications industry. We believe that we can accomplish this goal by becoming
a low-cost provider of services through the ownership of network infrastructure.
The key elements of our strategy include:
 
    - CAPITALIZE ON DEREGULATION IN LARGE EUROPEAN MARKETS.  Our principal focus
      is on exploiting both international and national long distance
      opportunities presented by rapidly deregulating European markets. In 1997,
      according to industry sources, the European international long distance
      market for voice services was the largest in the world, with approximately
      35 billion minutes of use.
 
                                       4
<PAGE>
      According to industry sources, Europe's volume of international minutes
      grew approximately 12% from 1996 to 1997. Industry sources estimate the
      European wholesale and retail market for all Internet services was $1.9
      billion in revenue for 1997.
 
    - LEVERAGE ESTABLISHED MARKET PRESENCE AND LOCAL DISTRIBUTION NETWORK.  We
      established an early presence in Western Europe to capitalize on the
      opportunities presented by deregulation of the telecommunications
      industry. As a result, we gained substantial experience in the
      operational, technical, financial and logistical issues involved in
      operating a network and building a sales force in Western Europe. We
      believe that our existing presence positions us to further capitalize on
      market opportunities in Western Europe.
 
    - FOCUS ON END USERS.  We have established a customer base of small and
      medium-sized businesses to which we currently sell long distance voice
      services. The Circe Network allows us to provide high quality services to
      these end users at competitive prices, particularly businesses with
      multiple offices and requiring significant capacity. Carrier preselection,
      scheduled for the year 2000 for most countries in the European Union, will
      enable us to capture a larger portion of our customers' telecommunications
      spending.
 
    - LEVERAGE CIRCE NETWORK THROUGH RESELLERS AND CARRIERS.  To efficiently use
      capacity on our network, we sell switched minutes to wholesale customers
      and other resellers. While we are constructing the Circe Network primarily
      for our own use, we also intend to sell switched minutes and to
      opportunistically sell excess capacity on the network, thus enhancing the
      utilization of our switched network and reducing our construction costs.
 
    - OFFER A COMPREHENSIVE RANGE OF COMMUNICATION SERVICES.  Historically, we
      have only offered voice and value-added services such as facsimile
      transmission. The Circe Network will significantly expand our ability to
      meet the growing demand for data services and to offer a comprehensive
      range of such services including Internet access and transmission, frame
      relay, asynchronous transfer mode and Internet protocol services, as well
      as private line and data center co-location services. All of these
      services are extremely capacity intensive, and the high cost of leased
      transmission capacity made it uneconomical to offer such services without
      owning our own network.
 
    - BECOME A LOW COST PROVIDER OF COMMUNICATIONS SERVICES.  We believe that
      ownership of our network is critical to becoming a low-cost provider of
      bundled communications services. In addition, network ownership will
      enable us to manage service offerings and transmission quality. To achieve
      this objective, we (1) have invested in points of presence and switches,
      (2) are in the process of constructing the Circe Network, and (3) have
      purchased and swapped for capacity on fiber optic cable systems in and
      between Western Europe and the U.S.
 
    - PURSUE ACQUISITIONS, INVESTMENTS AND STRATEGIC ALLIANCES.  In addition to
      systematically expanding through internal growth, in the future we intend
      to expand our services and network capabilities through acquisitions,
      investments and strategic alliances in order to lower termination costs
      and achieve desired economies of scale.
 
                                       5
<PAGE>
                                  THE OFFERING
 
<TABLE>
<S>                               <C>               <C>
Common stock offered by:
  Viatel........................  4,000,000 shares
  Selling stockholders..........    700,000 shares
                                  ----------------
    Total.......................  4,700,000 shares
                                  ----------------
                                  ----------------
Common stock offered in:
  U.S. offering.................  3,760,000 shares
  International offering........    940,000 shares
                                  ----------------
    Total.......................  4,700,000 shares
                                  ----------------
                                  ----------------
Common Stock to be outstanding          31,832,363
  after the offering............            shares
 
Over-allotment option...........    705,000 shares
 
Use of proceeds.................  To further develop and enhance Viatel's network and for
                                  working capital and general corporate purposes. See "Use
                                  of Proceeds."
 
Dividend Policy.................  We have not paid any dividends on our common stock and do
                                  not intend to pay dividends on our common stock in the
                                  foreseeable future. See "Dividend Policy."
 
Nasdaq National Market symbol...  VYTL
</TABLE>
 
- ------------------------
 
    As of May 13, 1999, we had 23,227,013 shares of common stock outstanding. On
May 14, 1999, all outstanding shares of Series A preferred stock and all
subordinated convertible debentures were converted into approximately 4,605,350
shares of common stock. As a result, prior to the offering we had approximately
27,832,363 shares of common stock outstanding.
 
    The total shares to be outstanding after this offering do not include (i)
shares of common stock to be issued upon exercise of the underwriters'
over-allotment option and (ii) outstanding options at May 17, 1999 to purchase a
total of approximately 3.1 million shares of common stock at prices ranging from
$.75 to $22.88, with a weighted average exercise price of $10.28 per share, and
an additional 1.0 million shares reserved for future grants under Viatel's stock
incentive plan.
 
                                       6
<PAGE>
                      SUMMARY CONSOLIDATED FINANCIAL DATA
 
    The following table sets forth our summary consolidated financial data. The
data does not present all of our financial information. You should read this
information together with the consolidated financial statements and the notes to
those statements appearing elsewhere in this prospectus and the information
under "Selected Consolidated Financial Data" and "Management's Discussion and
Analysis of Financial Condition and Results of Operations." The as adjusted
balance sheet information gives effect to the issuance and sale of the common
stock offered by this prospectus at an assumed initial offering price of $52.13
per share and the conversion of our outstanding shares of Series A preferred
stock and subordinated convertible debentures as if the conversion had occurred
as of March 31, 1999. Net loss per share is computed on the basis described in
the notes to our consolidated financial statements. EBITDA consists of earnings
before interest, income taxes, extraordinary loss, dividends on preferred stock
and depreciation and amortization. Capital additions for each period consist of
capital expenditures, the net increase in payables for property and equipment,
assets acquired under capital lease obligations and capitalized interest during
the period. Restricted securities represents government obligations purchased by
Viatel which secure the payment of certain interest payments on its outstanding
senior notes.
 
<TABLE>
<CAPTION>
                                                                                                     THREE MONTHS
                                                                    YEAR ENDED DECEMBER 31,        ENDED MARCH 31,
                                                                -------------------------------  --------------------
                                                                  1996       1997       1998       1998       1999
                                                                ---------  ---------  ---------  ---------  ---------
                                                                        (IN THOUSANDS, EXCEPT PER SHARE DATA)
<S>                                                             <C>        <C>        <C>        <C>        <C>
CONSOLIDATED STATEMENT OF OPERATIONS DATA:
Revenue:
Communication services revenue................................  $  50,419  $  73,018  $ 131,938  $  21,239  $  48,395
Capacity sales................................................         --         --      3,250         --     13,246
                                                                ---------  ---------  ---------  ---------  ---------
      Total revenue...........................................     50,419     73,018    135,188     21,239     61,641
Operating expenses:
  Cost of services and sales..................................     42,130     63,504    122,109     19,105     51,048
  Selling, general and administrative.........................     32,866     36,077     44,893      8,955     18,763
  Depreciation and amortization...............................      4,802      7,717     16,268      2,911      9,603
                                                                ---------  ---------  ---------  ---------  ---------
      Total operating expenses................................     79,798    107,298    183,270     30,971     79,414
                                                                ---------  ---------  ---------  ---------  ---------
Operating loss................................................    (29,379)   (34,280)   (48,082)    (9,732)   (17,773)
Interest income...............................................      1,852      3,686     28,259        510      6,828
Interest expense..............................................    (10,848)   (12,450)   (79,177)    (3,781)   (26,166)
                                                                ---------  ---------  ---------  ---------  ---------
Loss before extraordinary loss................................    (38,375)   (43,044)   (99,000)   (13,003)   (37,111)
  Extraordinary loss on debt prepayment.......................         --         --    (28,304)        --         --
                                                                ---------  ---------  ---------  ---------  ---------
Net loss......................................................    (38,375)   (43,044)  (127,304)   (13,003)   (37,111)
  Dividends on redeemable convertible preferred stock.........         --         --     (3,301)        --     (1,177)
                                                                ---------  ---------  ---------  ---------  ---------
Net loss attributable to common stockholders..................  $ (38,375) $ (43,044) $(130,605) $ (13,003) $ (38,288)
                                                                ---------  ---------  ---------  ---------  ---------
                                                                ---------  ---------  ---------  ---------  ---------
Loss per common share, basic and diluted:
  Before extraordinary item...................................  $   (2.47) $   (1.90) $   (4.44) $   (0.57) $   (1.65)
  From extraordinary item.....................................         --         --      (1.23)        --         --
                                                                ---------  ---------  ---------  ---------  ---------
Net loss attributable to common stockholders..................  $   (2.47) $   (1.90) $   (5.67) $   (0.57) $   (1.65)
                                                                ---------  ---------  ---------  ---------  ---------
                                                                ---------  ---------  ---------  ---------  ---------
Weighted average shares used in per share calculation:
  Basic and diluted...........................................     15,514     22,620     23,054     22,783     23,186
</TABLE>
 
                                       7
<PAGE>
 
<TABLE>
<CAPTION>
                                                                                                     THREE MONTHS
                                                                    YEAR ENDED DECEMBER 31,        ENDED MARCH 31,
                                                                -------------------------------  --------------------
                                                                  1996       1997       1998       1998       1999
                                                                ---------  ---------  ---------  ---------  ---------
                                                                        (IN THOUSANDS, EXCEPT PER SHARE DATA)
<S>                                                             <C>        <C>        <C>        <C>        <C>
OTHER FINANCIAL DATA:
EBITDA........................................................  $ (24,577) $ (26,563) $ (31,814) $  (6,821) $  (8,170)
Net cash used in operating activities.........................    (26,331)   (22,525)   (60,318)   (10,771)   (21,578)
Net cash provided by (used in) investing activities...........     (1,592)   (43,164)  (349,992)    16,455   (200,424)
Net cash provided by (used in) financing activities...........     94,772     11,286    729,035       (209)   351,655
Capital additions.............................................      9,800     40,214    220,903      2,716    161,590
 
OTHER OPERATING DATA:
Billable minutes (000s).......................................     62,249    140,918    383,875     52,418    270,808
Switches......................................................         13         14         15         14         15
Points of presence............................................         13         33         34         33         45
Route kilometers of owned intra-European fiber optic cable in
  operation...................................................         --         --         --         --      1,850
</TABLE>
 
<TABLE>
<CAPTION>
                                                                                               AS OF MARCH 31, 1999
                                                                                              ----------------------
                                                                                               ACTUAL    AS ADJUSTED
                                                                                              ---------  -----------
                                                                                                  (IN THOUSANDS)
<S>                                                                                           <C>        <C>
CONSOLIDATED BALANCE SHEET DATA:
Cash, cash equivalents and marketable securities............................................  $ 498,755   $ 695,061
Restricted cash equivalents and restricted marketable securities............................    229,796     229,796
Cash securing letters of credit for network construction....................................    121,239     121,239
Working capital.............................................................................    427,217     623,523
Property and equipment, net.................................................................    409,909     409,909
Intangible assets, net......................................................................     70,579      70,116
Total assets................................................................................  1,411,990   1,607,833
Long-term debt, excluding current installments..............................................  1,292,482   1,280,001
Redeemable convertible preferred stock......................................................     48,298          --
Stockholders' (deficiency) equity...........................................................   (184,370)     72,252
</TABLE>
 
                                       8
<PAGE>
                                  RISK FACTORS
 
    YOU SHOULD CAREFULLY CONSIDER THE FOLLOWING RISKS, WHICH ARE NOT LISTED IN
ORDER OF PRIORITY, BEFORE MAKING AN INVESTMENT DECISION. THE RISKS DESCRIBED
BELOW ARE NOT THE ONLY ONES THAT WE FACE. OUR BUSINESS, OPERATING RESULTS OR
FINANCIAL CONDITION COULD BE MATERIALLY ADVERSELY AFFECTED BY THESE RISKS. THE
TRADING PRICE OF OUR COMMON STOCK COULD DECLINE DUE TO ANY OF THESE RISKS, AND
YOU MAY LOSE ALL OR PART OF YOUR INVESTMENT. YOU SHOULD ALSO REFER TO THE OTHER
INFORMATION INCLUDED IN THIS PROSPECTUS.
 
OUR SUBSTANTIAL LEVERAGE COULD ADVERSELY AFFECT OUR ABILITY TO RUN OUR BUSINESS
 
    We have now and will continue to have a significant amount of indebtedness.
As of March 31, 1999, we had $1.3 billion of indebtedness and a stockholders
deficit of $123.6 million (as adjusted for the conversion of certain securities
into common stock). Furthermore, our senior discount notes will accrete in value
(i.e., effectively increase in principal amount) by $241.8 million before they
begin to pay interest in cash. Our substantial indebtedness could have important
consequences to you. For example, it could:
 
    - limit our ability to obtain additional financing for working capital,
      capital expenditures, acquisitions and general corporate purposes;
 
    - require us to dedicate a substantial portion of our cash flow from
      operations to payments on our indebtedness, thereby reducing the funds
      available to us for other purposes, including working capital, capital
      expenditures, acquisitions and general corporate purposes;
 
    - make us more vulnerable to economic downturns, limiting our ability to
      withstand competitive pressures and reduce our flexibility in responding
      to changing business and economic conditions;
 
    - limit our flexibility in planning for, or reacting to, changes in our
      business and the industry in which we operate;
 
    - place us at a competitive disadvantage compared to our competitors that
      have less debt; and
 
    - limit, along with the financial and other restrictive covenants, our
      ability to borrow additional funds.
 
    Any of the foregoing could have a material adverse effect on the price of
our common stock.
 
TO DATE, WE HAVE INCURRED SUBSTANTIAL NET LOSSES AND NEGATIVE CASH FLOW FROM
OPERATIONS, AND IF THIS CONTINUES, WE WILL BE UNABLE TO MEET OUR WORKING CAPITAL
AND FUTURE DEBT SERVICE REQUIREMENTS
 
    Our operating loss, negative EBITDA and net loss have increased for each of
the last four years. In 1998, we had an operating loss of $48.1 million,
negative EBITDA of $31.8 million and a net loss of $127.3 million. We also had
interest expense of $79.2 million and capitalized interest of $3.3 million.
Interest expense will increase substantially as a result of the offering which
we completed in March 1999. These losses and our high interest expense present a
significant risk for investors. We need to increase traffic on our network to
reduce our per minute costs and reverse these trends.
 
    Our negative EBITDA and negative cash flow are likely to continue beyond the
year 2000 if:
 
    - we extend our expansion plans,
 
    - prices charged to end users decline faster than we anticipate,
 
    - interconnection rates and wholesale prices paid by us do not decline as
      quickly as we anticipate, or
 
    - any of the other risks described in this prospectus materialize.
 
Accordingly, we cannot assure you that we will achieve or sustain profitability
or positive cash flows from operating activities in the future. If we cannot
achieve profitability or positive cash flows from operating activities, we may
be unable to meet our working capital and future debt service requirements which
would
 
                                       9
<PAGE>
have a material adverse effect on our business, financial condition, results of
operations and the price of our common stock.
 
OUR CASH FLOW MAY NOT BE SUFFICIENT TO PERMIT REPAYMENT OF OUR INDEBTEDNESS WHEN
  DUE
 
    Our ability to make payments on and to refinance our indebtedness will
depend on our ability to generate cash in the future. We cannot assure you that
our business will generate sufficient cash flow from operations to meet our debt
service requirements. We may need to refinance all or a portion of our
indebtedness. Based on our current level of operation, we anticipate that cash
flow from operations may be insufficient to repay our indebtedness at scheduled
maturity and that some or all of such indebtedness may need to be refinanced. If
we are unable to refinance our debt or if additional financing is not available,
we could be forced to dispose of assets under circumstances that might not be
favorable to realizing the highest price for the assets or to default on our
obligations with respect to our indebtedness, either of which could have a
material adverse effect on the price of our common stock.
 
DUE TO RESTRICTIONS IN OUR INDENTURES, WE MAY NOT BE ABLE TO OPERATE OUR
  BUSINESS AS WE DESIRE
 
    The indentures under which our long-term debt was issued contain a number of
conditions and/or limitations on the way in which we can operate our business.
These limitations may force us to pursue less than optimal business strategies
or forego business arrangements which could have been financially advantageous
to us and our stockholders. The indentures restrict, and in some cases
significantly limit or prohibit, among other things, our ability and the ability
of our subsidiaries to:
 
    - incur additional indebtedness,
 
    - make prepayments of certain indebtedness,
 
    - pay dividends,
 
    - make investments,
 
    - engage in transactions with stockholders and affiliates,
 
    - issue capital stock,
 
    - create liens,
 
    - sell assets, and
 
    - engage in mergers and consolidations.
 
    Any of these limitations could have a material adverse effect on the price
of our common stock.
 
OUR FUTURE GROWTH WILL REQUIRE SUBSTANTIAL ADDITIONAL CAPITAL WHICH COULD EXCEED
BUDGETED AMOUNTS AND CAUSE US TO DELAY OR ABANDON EXPANSION PROJECTS
 
    Our future growth will require substantial additional capital which may
exceed budgeted amounts. If we do not have sufficient cash to fund our growth as
planned, we may be required to delay or abandon some or all of our development
and expansion plans or we may have to seek additional money earlier than we
currently anticipate. We cannot assure you that additional financing
arrangements will be available to us on acceptable terms or at all. Moreover,
the amount of our outstanding indebtedness may adversely affect our ability to
raise additional financing. Our inability to obtain additional financing when
required on acceptable terms could have a material adverse effect on the price
of our common stock.
 
                                       10
<PAGE>
FAILURE TO IMPLEMENT OUR STRATEGY OF OWNING FACILITIES COULD SIGNIFICANTLY
IMPACT OUR FINANCIAL PERFORMANCE
 
    If we are unable to successfully implement our strategy of owning, rather
than leasing, telecommunications facilities, we could experience a significant
decrease in the margin which we make on long distance calls. This decrease,
absent a significant increase in the number of billable minutes which we carry
or the amount we can charge for additional services, would have a material
adverse effect on our business, financial condition, results of operations and
on the price of our common stock.
 
WE MAY NOT BE ABLE TO PROVIDE DATA TRANSMISSION SERVICES EFFECTIVELY
 
    We have no direct experience in providing data transmission services and,
consequently, we can provide no assurance that we will be successful in the data
transmission business. Our ability to successfully enter the data transmission
business will depend upon, among other things:
 
    - our ability to select new equipment and software and integrate these into
      our network,
 
    - hire and train qualified personnel, and
 
    - enhance our billing, back-office and information systems to accommodate
      data transmission services and customer acceptance of our service
      offerings.
 
If we are not successful, there may be a material adverse effect on our
business, financial condition, results of operations and the price of our common
stock.
 
    The data transmission business is extremely competitive and prices have
declined substantially in recent years and are expected to continue to decline.
In providing these services, we will be dependent upon vendors for assistance in
the planning and deployment of our data product offerings, as well as ongoing
training and support. Our provider for asynchronous transfer mode equipment is
Lucent. We believe that Lucent does not have extensive experience providing this
equipment, or configuring data networks, in Europe. In addition, this Lucent
equipment will need to be integrated with our existing Nortel Telecom-based
platforms. In Europe, there are a number of different protocols for data
transmission. Our network will need to be able to handle all of these protocols,
which will pose technical difficulties.
 
    The asynchronous transfer mode network equipment we are installing is
designed to enable us to carry voice calls using Internet Protocol as well as
using traditional circuit switched technology. While we do not anticipate a
wholesale conversion to voice over Internet Protocol in the near future, we may
use this protocol to carry some portion of our voice traffic. Traditionally,
voice calls have been transmitted by keeping a circuit or line open between the
calling parties for the duration of the call. This method to transmit voice
calls is inefficient because during conversations there are pauses and periods
of silence when the capacity of the circuit is not being used. Voice
communications carried over data transmission technologies are designed to
eliminate this inefficiency. This technology breaks the voice conversation into
"packets" of information and sends those packets over transmission lines
individually. The packets are then re-assembled at or near their destination, so
the parties are able to have a conversation. When the parties on the call pause
or are silent, there are no packets transmitted and the transmission lines can
be used for other purposes. This technology promises to substantially improve
the efficiency of carrying voice conversations, reducing their cost.
 
    Some telecommunications companies (including ICG Communications, Inc., IDT
Corporation and RSL Communications Ltd.) are carrying calls over similar
technologies today and many others are developing this technology (including
Sprint Corporation). However, carrying voice communications over Internet
Protocol is still under development, is extremely complex and has not, in our
judgement, been developed to quality levels equal to those of traditional voice
transmission methods. We do not currently carry voice communications over
Internet Protocol on our network. Accordingly, there is a risk that we will not
be able to develop this technology well enough to be able to use it for voice
traffic and, therefore, will
 
                                       11
<PAGE>
not be able to enjoy the cost reductions it promises. Furthermore, it is not
clear today which of the emerging versions of this technology will prevail. We
believe the asynchronous transfer mode technology we are implementing is
adaptable to future developments of voice over Internet Protocol technology.
Many telecommunications companies have far more experience with these types of
issues than we do. Our failure to successfully carry voice communications using
data transmission technologies could have a material adverse effect on the price
of our common stock.
 
OUR OPERATING RESULTS MAY BE SUBJECT TO SUBSTANTIAL FLUCTUATIONS
 
    Any significant shortfall in demand for our services in relation to
expectations, or the occurrence of any other factors which cause revenue to fall
significantly short of expectations, would have a material adverse effect on our
business, financial condition, results of operations and the price of our common
stock. Additional factors which may cause our operating results to fluctuate in
the future include:
 
    - pricing changes in the industry;
 
    - changes in the mix of services which we sell or channels through which
      those services are sold;
 
    - timing and amount of capacity sales;
 
    - changes in user demand, customer terminations of service, capital
      expenditures and other costs relating to the expansion of our network;
 
    - the start-up and ready-for service dates of each phase of our network
      expansion;
 
    - the timing and costs of any acquisitions of customer bases, businesses,
      services or technologies;
 
    - the timing and costs of marketing and advertising efforts;
 
    - the effects of government regulation and regulatory changes; and
 
    - specific economic conditions in the telecommunications industry.
 
OUR ABILITY TO USE NET OPERATING LOSS CARRYFORWARDS MAY BE LIMITED IN THE FUTURE
 
    As of December 31, 1998, we had federal income tax net operating loss
carryforwards of $218.8 million which begin to expire in 2007. A tax asset
related to this loss carryforward does not appear on our balance sheet because
it is unclear if we will generate taxable income prior to the expiration of the
net operating loss carryforwards. Our ability to use net operating loss
carryforwards, to reduce our future tax payments would be limited if there were
to occur a more than fifty percent ownership change over a three-year period. As
a result of an ownership change in October 1996, certain of our net operating
loss carryforwards from before such time are subject to this limitation. It is
possible that this offering, when combined with prior or subsequent direct or
indirect changes in the ownership of our common stock within the relevant
three-year period, could trigger this limitation.
 
OUR INDUSTRY IS HIGHLY COMPETITIVE WITH PARTICIPANTS THAT HAVE GREATER RESOURCES
THAN WE DO, AND WE MAY NOT BE ABLE TO COMPETE SUCCESSFULLY
 
    Our success depends upon our ability to compete with other
telecommunications providers in each of our markets, many of which have
substantially greater financial, marketing and other resources than we do. If
our competitors devote significant additional resources to the provision of
international or national long distance telecommunications services to our
target customer base, this action could have a material adverse effect on our
business, financial condition, results of operations and the price of our common
stock. We cannot assure you that we will be able to compete successfully.
 
    Our competitors include the incumbent telecommunications operator in each
country in which we operate, global alliances among some of the world's largest
telecommunications carriers, such as British
 
                                       12
<PAGE>
Telecom and AT&T, Global One (Sprint, France Telecom and Deutsche Telekom) and
the alliance between MCI Worldcom and Telefonica de Espana, and new entrants,
such as alternative carriers, Internet backbone networks and other service
providers. In addition, Colt Telecom Group and Level 3 Communications are
sharing the costs of constructing two networks -- one to link the German cities
of Berlin, Koln, Dusseldorf, Frankfurt, Hamburg, Munich and Stuttgart and the
other linking Paris, Frankfurt, Amsterdam, Brussels and London. Other potential
competitors include:
 
    - cable communications companies,
 
    - wireless telephone companies,
 
    - electric and other utilities with rights-of-way,
 
    - railways,
 
    - microwave carriers and
 
    - large end-users which have private networks.
 
The intensity of competition and price declines in both billable minutes and
capacity have increased over the past several years and we believe that
competition and price declines will continue to intensify, particularly in
Western Europe, as other providers obtain operative connectivity.
 
    We are aware that certain long distance carriers are expanding their
capacity and believe that other long distance carriers and data service
providers, as well as potential new entrants to the industry, are considering
the construction of new fiber optic and other long distance transmission
networks. Since the cost of the actual fiber is a relatively small portion of
building new transmission lines, persons building such lines are likely to
install fiber that provides substantially more transmission capacity than will
be needed over the short or medium term. Further, recent technological advances
have shown the potential to greatly expand the capacity of existing and new
fiber optic cable. In addition, our sales or leases of capacity on the Circe
Network to other carriers may result in competitors having capacity on our
routes along the Circe Network, which may in turn result in pricing pressures
with respect to traffic carried along these routes. If industry capacity
expansion results in capacity that exceeds overall demand in general or along
any of our routes, severe additional pricing pressure could develop. In
addition, strategic alliances or similar transactions could result in additional
pricing pressure on long distance carriers. Such pricing pressure could have a
material adverse effect on us and the value of our common stock. See
"Management's Discussion and Analysis of Financial Condition and Results of
Operations--Overview."
 
THE COSTS AND DIFFICULTIES OF ACQUIRING AND INTEGRATING BUSINESSES COULD IMPEDE
OUR FUTURE GROWTH AND ADVERSELY AFFECT OUR COMPETITIVENESS
 
    We may seek to acquire customer bases and businesses from, make investments
in, or enter into strategic alliances with, other companies, which may expose us
to the following risks:
 
    - the difficulty of identifying appropriate acquisition candidates in the
      countries in which we do business;
 
    - the difficulty of assimilating the operations and personnel of the
      acquired entities;
 
    - the potential disruption to our ongoing business caused by senior
      management's focus on the acquisition transactions;
 
    - our failure to successfully incorporate licensed or acquired technology
      into our network and service offerings;
 
    - the failure to maintain uniform standards, controls, procedures and
      policies; and
 
                                       13
<PAGE>
    - the impairment of relationships with employees as a result of changes in
      management and ownership.
 
    Additionally, in connection with an acquisition, we may experience rates of
customer attrition that are significantly higher than the rate of customer
attrition which we generally experience and will generally record goodwill that
must be amortized and which would reduce our earnings per share. Further, to the
extent that any transaction involves customer bases or businesses located
outside the United States, the transaction would involve the risks associated
with international operations. We cannot assure you that we would be successful
in overcoming these risks and our failure to overcome these risks could have a
material adverse effect on our business, financial condition, results of
operations and the price of our common stock.
 
NETWORK CONSTRUCTION DELAYS AND SYSTEM DISRUPTIONS OR FAILURES COULD ADVERSELY
  AFFECT OUR BUSINESS
 
    Our success is dependent, in part, on our ability to continue to expand our
network and on our ability to provide seamless technical operation of the
network. Furthermore, as we continue to expand our network to increase its
capacity and reach, we will face increasing demands and challenges including:
 
    - effectively managing the construction of new fiber routes, obtaining any
      necessary rights-of-way and required licenses for such construction, and
      completing any such construction on budget and on time,
 
    - increasing traffic volume on our network, and
 
    - selling capacity on the network.
 
    If the costs of construction projects significantly exceed our budget for
those projects, we may be required to obtain additional financing or to abandon
or curtail portions of those projects. If we encounter construction delays, we
will not be able to route our traffic over our owned facilities as soon as we
hope, which will, for some period of time, have a detrimental effect on our
ability to increase traffic volumes and gross margins. In addition, construction
delays could negatively affect our ability to sell indefeasible rights-of-use or
capacity to other carriers. Our network is subject to several risks which are
outside of our control, such as:
 
    - the risk of damage to software and hardware resulting from fire,
 
    - power loss,
 
    - natural disasters, and
 
    - general transmission failures caused by a number of additional factors.
 
    Any failure of our network or other systems or hardware that causes
significant interruptions to our operations could have a material adverse effect
on our business, financial condition, results of operations and on the price of
our common stock.
 
    Our operations are also dependent on our ability to successfully integrate
new and emerging technologies and equipment into the network, which could
increase the risk of system failure and result in further strains upon our
network. We attempt to minimize customer inconvenience in the event of a system
disruption by routing traffic to other circuits and switches which may be owned
by other carriers. However, prolonged or significant system failures, or
difficulties for customers in accessing and maintaining connection with our
network, could seriously damage our reputation and result in customer attrition,
reduced margins and financial losses and, as a result, have a material adverse
effect on the price of our common stock. Additionally, any damage to our
switching centers in New York, New York, Somerset, New Jersey, London, England
or Egham, England could have a material adverse effect on our ability to manage
our network operations and generate accurate call detail reports and, in the
case of our switching centers in Somerset and Egham, to monitor the system.
 
                                       14
<PAGE>
    The expansion and development of our network will entail the significant
expenditure of resources in projecting growth in traffic volume and routing
preferences and determining the most cost effective means of growing the
network, for example, through variable or fixed lease arrangements, the purchase
of capacity or minimum investment units on digital fiber optic cables or digital
microwave equipment, or the further construction of transmission infrastructure.
Failure to project traffic volume and route preferences correctly or to
determine the optimal means of expanding our network would result in less than
optimal utilization of our network and could have a material adverse effect on
our business, financial condition, results of operations and on the price of our
common stock.
 
FOREIGN CURRENCY EXCHANGE RATES COULD HAVE ADVERSE EFFECTS ON OUR BUSINESS
 
    Our payment obligations with respect to our outstanding indebtedness are
denominated in U.S. Dollars and the Euro, but certain of our revenues are
denominated in Pound Sterling. Any appreciation in the value of the U.S. Dollar
or the Euro relative to the Pound Sterling could have a material adverse effect
on our ability to make payments on such obligations.
 
    In the future we may elect to manage exchange rate exposure presented by our
euro denominated obligations through the use of hedging transactions. We cannot
provide any assurance that exchange rate fluctuations will not have a material
adverse effect on our ability to make payments on our outstanding indebtedness.
 
    In addition, we cannot assure you that the laws or administrative practices
relating to taxation, foreign exchange or other matters in countries within
which we operate will not change. Any such change could have a material adverse
effect on our business, financial condition, results of operations and the price
of our common stock.
 
WE COULD EXPERIENCE SYSTEM FAILURES AND SERVICE DISRUPTIONS AS A RESULT OF THE
  YEAR 2000 ISSUE
 
    We face certain risks arising from Year 2000 issues which could have a
material adverse affect on our business, financial condition, results of
operations and the price of our common stock. See "Management's Discussion and
Analysis of Financial Condition and Results of Operations--Year 2000."
 
OUR DEPENDENCE UPON THIRD PARTIES FOR LEASED CAPACITY AND INTERCONNECTION
ARRANGEMENTS MAY RESULT IN SUBOPTIMAL UTILIZATION OF OUR NETWORK
 
    We currently lease capacity for point-to-point circuits with fixed monthly
payments and buy minutes of use under agreements with maximum twelve-month terms
and are vulnerable to changes in our lease arrangements, capacity limitations
and service cancellations. These lease arrangements present us with high fixed
costs, while revenues generated by the utilization of these leases will vary
based on traffic volume and pricing. Accordingly, if we are unable to generate
sufficient traffic volume over particular routes or are unable to charge
appropriate rates, we could fail to generate revenue sufficient to meet the
fixed costs associated with the lease and may incur negative gross margins with
respect to those routes. A deterioration of our relationship with one or more
carriers could have a material adverse effect on our cost structure, service
quality, network coverage, financial condition and results of operations.
 
    Our ability to access customers and to effectively utilize our network is
dependent upon our ability to secure operative interconnection agreements,
providing access to and an exit from the public switched telephone network, with
the respective incumbent telecommunications operator in each market in which we
operate. Difficulties or delays in obtaining necessary operative
interconnections in a satisfactory or timely manner may significantly delay or
prevent the maximum utilization of our network which could have a material
adverse effect on us and the price of our stock.
 
                                       15
<PAGE>
LOSS OF SIGNIFICANT CARRIER CUSTOMERS WOULD RESULT IN A SIGNIFICANT LOSS OF
  REVENUES
 
    We currently derive a significant portion of our revenues from a relatively
small number of carrier customers. During the three months ended March 31, 1999
and the year ended December 31, 1998, carrier customers accounted for 34.2% and
58.3% of our total revenue, respectively, with one carrier customer accounting
for 10.6% of total revenue for the year ended December 31, 1998. Accordingly,
the loss of revenue from more than one significant carrier customer would have a
material adverse effect upon our business, financial condition, results of
operations and the price of our common stock.
 
OUR BUSINESS WILL SUFFER IF WE LOSE CERTAIN KEY PERSONNEL OR FAIL TO ATTRACT AND
RETAIN OTHER QUALIFIED PERSONNEL
 
    The success of our business is dependent, to a significant extent, upon the
abilities and continued efforts of our senior management, and particularly upon
the abilities and efforts of Michael J. Mahoney, our Chairman, Chief Executive
Officer and President. We do not currently have employment agreements with any
employee other than Mr. Mahoney, Allan L. Shaw, our Senior Vice President of
Finance and Chief Financial Officer and Sheldon M. Goldman, our Senior Vice
President, Business Affairs and General Counsel nor do we intend to enter into
any employment agreements with any employee other than Lawrence G. Malone, our
Senior Vice President, Global Sales and Marketing and Francis J. Mount, our
Senior Vice President, Engineering and Network Operations. See
"Management--Employment Agreements." Except for a $3.0 million key-man life
insurance policy on the life of Mr. Mahoney, we do not maintain and do not
contemplate obtaining such life insurance policies on any of our employees.
 
    The success of our business also depends on our ability to attract, retain
and motivate qualified management, marketing, technical and sales executives and
other personnel who are in high demand and who often have multiple employment
options. In addition, the labor market for software engineers and central office
technicians has been extremely competitive recently and we may lose key
employees or be forced to increase their compensation. The loss of the services
of key personnel, or the inability to attract additional qualified personnel,
could have a material adverse effect on our business, financial condition,
results of operations and the price of our common stock. We cannot assure you
that we will be successful in attracting, retaining and motivating personnel.
 
CERTAIN PROVISIONS OF OUR CORPORATE DOCUMENTS AND OUR EMPLOYMENT CONTRACTS MAY
MAKE A TAKEOVER MORE DIFFICULT EVEN IF THE TAKEOVER WOULD BENEFIT STOCKHOLDERS
 
    Our certificate of incorporation and by-laws include certain provisions that
are intended to enhance the likelihood of continuity and stability in the
composition of our board of directors. These provisions may render the removal
of directors and management more difficult. In addition, our certificate of
incorporation authorizes the issuance of "blank check" preferred stock. These
provisions may have the effect of delaying, deterring or preventing a future
takeover or change in control of Viatel, unless such takeover or change in
control is approved by our board of directors, even though such a transaction
might offer holders of our common stock an opportunity to sell their shares at a
price above the current market price.
 
    Section 203 of the Delaware General Corporation Law (the "DGCL") also
imposes certain restrictions on mergers and other business combinations between
us and any holder of 15% or more of our common stock.
 
    In addition, the employment agreements between Viatel and each of Messrs.
Mahoney, Shaw and Goldman contain, and the employment agreements to be executed
by each of Messrs. Malone and Mount will contain, provisions which require us to
make certain payments to those officers in certain instances if employment is
terminated following certain specified events.
 
                                       16
<PAGE>
    Certain provisions of the DGCL and some of our employment agreements may
delay, deter or prevent someone from acquiring us in a transaction that results
in stockholders receiving a premium over the market price for the shares of
common stock. See "Management--Employment Agreements" and "Description of
Capital Stock--Certificate of Incorporation and By-laws." Such requirements may
delay, prevent or deter a change in control of our company.
 
    In addition to the foregoing, under our indentures, in the event of a change
of control we must offer to purchase all our outstanding indebtedness at a
purchase price equal to 101% of the principal amount or the accreted value of
such notes. This requirement may deter third parties from entering into a merger
transaction with us and may have an adverse effect on the price of our common
stock.
 
WE ARE SUBJECT TO SUBSTANTIAL GOVERNMENT REGULATION WHICH MAY AFFECT OUR ABILITY
TO OFFER CERTAIN SERVICES AND WHICH MAY BE CHANGED IN A MANNER ADVERSE TO VIATEL
 
    OVERVIEW.  National and local laws and regulations governing the provision
of telecommunications services differ significantly among the countries in which
we currently operate and intend to operate. The interpretation and enforcement
of such laws and regulations varies and could limit our ability to provide
certain communications services in certain markets. We cannot assure you that:
 
    - future regulatory, judicial and legislative changes will not have a
      material adverse effect on us;
 
    - domestic or international regulators or third parties will not raise
      material issues with regard to our compliance with applicable laws and
      regulations; or
 
    - other regulatory activities will not have a material adverse effect on our
      business, financial condition and results of operations.
 
    INTERNATIONAL TRAFFIC.  Under the World Trade Organization Basic Telecom
Agreement, concluded on February 15, 1997, 69 countries comprising 95% of the
global market for basic telecommunications services agreed to permit competition
from foreign carriers. In addition, 59 of these countries have subscribed to
specific procompetitive regulatory principles. The WTO Agreement became
effective on February 5, 1998 and has been implemented, to varying degrees, by
the signatory countries.
 
    On November 26, 1997, the FCC adopted the Foreign Participation Order to
implement the U.S. obligations under the WTO Agreement. In this order, the FCC
adopted an open entry standard for carriers from World Trade Organization member
countries, generally facilitating market entry for such applicants by
eliminating certain existing tests. These tests remain in effect, however, for
carriers from non-World Trade Organization member countries.
 
    International carriers serving the United States, including us, are subject
to the FCC's international settlements policy. The international accounting rate
system allows a U.S. facilities-based carrier to negotiate an accounting rate
with a foreign carrier for handling each minute of international telephone
service. Each carrier's portion of the accounting rate, usually one-half, is
referred to as the settlement rate. Historically, international settlement rates
have vastly exceeded the cost of terminating telecommunications traffic. The
FCC's international settlements policy requires: (1) the equal division of the
accounting rate between the U.S. and foreign carrier; (2) nondiscriminatory
treatment of U.S. carriers, and (3) proportionate return of inbound traffic. To
enforce the international settlements policy, the FCC has required carriers to
file publicly available copies of their international settlement arrangements.
 
    The FCC adopted rules regarding specific rate levels for international
settlements which became effective on January 1, 1998. The International
Settlement Rates Order generally requires U.S. facilities-based carriers to
negotiate settlement rates with their foreign correspondent at no greater than
FCC-established benchmark prices. In addition, the International Settlement
Rates Order imposed new conditions upon certain carriers, including us. First,
the FCC conditioned facilities-based authorizations for service on a route on
which a carrier has a foreign affiliate upon the foreign affiliate offering all
other
 
                                       17
<PAGE>
U.S. carriers a settlement rate at or below the relevant benchmark. Our foreign
affiliates satisfy this condition. Second, the FCC conditioned any authorization
to provide switched services over either facilities-based or resold
international private lines upon the condition that at least half of the
facilities based international message telephone service traffic on the subject
route is settled at or below the relevant benchmark rate. This condition applies
whether or not the licensee has a foreign affiliate on the route in question.
 
    In the Foreign Participation Order described above, if the subject route
does not comply with the benchmark requirement, a carrier can demonstrate that
the foreign country provides equivalent resale opportunities. Accordingly, since
the February 9, 1998 effective date of the Foreign Participation Order, we have
been permitted to resell private lines for the provision of switched services,
also known as international simple resale, to any country that either has been
found by the FCC to comply with the benchmarks or has been determined to be
equivalent. We, however, remain subject to prior FCC approval in order to
provide resold private lines to any country in which we have an affiliated
carrier that has not been found by the FCC to lack market power.
 
    Many parties appealed the International Settlement Rates Order to the U.S.
Court of Appeals for the D.C. Circuit or have filed requests for reconsideration
with the FCC. On January 12, 1999, the U.S. Court of Appeals for the D.C.
Circuit issued an order resolving this appeal, upholding the International
Settlement Rates Order in all respects. The appealing parties now have until
June 9, 1999 to exercise the option of requesting that the case be heard by the
U.S. Supreme Court. The petition for reconsideration is still pending at the
FCC. We cannot predict the outcome of these proceedings and their possible
impact on us or the price of the common stock.
 
    In new rules released on May 6, 1999, but not yet effective, the FCC has
removed the international settlements policy for: (1) all settlement
arrangements between U.S. carriers and foreign carriers that lack market power;
and (2) all settlement arrangements on routes where U.S. carriers are able to
terminate at least 50 percent of their traffic in the foreign market at rates
that are at least 25 percent below the applicable benchmark settlement rate. In
this international settlements policy order, the FCC also eliminated the
requirement that carriers file the settlement arrangements where the
international settlement policy has been eliminated. Finally, the international
settlements policy order expanded its rules to permit carriers to provide
international simple resale on any route where the resale carrier exchanges
switched traffic with a foreign carrier that lacks market power. Accordingly,
upon the effectiveness of these new rules, we will have more flexibility in
negotiating settlement arrangements with many carriers on many routes, which we
expect will lower our costs of terminating international traffic, although our
competitors will benefit from these new rules in the same way.
 
    Increasing regulatory liberalization in many countries' telecommunications
markets now permits more flexibility in the way we can route calls. Certain FCC
rules limit the way in which some international calls can be routed.
Accordingly, it is possible that the FCC could find that our network
configuration violates these rules. If we were found to be in violation of these
routing restrictions, and if the violation was sufficiently severe, it is
possible that the FCC could impose sanctions and penalties upon us.
 
    CALL REORGINATION.  In addition, outside the European Union we provide a
small number of customers with access to services through the use of call
reorigination. A substantial number of countries have prohibited certain forms
of call reorigination. We cannot assure you that certain of our services and
transmission methods will not be or not become prohibited in certain
jurisdictions and, depending on the jurisdictions, services and transmission
methods affected, there could be a material adverse effect on our business,
financial condition and results of operations.
 
    UNSETTLED NATURE OF REGULATORY ENVIRONMENT.  We have pursued and expect to
continue to pursue a strategy of providing our services to the maximum extent we
believe permissible under applicable laws and regulations. Our provision of
services in Western Europe may also be affected if any European Union member
state imposes greater restrictions on non-European Union international service
than on such
 
                                       18
<PAGE>
service within the European Union. We cannot assure you that the United States
or foreign jurisdictions will not adopt laws or regulatory requirements that
will adversely affect us.
 
    Additionally, we cannot assure you that future United States or foreign
regulatory, judicial or legislative changes will not have a material adverse
effect on us or that regulators or third parties will not raise material issues
with regard to our compliance with applicable laws or regulations. If we are
unable to provide the services we are presently providing or intend to provide
or to use our existing or contemplated transmission methods, due to:
 
    - our inability to receive or retain formal or informal approvals for such
      services or transmission methods, or
 
    - for any other reason related to regulatory compliance or the lack of such
      compliance, such events could have a material adverse effect on our
      business, financial condition and results of operations.
 
    Since January 1, 1998, we, as well as our U.S. competitors, have been
required by the FCC to make contributions to a universal service fund to
subsidize telecommunications services for low-income persons, schools and
libraries, and rural health care providers. These contributions are based upon
our gross revenues. There can be no assurance that we will be able fully to pass
the cost of these contributions on to our customers or that doing so will not
result in a loss of customers.
 
    EUROPEAN IMPLEMENTATION.  The national governments of the European Union
member states were required to pass legislation to liberalize the
telecommunications markets within their countries to implement European
Commission directives. Most of the member states have now implemented the
required legislation. In certain cases this has been done on an inconsistent,
and sometimes unclear, basis.
 
    In addition, the legislation and/or its implementation have, in certain
circumstances, imposed significant obstacles on the ability of carriers to
proceed with the necessary licensing process. Such barriers include:
 
    - requirements that carriers post significant bonds, make significant
      capital commitments to build infrastructure,
 
    - complete extensive application documentation,
 
    - and pay significant license fees.
 
    Implementation has also been slow in certain member states as a result of
such member state's failure to dedicate the resources necessary to have a
functioning regulatory body in place. The above factors and other obstacles
which could develop in connection with deregulation of telecommunications
services could have a material adverse effect on our operations by slowing down
the rate of our intended expansion, as well as a material adverse effect on our
business, financial condition, results of operations and the price of our common
stock.
 
THE MARKET PRICE OF OUR COMMON STOCK IS VOLATILE
 
    The market price of our common stock has been and can be expected to be
significantly affected by factors such as:
 
    - Quarterly variations in our results of operations;
 
    - The announcement of new services or service enhancements by us or our
      competitors;
 
    - Technological innovations by us or our competitors;
 
    - Changes in earnings estimates or buy/sell recommendations by analysts;
 
    - The operating and stock price performance of other comparable companies;
      and
 
                                       19
<PAGE>
    - General market conditions or market conditions specific to particular
      industries.
 
In particular, the stock prices for many companies in the telecommunications
sector have experienced wide fluctuations which have often been unrelated to the
operating performance of such companies. We have been, and are likely to
continue to be, subject to such fluctuations.
 
               SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS
 
    This prospectus contains forward-looking statements that involve substantial
risks and uncertainties. You can identify these statements by forward-looking
words such as "anticipate," "believe," "could," "estimate," "expect," "intend,"
"may," "should," "will" and "would" or similar words. You should read statements
that contain these words carefully because they discuss our future expectations,
contain projections of our future results of operations or of our financial
position or state other "forward-looking" information. We believe that it is
important to communicate our future expectations to our investors. However,
there may be events in the future that we are not able to accurately predict or
control. The factors listed above in the section captioned "Risk Factors," as
well as any cautionary language in this prospectus, provide examples of risks,
uncertainties and events that may cause our actual results to differ materially
from the expectations we describe in our forward-looking statements. Before you
invest in our common stock, you should be aware that the occurrence of the
events described in these risk factors and elsewhere in this prospectus could
have a material adverse effect on our business, results of operations, financial
position and the price of our common stock.
 
                                       20
<PAGE>
                                USE OF PROCEEDS
 
    The net proceeds from this offering are estimated to be approximately $196.3
million assuming an offer price of $52.13 per share (approximately $222.5
million if the over-allotment option is exercised in full), after deducting
underwriting discounts and commissions and offering expenses payable by us. We
intend to use the net proceeds from this offering principally to fund the
further development of the Circe Network as well as for working capital and
general corporate purposes. Pending utilization of the net proceeds, we intend
to invest such proceeds in short-term, interest-bearing, high quality
securities.
 
    We believe that the net proceeds from this offering, together with cash and
marketable securities on hand and the proceeds from the sale of capacity on the
Circe Network will provide sufficient funds for us to expand our business as
planned and to fund losses for at least the next 12 to 18 months. However, the
amount of our future capital requirements and losses will depend on a number of
factors, including the success of our business, the start-up dates of the
unfinished rings of the Circe Network, the rate at which we further expand our
network, the types of services that we offer, staffing levels, acquisitions and
customer growth, as well as other factors that are not within our control,
including competitive conditions, government regulatory developments and capital
costs. In the event that our plans or assumptions change or prove to be
inaccurate, or the net proceeds of this offering and the sale of capacity on the
Circe Network prove to be insufficient to fund our capital expenditures and
losses in the manner and at the rate currently anticipated, we may be required
to delay or abandon some or all of our development and expansion plans or we may
be required to seek additional sources of financing earlier than currently
anticipated. See "Risk Factors--Our Cash Flow May Not Be Sufficient to Permit
Repayment of Our Indebtedness."
 
    We will not receive any of the proceeds from the sale of shares of our
common stock by the selling stockholders.
 
                                    DILUTION
 
    Our net tangible book value at March 31, 1999, as adjusted for the
conversion of our Series A preferred stock and subordinated convertible
debentures, was $(194.2) million, or $(6.98) per share of our common stock. Our
as adjusted net tangible book value per share represents the amount of our total
tangible assets less our total liabilities, divided by the number of shares of
common stock outstanding. After giving effect to the receipt of the net proceeds
from the sale of the 4,000,000 shares of our common stock offered by us hereby,
at an estimated offering price of $52.13 per share, after deducting underwriting
discounts and commissions and estimated offering expenses, our pro forma as
adjusted net tangible book value at March 31, 1999, would have been $2.1
million, or $0.7 share. This represents an immediate increase in net tangible
book value of $7.05 per share to existing stockholders and an immediate dilution
of $52.06 per share to the new investors purchasing our common stock at the
public offering price. The following illustrates this per share dilution:
 
<TABLE>
<S>                                                                   <C>        <C>
Estimated public offering price per share...........................             $   52.13
As adjusted net tangible book value per share as of March 31, 1999
  before this offering..............................................  $   (6.98)
Increase per share attributable to new investors....................       7.05
                                                                      ---------
Pro forma, as adjusted net tangible book value per share at March
  31, 1999 after this offering......................................                   .07
                                                                                 ---------
Dilution per share to new investors.................................             $   52.06
                                                                                 ---------
                                                                                 ---------
</TABLE>
 
    The foregoing table does not include (i) shares of common stock to be issued
upon exercise of the underwriters' over-allotment option and (ii) outstanding
options at May 17, 1999 to purchase a total of approximately 3.1 million shares
of common stock at prices ranging from $.75 to $22.88, with a weighted
 
                                       21
<PAGE>
average exercise price of $10.28 per share, and an additional 1.0 million shares
reserved for future grants under Viatel's stock incentive plan.
 
                          PRICE RANGE OF COMMON STOCK
 
    Our common stock is quoted on the Nasdaq Stock Market under the symbol
"VYTL." The following table sets forth, for each of the periods indicated, the
high and low sales prices per share of common stock as reported on the Nasdaq
National Market.
 
<TABLE>
<CAPTION>
                      HIGH        LOW
                     -------    -------
<S>                  <C>        <C>
1997
  First Quarter.....   9 1/2      6 5/8
  Second Quarter....   7          6
  Third Quarter.....   6 5/8      4 1/4
  Fourth Quarter....   7          5
 
1998
  First Quarter.....  13 3/4      5
  Second Quarter....  17          7
  Third Quarter.....  20 3/4      8 1/8
  Fourth Quarter....  23 1/2      7 1/4
1999
  First Quarter.....  28 5/8     17
  Second Quarter
  (through May 19,
  1999).............  52 7/8     28 1/8
</TABLE>
 
    On May 19, 1999, the reported last sale price of our common stock on the
Nasdaq National Market was $52 1/8 per share.
 
                                       22
<PAGE>
                                DIVIDEND POLICY
 
    We have not paid any dividends on our common stock and do not intend to pay
any dividends on our common stock in the foreseeable future. We currently intend
to retain our future earnings, if any, to finance the future growth of our
business. In addition, our ability to pay cash dividends is currently restricted
under the terms of the indentures related to our existing senior indebtedness.
Future dividends, if any, will be determined by our board of directors.
 
                                 CAPITALIZATION
 
    The following table sets forth the cash and cash equivalents, various other
assets and the capitalization of Viatel as of March 31, 1999 on an actual basis,
on an as adjusted basis to give effect to the conversion of our Series A
redeemable convertible preferred stock and subordinated convertible debentures,
and on a pro forma as adjusted basis to reflect the application of the net
proceeds from the sale of the 4,000,000 shares of common stock offered by us
hereby, at an estimated public offering price of $52.13 per share, after
deducting underwriting discounts and commissions and estimated offering
expenses. You should read the information in this table in conjunction with "Use
of Proceeds," "Selected Consolidated Financial Data," "Management's Discussion
and Analysis of Financial Condition and Results of Operations" and our financial
statements and related notes thereto included elsewhere in this prospectus.
 
<TABLE>
<CAPTION>
                                                                                         AS OF
                                                                                    MARCH 31, 1999
                                                                        ---------------------------------------
                                                                                    AS ADJUSTED     PRO FORMA
                                                                                        FOR        AS ADJUSTED
                                                                         ACTUAL     CONVERSION    FOR OFFERING
                                                                        ---------  -------------  -------------
                                                                           (IN THOUSANDS, EXCEPT SHARE DATA)
<S>                                                                     <C>        <C>            <C>
Cash and cash equivalents.............................................  $ 442,042   $   442,042    $   638,348
                                                                        ---------  -------------  -------------
                                                                        ---------  -------------  -------------
Restricted cash equivalents...........................................  $  23,530        23,530    $    23,530
                                                                        ---------  -------------  -------------
                                                                        ---------  -------------  -------------
Cash securing letters of credit on network construction...............    121,239       121,239        121,239
                                                                        ---------  -------------  -------------
                                                                        ---------  -------------  -------------
Marketable securities, current........................................  $  56,713        56,713    $    56,713
                                                                        ---------  -------------  -------------
                                                                        ---------  -------------  -------------
Restricted marketable securities, current and non-current.............  $ 206,266       206,266    $   206,266
                                                                        ---------  -------------  -------------
                                                                        ---------  -------------  -------------
Long-term liabilities, excluding current installments:
    Long-term debt....................................................  $1,256,196  $ 1,243,715    $ 1,243,715
    Notes payable and obligations under capital leases................     36,286        36,286         36,286
                                                                        ---------  -------------  -------------
      Total long-term debt............................................  1,292,482     1,280,001      1,280,001
                                                                        ---------  -------------  -------------
Series A Redeemable Convertible Preferred Stock, $.01 par value;
  718,042 shares authorized; 472,791 shares issued and outstanding
  actual, 0 shares issued and outstanding pro forma for the conversion
  and 0, pro forma, as adjusted for this offering.....................     48,298       --             --
                                                                        ---------  -------------  -------------
Stockholders' deficiency:
    Common stock, $.01 par value; 50,000,000 shares authorized;
      23,193,265 shares issued and outstanding, actual, 27,798,615
      shares issued and outstanding, pro forma for the conversion and
      31,798,615, shares issued and outstanding pro forma as adjusted
      for this offering...............................................        232           278            318
    Additional paid-in capital........................................    128,403       188,673        384,939
    Accumulated other comprehensive loss..............................    (15,082)      (15,082)       (15,082)
    Accumulated deficit...............................................   (297,923)     (297,923)      (297,923)
                                                                        ---------  -------------  -------------
      Total stockholders' (deficiency) equity.........................   (184,370)     (124,054)        72,252
                                                                        ---------  -------------  -------------
        Total capitalization..........................................  $1,156,410  $ 1,155,947    $ 1,352,253
                                                                        ---------  -------------  -------------
                                                                        ---------  -------------  -------------
</TABLE>
 
    The total shares to be outstanding after this offering do not include (i)
shares of common stock to be issued upon exercise of the underwriters'
over-allotment option and (ii) outstanding options at May 17, 1999 to purchase a
total of approximately 3.1 million shares of common stock at prices ranging from
$.75 to $22.88, with a weighted average exercise price of $10.28 per share, and
an additional 1.0 million shares reserved for future grants under our stock
incentive plan.
 
                                       23
<PAGE>
                      SELECTED CONSOLIDATED FINANCIAL DATA
 
    The following selected consolidated financial data should be read in
conjunction with "Management's Discussion and Analysis of Financial Condition
and Results of Operations," our consolidated financial statements, including the
notes thereto, and the other financial data included elsewhere in this
prospectus. The statement of operations data, other financial data and balance
sheet data as of and for the years ended December 31, 1994, 1995, 1996, 1997 and
1998 are derived from the consolidated financial statements of Viatel and the
notes related thereto, which were audited by KPMG LLP, independent certified
public accountants. The consolidated financial statements as of December 31,
1997 and 1998 and for each of the years in the three-year period ended December
31, 1998 and the report of KPMG LLP thereon, are included elsewhere in this
prospectus. The selected consolidated statement of operations data, other
financial data and balance sheet data as of and for the three-month periods
ended March 31, 1998 and 1999 are derived from the unaudited consolidated
financial statements of Viatel included elsewhere in this prospectus, which, in
the opinion of management, include all adjustments necessary for a fair
presentation of the financial condition and results of operations of Viatel for
such periods. The results of operations for interim periods are not necessarily
indicative of a full year's operations. Net loss per share is computed on the
basis described in the notes to our consolidated financial statements. EBITDA
consists of earnings before interest, income taxes, extraordinary loss,
dividends on preferred stock and depreciation and amortization. Capital
additions for each period consist of capital expenditures, the net increase in
payables for property and equipment, assets acquired under capital lease
obligations and capitalized interest during the period. Restricted securities
represents government obligations purchased by us which secure the payment of
certain interest payments on its outstanding senior notes.
<TABLE>
<CAPTION>
                                                                                                        THREE MONTHS ENDED
                                                               YEAR ENDED DECEMBER 31,                      MARCH 31,
                                                -----------------------------------------------------  --------------------
<S>                                             <C>        <C>        <C>        <C>        <C>        <C>        <C>
                                                  1994       1995       1996       1997       1998       1998       1999
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
 
<CAPTION>
                                                                   (IN THOUSANDS, EXCEPT OPERATING DATA)
<S>                                             <C>        <C>        <C>        <C>        <C>        <C>        <C>
CONSOLIDATED STATEMENT OF OPERATIONS DATA:
Revenue:
  Communication services revenue..............  $  26,268  $  32,313  $  50,419  $  73,018  $ 131,938  $  21,239  $  48,395
  Capacity sales..............................     --         --         --         --          3,250     --         13,246
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
    Total revenue.............................     26,268     32,313     50,419     73,018    135,188     21,239     61,641
Operating expenses:
  Cost of services and sales..................     22,953     27,648     42,130     63,504    122,109     19,105     51,048
  Selling, general and administrative.........     14,463     24,370     32,866     36,077     44,893      8,955     18,763
  Depreciation and amortization...............        789      2,637      4,802      7,717     16,268      2,911      9,603
  Equipment impairment loss...................     --            560     --         --         --         --         --
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
    Total operating expenses..................     38,205     55,215     79,798    107,298    183,270     30,971     79,414
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
Operating loss................................    (11,937)   (22,902)   (29,379)   (34,280)   (48,082)    (9,732)   (17,773)
Interest income...............................        214      3,282      1,852      3,686     28,259        510      6,828
Interest expense..............................       (772)    (8,856)   (10,848)   (12,450)   (79,177)    (3,781)   (26,166)
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
Loss before extraordinary loss................    (12,495)   (28,476)   (38,375)   (43,044)   (99,000)   (13,003)   (37,111)
  Extraordinary loss on debt prepayment.......     --         --         --         --        (28,304)    --         --
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
Net loss......................................    (12,495)   (28,476)   (38,375)   (43,044)  (127,304)   (13,003)   (37,111)
Dividends on redeemable convertible preferred
  stock.......................................     --         --         --         --         (3,301)    --         (1,177)
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
Net loss attributable to common
  stockholders................................  $ (12,495) $ (28,476) $ (38,375) $ (43,044) $(130,605) $ (13,003) $ (38,288)
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
Loss per common share, basic and diluted:
  Before extraordinary item...................  $   (1.22) $   (2.09) $   (2.47) $   (1.90) $   (4.44) $   (0.57) $   (1.65)
  From extraordinary item.....................     --         --         --         --          (1.23)    --         --
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
Net loss attributable to common
  stockholders................................  $   (1.22) $   (2.09) $   (2.47) $   (1.90) $   (5.67) $   (0.57) $   (1.65)
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
Weighted average shares used in per share
  calculation:
  Basic and diluted...........................     10,252     13,641     15,514     22,620     23,054     22,783     23,186
</TABLE>
 
                                       24
<PAGE>
<TABLE>
<CAPTION>
                                                                                                        THREE MONTHS ENDED
                                                               YEAR ENDED DECEMBER 31,                      MARCH 31,
                                                -----------------------------------------------------  --------------------
                                                  1994       1995       1996       1997       1998       1998       1999
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
                                                                   (IN THOUSANDS, EXCEPT OPERATING DATA)
<S>                                             <C>        <C>        <C>        <C>        <C>        <C>        <C>
OTHER FINANCIAL DATA:
EBITDA........................................  $ (11,148) $ (20,265) $ (24,577) $ (26,563) $ (31,814) $  (6,821) $  (8,170)
Net cash used in operating activities.........    (11,571)   (18,489)   (26,331)   (22,525)   (60,318)   (10,771)   (21,578)
Net cash provided (used in) by investing
  activities..................................     (4,996)   (37,057)    (1,592)   (43,164)  (349,992)    16,455   (200,424)
Net cash provided by (used in) financing
  activities..................................     80,984     (2,306)    94,772     11,286    729,035       (209)   351,655
Capital additions.............................      3,672     11,378      9,800     40,214    220,903      2,716    161,590
 
OTHER OPERATING DATA:
  Billable minutes (000s).....................     14,981     25,932     62,249    140,918    383,875     52,418    270,808
  Switches....................................          2         10         13         14         15         14         15
  Points of presence..........................          3         11         13         33         34         33         45
  Route kilometers of owned intra-European
    fiber optic cable in operation............         --         --         --         --         --         --      1,850
<CAPTION>
 
                                                                 As of December 31,                      As of March 31,
                                                -----------------------------------------------------  --------------------
                                                  1994       1995       1996       1997       1998       1998       1999
                                                ---------  ---------  ---------  ---------  ---------  ---------  ---------
                                                                              (in thousands)
<S>                                             <C>        <C>        <C>        <C>        <C>        <C>        <C>
 
BALANCE SHEET DATA:
  Cash, cash equivalents and marketable
    securities................................    $66,762  $  35,066  $  92,982  $  47,143  $ 501,282  $  28,150  $ 498,755
  Restricted cash equivalents and restricted
    marketable securities.....................     --         --         --         --        144,523     --        229,796
  Cash securing letters of credit for network
    construction..............................     --         --         --         --         --         --        121,239
  Working capital.............................     58,549     26,214     79,434      7,666    428,657     12,729    427,217
  Property and equipment, net.................      6,933     15,715     21,074     54,094    266,256     56,997    409,909
  Intangible assets, net......................      5,225      5,502      5,021      4,339     46,968     12,567     70,579
  Total assets................................     83,923     65,613    134,664    126,809  1,009,111    121,894  1,411,990
  Long-term debt, excluding current
    installments..............................     59,955     67,283     77,904     99,610    921,139    102,360  1,292,482
  Redeemable convertible preferred stock......     --         --         --         --         47,121     --         48,298
  Stockholders' equity (deficiency)...........     10,985    (17,618)    38,483     (8,564)  (137,292)   (18,271)  (184,370)
</TABLE>
 
                                       25
<PAGE>
                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                 FINANCIAL CONDITION AND RESULTS OF OPERATIONS
 
    THE FOLLOWING DISCUSSION SHOULD BE READ IN CONJUNCTION WITH OUR FINANCIAL
STATEMENTS, THE NOTES THERETO, AND THE OTHER FINANCIAL DATA INCLUDED LATER IN
THIS PROSPECTUS. THE FOLLOWING DISCUSSION INCLUDES CERTAIN FORWARD-LOOKING
STATEMENTS. FOR A DISCUSSION OF IMPORTANT FACTORS, INCLUDING, BUT NOT LIMITED
TO, THE CONTINUED DEVELOPMENT OF OUR BUSINESS, ACTIONS OF REGULATORY AUTHORITIES
AND COMPETITORS, PRICE DECLINES AND OTHER FACTORS WHICH COULD CAUSE ACTUAL
RESULTS TO DIFFER MATERIALLY FROM THE RESULTS REFERRED TO IN THE FORWARD-LOOKING
STATEMENTS, SEE "RISK FACTORS."
 
OVERVIEW
 
    Since our inception in 1991, we have invested heavily in developing our
ability to provide international communications services within Western Europe
and to expand our market presence. During the past seven years, we have made
substantial investments in software and back office operations, an
administrative infrastructure and a direct sales organization in Western Europe.
Furthermore, we have created an extensive commercial telecommunications network
in Western Europe which we believe is necessary to economically render the voice
and data services we offer and intend to offer. We have also expanded our
ability to generate revenues in North America during 1998. Historically, our
revenues were derived from wholesale sales and retail sales (which is composed
of sales to end users). Currently, our revenues also include revenues from the
sale of capacity on our network. Each revenue source has a different impact on
our results of operations. The sale of capacity on the Circe Network will vary
substantially from period to period and will result in fluctuations in our
operating results. For a discussion of the effects of the Circe Network on
communication services revenue and other line items, see "--The Circe Network."
 
    REVENUE
 
    Our revenue is derived from communication services and capacity sales. Our
communications services revenue is currently based primarily on the number of
minutes of use billed ("billable minutes") and, to a lesser extent, on the
additional services and products provided through our network. We currently
derive our communication services revenue principally from long distance
telecommunications services.
 
    During recent years, the following key trends have affected the composition
of our communication services revenue:
 
    - A growing proportion of our customers, particularly in Western Europe, now
      access our network using either "indirect access" or "dedicated access"
      rather than call re-origination or international toll-free access (See
      "Business--The Viatel Network").
 
    - We have continued to expand our wholesale business. Our acquisition of
      Flat Rate Communications, Inc. during 1998 has resulted in a significant
      increase in our wholesale business, and has increased our revenues
      generated in North America. We believe that the revenues generated in
      North America will continue to increase.
 
    - The Western European market has increased in importance for us. In
      contrast, revenue from Latin America and Asia/Pacific Rim has declined,
      and is expected to continue to decline, as a percentage of total
      communications revenue as we continue to grow our business in Western
      Europe.
 
                                       26
<PAGE>
    The table set forth below presents our communication services revenue, as a
percentage of total revenue, from different regions (based on where calls
originated on the network):
 
<TABLE>
<CAPTION>
                                                                                                  THREE MONTHS ENDED
                                                                    YEAR ENDED DECEMBER 31,           MARCH 31,
                                                                -------------------------------  --------------------
<S>                                                             <C>        <C>        <C>        <C>        <C>
                                                                  1996       1997       1998       1998       1999
                                                                ---------  ---------  ---------  ---------  ---------
Western Europe................................................       39.5%      44.7%      46.6%      52.9%      67.2%
North America.................................................       18.9       21.9       41.6       26.9       28.0
Latin America.................................................       28.6       22.2       10.8       17.3        4.7
Asia/Pacific Rim and Other....................................       13.0       11.2        1.0        2.9        0.1
</TABLE>
 
    We have experienced, and expect to continue to experience, declining revenue
per minute in all of our markets, in part as a result of increasing worldwide
competition within the telecommunications industry. See "Risk Factors--Our
Industry is Highly Competitive With Participants That Have Greater Resources
Than We Do, and We May Not Be Able to Compete Successfully." We believe,
however, that the impact on our results of operations from price decreases will
be at least partially offset by (1) continuing decreases in our cost of
providing telecommunications services, particularly those decreases resulting
from our continued efforts to convert from leased to owned infrastructure and
reduce interconnection costs through the use of the Circe Network as it is
expanded, (2) the introduction of new products and services, and (3) our ability
to enter into additional interconnection agreements. There can be no assurance,
however, that the results referred to in the foregoing forward looking
statements, including a decline in our cost of communication services, can be
achieved.
 
    COST OF SERVICES AND SALES
 
    Our cost of services and sales can be classified into four general
categories: access costs, network costs, termination costs and cost of capacity
sold. Access costs generally represent the costs associated with transporting
the traffic from a customer's premises to the closest access point on our
network. Access costs vary depending upon the distance from our network to the
customer's premises and from country to country. We currently expect that our
effective per minute access costs will be reduced as deregulation continues and
competition accelerates, certain European Union directives requiring
cost-oriented pricing (i.e., costs that an effectively competitive market would
yield) by incumbent telecommunications operators are enforced and as we are able
to obtain cost effective interconnection agreements. However, we can provide no
assurance regarding the extent or timing of such cost decreases. In the event
that such access costs do not fall as fast as we expect or at all, our gross
margins could be adversely impacted.
 
    Network costs represent the costs of transporting calls over our network
from its point of entry to its point of exit. Network costs generally consist of
leased line rental costs, facility/network management costs and costs associated
with interconnection with facilities of incumbent telecommunications operators.
These costs will decrease substantially as each ring of the Circe Network is
placed into service and we secure infrastructure ownership on other routes,
which will enhance gross margins. However, there will be an associated increase
in depreciation and amortization expense (which is not included in network
costs). In order to succeed, we will need our per minute network costs to
decline substantially compared to our per minute revenue. See "--Depreciation
and Amortization."
 
    Termination costs currently represent the costs which we are required to pay
to other carriers from the point of exit from our network to the point of
destination. Termination costs are generally variable with traffic volume and
traffic mix. If a call is terminated in a city in which we have a switch or
point of presence, the call is usually transferred to the public switch
telephone network for local termination. If the call is to a location in which
we do not have a switch or point of presence, then the call must be transferred
to another carrier with which we are interconnected. See "--The Circe Network"
for a description of cost of capacity sold.
 
                                       27
<PAGE>
    We utilize least cost routing designed to terminate traffic in the most cost
effective manner. We believe that local termination costs should decrease as we
(1) add additional switches and points of presence, (2) interconnect with
additional incumbent telecommunications operators and other infrastructure
providers and (3) construct or purchase additional transmission facilities.
Local termination costs should also decrease as new telecommunications service
providers emerge and, in Western Europe, as European Union member states
implement and enforce regulations requiring incumbent telecommunications
operators to establish rates which are set at the forward-looking, long run
economic costs that would be incurred by an efficient provider using
state-of-the-art technology. We cannot provide any assurance regarding the
results referred to in the foregoing forward-looking statements, including the
extent or timing of cost decreases. See "Risk Factors" and
"Business--Competition" and "Business-- Government Regulation."
 
    SELLING, GENERAL AND ADMINISTRATIVE EXPENSES
 
    Our selling, general and administrative expenses include commissions paid to
independent sales representatives and overhead costs associated with our
headquarters, back office and network operations centers and sales offices. Our
selling, general and administrative expenses have continued to increase since
our inception as we developed and expanded our business, although these expenses
have fallen as a percentage of communications revenue. We anticipate that these
expenses will continue to increase as our business is expanded in the future,
however, we cannot provide any assurance that this will be the case. We
anticipate that these expenses will continue to be incurred in advance of
anticipated related communication services revenue.
 
    DEPRECIATION AND AMORTIZATION
 
    Depreciation and amortization expense includes charges relating to
depreciation of property and equipment, which consist principally of
telecommunications-related equipment such as switches and points of presence,
indefeasible rights of use and minimum investment units, furniture and
equipment, leasehold improvements, and amortization of intangibles assets,
including goodwill and costs associated with acquired employee base and sales
forces. We depreciate our network over periods ranging from five to 15 years and
amortize our intangible assets over periods ranging from three to 25 years. We
expect depreciation and amortization expense to increase as we further expand
our network, particularly as each ring of the Circe Network is placed into
service, at least until significant portions of the Circe Network are sold.
 
THE CIRCE NETWORK
 
    The Circe Network is expected to have significant effects on our results of
operations. The sale of capacity on the Circe Network will vary substantially
from period to period and, as a result, may result in fluctuations in our
operating results. During the first quarter of 1999, we began selling capacity
on the Circe Network. These sales substantially increase our gross profit (I.E.,
total revenue less cost of services and sales) because our cost of communication
services as a percentage of communications service revenues is currently higher
than the cost of capacity as a percentage of capacity sales. Due to the timing
of capacity sales and higher margin associated with such sales, our gross
profits and gross margin may also fluctuate substantially in the future, in ways
that will not necessarily reflect the trends in our communications services
business. We capitalize all of the costs associated with designing, building,
funding and placing each ring of the Circe Network into service.
 
    Revenue from capacity sales that qualify under generally accepted accounting
principles to be treated as sales are recognized under a line item titled
"Capacity sales." Capacity sales are recognized as revenue when the purchaser
obtains the right to use the capacity. The related cost of capacity is reported
in the same period. With respect to each sale of capacity, the related cost of
capacity sales is equal to a proportionate amount of the total capitalized cost
of the related network. Revenue from operating leases
 
                                       28
<PAGE>
of private line circuits will be included in communications services revenue and
will be recognized on a straight line basis over the life of the lease. The
portion of the total capitalized cost of the Circe Network used to provide
communication services is included in property and equipment and is being
charged to depreciation and amortization over its useful life.
 
    We expect to trade capacity on the Circe Network for capacity on other cable
systems. Depending upon structure, these trades of capacity may have a material
affect on our statement of operations. We will continue to incur sales and
marketing and related expenses that will not be capitalized and will affect our
results of operations, particularly while the Circe Network is being designed,
built and placed into service. In addition, we will continue to incur additional
operating and maintenance expense as the remaining Circe phases become
operational. As a result of financing the Circe Network with debt, we are
capitalizing a portion of the interest incurred that relates to the construction
of the Circe Network until it is placed in service and will incur increases in
interest expense thereafter.
 
    The Circe Network will have a beneficial effect on our costs of services and
sales as well as net income (loss). This will occur as we bring traffic
"on-net," to facilities we own, as opposed to facilities that we lease from
other carriers. A large portion of the expenses associated with facilities we
own is accounted as depreciation and amortization, while leased capacity is
accounted for as a cost of services and sales. As a result, we expect that our
gross margins and profit will be improved as we bring traffic "on-net". However,
our net income (loss) will not improve to the same extent. The effect of
bringing traffic "on-net" will be somewhat delayed, because our leased line
agreements require minimum notification to terminate our obligations.
 
RESULTS OF OPERATIONS
 
    The following table summarizes the breakdown of our results of operations as
a percentage of total revenue. Our total revenue, and therefore these
percentages, could fluctuate substantially from period to period due to capacity
sales, which have a substantially different impact on margins than
communications services.
 
<TABLE>
<CAPTION>
                                                                                            THREE MONTHS
                                                           YEAR ENDED DECEMBER 31,        ENDED MARCH 31,
                                                       -------------------------------  --------------------
<S>                                                    <C>        <C>        <C>        <C>        <C>
                                                         1996       1997       1998       1998       1999
                                                       ---------  ---------  ---------  ---------  ---------
Cost of services and sales...........................      83.6%      87.0%      90.3%      90.0%      82.8%
Selling, general and administrative expenses.........      65.2%      49.4%      33.2%      42.2%      30.4%
Depreciation and amortization........................       9.5%      10.6%      12.0%      13.7%      15.6%
EBITDA loss(1).......................................     (48.7%)    (36.4%)    (23.5%)    (32.1%)    (13.3%)
</TABLE>
 
- ------------------------
 
(1) As used herein "EBITDA" consists of earnings before interest, income taxes,
    extraordinary loss, dividends on convertible preferred stock and
    depreciation and amortization. EBITDA is a measure commonly used in the
    telecommunications industry to analyze companies on the basis of operating
    performance. EBITDA is not a measure of financial performance under
    generally accepted accounting principles, is not necessarily comparable to
    similarly titled measures of other companies and should not be considered as
    an alternative to net income as a measure of performance nor as an
    alternative to cash flow as a measure of liquidity.
 
THREE MONTHS ENDED MARCH 31, 1999 COMPARED TO THE THREE MONTHS ENDED MARCH 31,
  1998
 
    TOTAL REVENUE.  Total revenue increased by 190.2% to $61.6 million for the
three months ended March 31, 1999 from $21.2 million for the three months ended
March 31, 1998. Within this growth was a 127.9% increase in communication
services revenue to $48.4 on 270.8 million billable minutes for the first
quarter of 1999 from $21.2 million on 52.4 million billable minutes for the
first quarter of 1998. Capacity sales were $13.2 million for the first quarter
of 1999. We had no capacity sales during the first quarter of
 
                                       29
<PAGE>
1998, because the Circe Network did not exist. Revenue growth for the first
quarter of 1999 was generated primarily by growth from European end user
revenues and new capacity sales.
 
    A substantial increase in billable minutes from the first quarter of 1998 to
the first quarter of 1999 was partially offset by a substantial decline in
revenue per billable minute primarily because of (i) a higher percentage of
lower-priced intra-European and national long distance traffic on our network
and (ii) reductions in prices in response to price reductions by incumbent
telecommunications operators and other competitors in many of the Company's
markets.
 
    Communication services revenue per billable minute from the sale of services
to retail customers, which represented 44.3% of total revenue for the three
months ended March 31, 1999, compared to 55.2% for the three months ended March
31, 1998, decreased 72.5% to $.14 in the first quarter of 1999 from $.51 in the
first quarter of 1998. Communication services revenue per billable minute from
the sale of services to carriers and other resellers remained constant at $.29
for the first quarter of 1999 and in the first quarter of 1998.
 
    During the first quarter of 1999 as compared to the first quarter of 1998,
we increased our carrier business (through which we provide switched minutes,
private lines and ports to carriers, Internet Service Providers and other
resellers) on an absolute basis. However, our carrier business has declined as a
percentage of communications service revenue, because our retail services grew
at a faster rate. The carrier business represented approximately 34.2% of total
revenue and approximately 27.1% of billable minutes for the three months ended
March 31, 1999 as compared to approximately 44.6% of total revenue and
approximately 56.2% of billable minutes for the three months ended March 31,
1998.
 
    COST OF SERVICES AND SALES.  Cost of services and sales increased to $51.0
million in the first quarter of 1999 from $19.1 million in the first quarter of
1998. As a percentage of total revenue, however, cost of services and sales
decreased to approximately 82.8% from approximately 90.0% for the three months
ended March 31, 1999 and 1998, respectively. Cost of services and sales for the
three months ended March 31, 1999 includes costs associated with the sale of
capacity on the Circe Network. These costs did not occur in the first quarter of
1998. The cost of the sold capacity represented non-cash charges of the pro rata
cost of the network asset and is determined based upon the ratio of total
capacity sold to total estimated capacity multiplied by the total capitalized
costs of the related network. Our gross margin increased, as a result of
capacity sales to 17.2% for the three months ended March 31, 1999 as compared to
10.0% for the three months ended March 31, 1998.
 
    Cost of services and sales continued to increase in the three months ended
March 31, 1999 in part because of the relatively high cost of leased
infrastructure and the increase in minutes. These costs are expected to decrease
as a percentage of revenue as we migrate from leased infrastructure to the Circe
Network and other owned capacity. The effect of bringing traffic "on-net" will
be somewhat delayed, because our leased line agreements require minimum
notification to terminate our obligations.
 
    SELLING, GENERAL AND ADMINISTRATIVE EXPENSES.  Selling, general and
administrative expenses increased to $18.8 million in the three months ended
March 31, 1999 from $9.0 million in the three months ended March 31, 1998 and,
as a percentage of total revenue, decreased to approximately 30.4% in the three
months ended March 31, 1999 from approximately 42.2% in the corresponding period
in 1998. Much of these expenses are attributable to overhead costs associated
with our headquarters, back office and operations as well as maintaining a
physical presence in seventeen different jurisdictions. We expect to incur
additional expenses as we continue to invest in operating infrastructure and
actively market our products and services. Salaries and commissions, as a
percentage of total selling, general and administrative expenses, were
approximately 47.5% and 52.3% for the three months ended March 31, 1999 and
1998, respectively. Advertising and promotion expenses, as a percentage of total
selling, general and administrative expenses, were approximately 5.1% and 1.1%
for the three months ended March 31, 1999 and 1998, respectively.
 
                                       30
<PAGE>
    EBITDA LOSS.  EBITDA loss increased to $8.2 million for the three months
ended March 31, 1999 from $6.8 million for the three months ended March 31,
1998. As a percentage of total revenue, EBITDA loss decreased to approximately
13.3% in the first quarter of 1999 from approximately 32.1% in the first quarter
of 1998. We expect gross margin to improve as we migrate traffic from leased
lines to our own network.
 
    DEPRECIATION AND AMORTIZATION.  Depreciation and amortization expense, which
includes depreciation of the network, increased to approximately $9.6 million in
the three months ended March 31, 1999 from approximately $2.9 million in the
three months ended March 31, 1998. The increase was due primarily to the $367.8
million increase in gross property and equipment from $72.2 million at March 31,
1998 to $440.0 million at March 31, 1999. Depreciation expense will increase
substantially as each additional ring of the Circe Network becomes operational.
 
    INTEREST.  Interest expense increased from approximately $3.8 million in the
three months ended March 31, 1998 to approximately $26.2 million in the three
months ended March 31, 1999 primarily as a result of our aggregate debt, which
includes notes and capital lease obligations, increasing from $104.2 million at
March 31, 1998 to $1.3 billion at March 31, 1999. During the three months ended
March 31, 1999, we capitalized $2.3 million of interest costs. Interest income
increased from approximately $510,000 in the three months ended March 31, 1998
to approximately $6.8 million in the three months ended March 31, 1999 primarily
as a result of the interim investment of the net proceeds from our 1998 high
yield offering.
 
1998 COMPARED TO 1997
 
    TOTAL REVENUE
 
    Total revenue increased by 85.1% from $73.0 million on 140.9 million
billable minutes for 1997 to $135.2 million on 383.9 million billable minutes
for 1998. Total revenue growth for 1998 was generated primarily from increased
European retail traffic and growth in our carrier business in Western Europe and
in North America which was partially offset by decreased revenue from our
Pacific Rim and Latin American operations.
 
    The overall increase of 172.4% in billable minutes from 1997 to 1998 was
partially offset by declining revenue per billable minute, primarily because of
(1) a higher percentage of lower-priced intra-European and international long
distance traffic on our network as compared to intercontinental traffic, (2) a
higher percentage of lower-priced carrier traffic as compared to retail traffic
and (3) reductions in certain rates charged to retail customers in response to
pricing reductions enacted by incumbent telecommunications operators and other
carriers in many of Viatel's markets. See "--Cost of Communication Services and
Capacity."
 
    Communication services revenue per billable minute from the sale of services
to retail customers, which represented 72.1% of total revenue for 1997, compared
to 41.7% for 1998, decreased 43.5% from $.69 in 1997 to $.39 in 1998. Total
revenue per billable minute from the sale of services to carriers and other
resellers increased by 3.3% from $.30 in 1997 to $.31 in 1998 due primarily to
changes in traffic mix. The number of contracted customers billed declined 30.2%
from 21,515 at December 31, 1997 to 15,010 at December 31, 1998. This decline in
contracted customers billed is primarily attributable to our Pacific Rim
operations where the number of customers billed declined 93.2% from 5,424 at
December 31, 1997 to 369 at December 31, 1998, representing a net loss of 5,055
customers, as a result of currency fluctuations caused by the Asian economic
crisis, which made our rates noncompetitive.
 
    During 1998, approximately 46.6% of our total revenue was generated in
Western Europe as compared to approximately 44.7% of the company's communication
services revenue during 1997. Total revenue from Latin America represented
approximately 10.8% of our total revenue during 1998 compared
 
                                       31
<PAGE>
to approximately 22.2% of our total revenue during 1997. Total revenue from the
Pacific Rim represented approximately 1.0% of our total revenue during 1998 as
compared to approximately 11.2% during 1997.
 
    During 1998 as compared to 1997, we significantly increased our carrier
business through which we sell switched minutes, private lines and ports to
carriers, Internet service providers and other resellers. The carrier business
has enabled us to recover partially the costs associated with increased capacity
in advance of demand from retail customers. The resulting economies of scale
have allowed us to use our network more profitably for network originations and
terminations within Europe. The carrier business represented approximately 27.9%
of total revenue and approximately 46.1% of billable minutes for 1997 as
compared to approximately 58.3% of total revenue and approximately 62.0% of
billable minutes for 1998. The increase in total revenue derived from carriers
and other resellers is partially attributable to the acquisition of Flat Rate
Communications, Inc., a long distance telecommunications reseller, on February
27, 1998 which also significantly increased our North American revenues.
 
    COST OF SERVICES
 
    Cost of services increased from $63.5 million in 1997 to $122.1 million in
1998 and, as a percentage of total revenue, increased from approximately 87.0%
to approximately 90.3%. Our gross margin decreased, as a percentage of total
revenue, from 13.0% for 1997 to 9.7% for 1998. This expected decrease was
primarily due to (1) decreased revenue per minute resulting from price
competition and foreign currency fluctuations which was not offset by
corresponding decreases in infrastructure costs, (2) increased sales to carrier
customers which generate substantially lower margins, and (3) an increase in
intra-European and national long distance traffic compared to higher margin
international traffic. This decrease in gross margin, as a percentage of
revenue, is one of the principal reasons we initiated a strategy to own key
elements of our network infrastructure.
 
    Cost of services increased in 1998 in part because of the relatively high
cost of leased infrastructure. These costs are expected to decrease as a
percentage of total revenue as we continue to migrate from leased infrastructure
to owned infrastructure. From 1997 to 1998, we increased our private line
circuits capacity and, as a result, costs for private line circuits increased
from approximately $9.6 million for 1997 (approximately 13.1% of total revenue)
to approximately $17.1 million for 1998 (approximately 12.6% of total revenue).
 
    SELLING, GENERAL AND ADMINISTRATIVE EXPENSES
 
    Selling, general and administrative expenses increased from $36.1 million in
1997 to $44.9 million in 1998 and, as a percentage of total revenue, decreased
from approximately 49.4% in 1997 to approximately 33.2% in 1998. Much of these
expenses are attributable to overhead costs associated with our headquarters,
back office and network operations as well as maintaining sales offices.
Salaries and commissions, as a percentage of total selling, general and
administrative expenses, were approximately 51.6% and 49.3% for 1997 and 1998,
respectively. Advertising and promotion expenses, as a percentage of total
selling, general and administrative expenses, were approximately 1.2% and 3.6%
for 1997 and 1998, respectively. We expect to incur additional expenses as we
continue to invest in our sales and marketing infrastructure and actively market
our products and services.
 
    EBITDA LOSS
 
    EBITDA loss increased from $26.6 million for 1997 to $31.8 million for 1998.
As a percentage of total revenue, EBITDA loss decreased from approximately 36.4%
in 1997 to approximately 23.5% in 1998. These losses resulted from lower gross
margins as a percentage of total revenue due to the relatively high cost of
intra-European leased lines which was compounded by the impact on revenue of
aggressive price reductions implemented by incumbent telecommunications
operators.
 
                                       32
<PAGE>
    DEPRECIATION AND AMORTIZATION
 
    Depreciation and amortization expense, which includes depreciation of our
network, increased from approximately $7.7 million in 1997 to approximately
$16.3 million in 1998. The increase was due primarily to (i) the depreciation of
equipment related to network expansion and fiber optic cable systems placed in
service during 1997 and (ii) the amortization of goodwill associated with the
acquisition of Flat Rate Communications, Inc. in February 1998. Depreciation
expense will increase substantially as each ring of the Circe Network becomes
operational.
 
    INTEREST
 
    Interest expense increased from approximately $12.5 million in 1997 to
approximately $79.2 million in 1998 primarily as a result of our high yield
offering completed in April 1998. Interest income increased from approximately
$3.7 million in 1997 to approximately $28.3 million for 1998 primarily as a
result of the interim investment of the net proceeds from our 1998 high yield
offering. During 1998, we capitalized $3.3 million of interest costs.
 
1997 COMPARED TO 1996
 
    TOTAL REVENUE
 
    Total revenue increased by 44.8% from $50.4 million on 62.2 million billable
minutes for 1996 to $73.0 million on 140.9 million billable minutes for 1997.
Total revenue growth for 1997 was generated primarily from increased traffic
volume on our network, from growth in our carrier business and, to a lesser
extent, increased traffic volume in Latin America and the Pacific Rim.
 
    The overall increase of 126.4% in billable minutes from 1996 to 1997 was
partially offset by declining revenue per billable minute primarily because of
(1) a higher percentage of lower-priced intra-European and national long
distance traffic from our network as compared to intercontinental traffic, (2) a
higher percentage of lower-priced carrier traffic as compared to retail traffic,
(3) reductions in certain rates charged to retail customers in response to
pricing reductions enacted by certain incumbent telecommunications operators and
other carriers in many of our markets, (4) changes in customer access methods
and (5) foreign currency fluctuations. See "--Cost of Communication Services and
Capacity."
 
    Total revenue per billable minute from the sale of services to retail
customers, which represented 83.5% of total revenue in 1996, compared to 72.1%
in 1997, decreased from $1.04 in 1996 to $.69 in 1997. Total revenue per
billable minute from the sale of services to carriers and other resellers
decreased from $.38 in 1996 to $.30 in 1997, primarily as a result of price
competition. The number of customers billed rose 18.4% from 18,172 at December
31, 1996 to 21,515 at December 31, 1997.
 
    During 1997, approximately 44.7% of our total revenue was generated in
Western Europe as compared to approximately 41.9% of our total revenue in 1996.
Despite an increase of approximately 14.1% over 1996, total revenue from Latin
America represented approximately 22.2% of our total revenue during 1997 as
compared to approximately 28.4% of our total revenue during 1996. Total revenue
from the Pacific Rim represented approximately 12.4% of our total revenue during
1996 as compared to approximately 11.2% of our total revenue in 1997.
 
    The carrier business represented approximately 16.5% of total revenue and
approximately 35.2% of billable minutes for 1996 as compared to approximately
27.9% of total revenue and approximately 46.1% of billable minutes for 1997.
This increase in total revenue represents an increase of approximately 147.0%
over 1996.
 
                                       33
<PAGE>
    COST OF SERVICES
 
    Cost of services increased from $42.1 million in 1996 to $63.5 million in
1997 and, as a percentage of total revenue, increased from approximately 83.6%
to approximately 87.0% for 1996 and 1997, respectively. Our gross margin
decreased from 16.4% for 1996 to 13% for 1997. This decrease was primarily due
to (1) decreased revenue per minute resulting from price competition and foreign
currency fluctuations which were not offset by corresponding decreases in
infrastructure costs, (2) increased sales to carrier customers which generate
substantially lower margins, and (3) an increase in intra-European and national
long distance traffic compared to higher margin international traffic.
 
    Cost of services increased in 1997 because of the relatively high cost of
leased infrastructure and the accelerated rollout of European points of
presence. These costs are expected to decrease as a percentage of total revenue
as we continue our efforts to convert from leased to owned capacity. We
increased our private line circuits capacity by 311%, and as a result the fixed
costs associated with our network, costs for private line circuits increased
from approximately $4.1 million for 1996 (approximately 8.2% of total revenue)
to approximately $6.0 million for 1997 (approximately 8.2% of total revenue).
 
    SELLING, GENERAL AND ADMINISTRATIVE EXPENSES
 
    Selling, general and administrative expenses increased from $32.9 million in
1996 to $36.1 million in 1997 and, as a percentage of total revenue, decreased
from approximately 65.2% in 1996 to approximately 49.4% in 1997. Much of these
expenses are attributable to overhead costs associated with our headquarters,
back office and network operations as well as maintaining a physical presence in
seventeen different jurisdictions. Salaries and commissions, as a percentage of
total selling, general and administrative expenses, were approximately 49.0% and
51.6% for 1996 and 1997, respectively.
 
    EBITDA LOSS
 
    EBITDA loss increased from $24.6 million for 1996 to $26.6 million for 1997.
As a percentage of total revenue, EBITDA loss decreased from approximately 48.7%
in 1996 to approximately 36.4% in 1997. These losses resulted from lower gross
margins as a percentage of total revenue due to the relatively high cost of
intra-European leased lines which was compounded by the impact on revenue of
aggressive price reductions implemented by certain incumbent telecommunications
operators.
 
    DEPRECIATION AND AMORTIZATION
 
    Depreciation and amortization expense, which includes depreciation of our
network, increased from approximately $4.8 million in 1996 to approximately $7.7
million in 1997. The increase was due primarily to the depreciation of equipment
related to network expansion and fiber optic cable systems placed in service
during 1997.
 
    INTEREST
 
    Interest expense increased from approximately $10.8 million in 1996 to
approximately $12.5 million in 1997 due to the accretion of non-cash interest on
the notes we issued in 1994. Interest income increased from approximately $1.9
million for 1996 to approximately $3.7 million in 1997, primarily as a result of
the investment of the net proceeds from our initial public offering.
 
LIQUIDITY AND CAPITAL RESOURCES
 
    We have incurred losses from operating activities in each year of operations
since our inception and expect to continue to incur operating and net losses for
the next several years. Since inception, we have utilized cash provided by
financing activities to fund operating losses, interest expense and capital
expenditures. The sources of this cash have primarily been through private and
public equity and debt
 
                                       34
<PAGE>
financings and, to a lesser extent, equipment-based financing. As of March 31,
1999, we had $620.0 million of cash, cash equivalents, cash securing letters of
credit for network construction and marketable securities and $229.8 million of
restricted cash equivalents and other restricted marketable securities, which
secure interest payments on our notes through April 2001.
 
    On March 19, 1999 we completed a high yield offering through which we raised
approximately $365.5 million of gross proceeds in a combination of senior dollar
notes and senior Euro notes.
 
    On April 8, 1998, we completed a high yield offering through which we raised
approximately $889.6 million of gross proceeds ($856.6 million of net proceeds).
A portion of the proceeds from this high yield offering were utilized by us to
retire our 15% senior discount notes due 2005 pursuant to a tender offer.
 
    We believe that the net proceeds from this offering and the 1999 high yield
offering, together with cash and marketable securities on hand and future sales
of capacity on the Circe Network, will provide sufficient funds for us to expand
our business as planned and to fund operating losses for at least the next 12 to
18 months. However, the amount of our future capital requirements will depend on
a number of factors, including the success of our business, the start-up dates
of each ring of the Circe Network, the dates at which we further expand our
network, the types of services we offer, staffing levels, acquisitions and
customer growth as well as other factors that are not within our control,
including competitive conditions, government regulatory developments and capital
costs. In the event our plan or assumptions change or prove to be inaccurate, we
are unable to convert from leased to owned infrastructure in accordance with our
current plans or the net proceeds of this offering, cash and investments on
hand, equity offerings and the proceeds from the sale of capacity on the Circe
Network prove to be insufficient to fund our growth in the manner and at the
rate currently anticipated, we may be required to delay or abandon some or all
of our development and expansion plans or we may be required to seek additional
sources of financing earlier than currently anticipated. In the event we are
required to seek additional financing, there can be no assurance that such
financing will be available on acceptable terms or at all.
 
    CAPITAL ADDITIONS; COMMITMENTS
 
    The development of our business has required substantial capital. Capital
additions for each period consist of capital expenditures, the net increase in
property and equipment purchases payable, assets acquired under capital lease
obligations and capitalized interest during the period. During 1998, capital
additions totalled $220.9 and consisted of capital expenditures of approximately
$94.7 million, a net increase of $92.5 million in property and equipment
purchases payable, $30.4 million of assets acquired under capital lease
obligations and capitalized interest of $3.3 million. During the three months
ended March 31, 1999, we had capital additions of $161.6 million, which
consisted of capital expenditures of approximately $101.7 million, a net
increase of $44.1 million in property and equipment purchases payable, $13.6
million of assets acquired under capital lease obligations and capitalized
interest of $2.3 million. We have also entered into certain agreements
associated with the Circe Network, purchase commitments for network expansion
and other items aggregating in excess of $225.0 million at March 31, 1999.
Additionally, we have minimum volume commitments to purchase transmission
capacity from various domestic and foreign carriers aggregating approximately
$13.2 million for all of 1999.
 
    Based upon certain key operating performance targets which were met during
the period ended March 31, 1999, we recognized our obligation to pay contingent
consideration for our 1998 Flat Rate acquisition.
 
    On May 13, 1999, our Series A preferred stock and our subordinated
debentures converted into shares of our common stock. The conversion was based
upon maintenance of our common stock above a certain per share price for a
specified time period. The Series A preferred stock and the subordinated
debentures converted at a conversion price equal to $13.20 and DM24.473,
respectively, at the then
 
                                       35
<PAGE>
applicable exchange rate. Accordingly, we issued approximately 4.6 million
shares of our common stock and will pay cash for any fractional shares due upon
conversion.
 
    FOREIGN CURRENCY
 
    We have exposure to fluctuations in foreign currencies relative to the U.S.
Dollar as a result of billing portions of our communication services revenue in
the local European currency in countries where the local currency is relatively
stable while many of our obligations, including a substantial portion of our
transmission costs, are denominated in U.S. Dollars. In countries with less
stable currencies, such as Brazil, we bill in U.S. Dollars. Debt service on
certain of the notes issued by us are currently payable in Euros. A substantial
portion of our capital expenditures are and will continue to be denominated in
various European currencies, including the Euro. Most of the European currencies
in which we do business converged effective January 1, 1999, with the exception
of the British Pound Sterling.
 
    With the continued expansion of our network, a substantial portion of the
costs associated with the network, such as local access and termination charges
and a portion of the leased line costs, as well as a majority of local selling
expenses and debt service related to the Euro denominated notes, will be charged
to us in the same currencies as revenue is billed. These developments create a
natural hedge against a portion of our foreign exchange exposure. To date, much
of the funding necessary to establish the local direct sales organizations has
been derived from communication services revenue that was billed in local
currencies. Consequently, our financial position as of March 31, 1999 and our
results of operations for the three months ended March 31, 1999 were not
significantly impacted by fluctuations in the U.S. Dollar in relation to foreign
currencies.
 
YEAR 2000
 
    The Year 2000 problem is the result of computer programs, microprocessors
and embedded date reliant systems using two digits rather than four to define
the applicable year. If these programs are not corrected, such date sensitive
computer programs, microprocessors and embedded systems may recognize a date
using "00" as the year 1900 rather than the year 2000. This could result in a
system failure or miscalculation causing disruptions in operations.
 
    In an effort to assess our Year 2000 state of readiness, during 1997 we
began performing a complete inventory assessment of all of our internal systems,
which we have divided into two categories, business essential, or mission
critical, and support systems, or non-mission critical. As part of our Year 2000
program and as part of our overall procurement plan, we have sought to ensure
that fixed assets acquired were Year 2000 compliant. At December 31, 1997 gross
property and equipment was $67.0 million compared to $440.0 million at March 31,
1999, an increase of 556.7 percent in gross property and equipment. As part of
this process, we have inventoried, tested, and ensured Year 2000 compliance of
our mission critical systems. The inventory and testing of these mission
critical systems is complete. The backbone of our communications network is
primarily composed of Nortel switches which are Year 2000 compliant. Our message
processing and billing systems, which are used to record and process millions of
call detail records, and our transmission equipment are also Year 2000
compliant. The majority of our non-mission critical systems are Year 2000
compliant. We anticipate our non-mission critical systems being Year 2000
compliant during the third quarter of 1999. The total estimated cost of ensuring
our preparation for Year 2000 is approximately $200,000, a portion of which has
already been incurred and expensed.
 
    We have initiated formal communications with the key carriers and other
vendors on which our operations and infrastructure are dependent to determine
the extent to which we are susceptible to a failure resulting from such third
parties' inability to remediate their own Year 2000 problems. Accordingly,
during the procurement process, we have taken steps to ensure that our vending,
carriers and products purchased are Year 2000 compliant or are adequately
addressing the Year 2000 issues. We can provide no assurance that the carriers
and other vendors on which our operations and infrastructure rely are or will be
 
                                       36
<PAGE>
Year 2000 compliant in a timely manner. Interruptions in the services provided
to us by these third parties could result in disruptions in our services.
Depending upon the extent and duration of any such disruptions and the specific
services affected, such disruptions could have a material adverse affect on our
business, financial condition and results of operations. As a contingency
against any possible disruptions in services provided by vendors, we have sought
to diversify our vendor base. We believe that the diversity of our vendor base
is sufficient to mitigate Year 2000 related disruptions in service to our
customers. In addition, we believe that the fact that we conduct business in,
and derive revenue from, multiple Western European countries helps to mitigate
the potential impact of Year 2000 related disruptions.
 
    In addition, disruptions in the economy generally resulting from the Year
2000 problems could also have a material adverse effect on us. We could be
subject to litigation resulting from any disruption in our services. The amount
of potential liability or lost revenue which would result from these disruptions
in service.
 
EURO
 
    On January 1, 1999, eleven of the fifteen member countries of the European
Union established irrevocable fixed conversion rates between their existing
sovereign currencies and a single currency called the Euro. The sovereign
currencies are scheduled to remain legal tender as denominations of the Euro
during a transition period from January 1, 1999 to January 1, 2002.
 
    We have completed an internal analysis regarding business and systems issues
related to the Euro conversion and, as a result, made necessary modifications to
our business processes and software applications. We are now able to conduct
business in both Euro and sovereign currencies on a parallel basis, as required
by the European Union.
 
    We believe that the Euro conversion has not and will not have a significant
impact on our business strategy in Europe. The costs to convert all systems to
be Euro compliant did not have a significant impact on our results of
operations.
 
INFLATION
 
    We do not believe that inflation has had a significant effect on our
operations to date.
 
PROSPECTIVE ACCOUNTING PRONOUNCEMENTS
 
    Statement of Financial Accounting Standards No. 133 ("SFAS 133"),
"Accounting for Derivative Instruments and Hedging Activities," was issued in
June 1998. SFAS 133 standardizes the accounting for derivative instruments,
including certain derivative instruments embedded in other contracts, by
requiring recognition of those instruments as assets and liabilities and to
measure them at fair value. While scheduled to be effective for us in the year
2000, there is a proposal to delay the implementation of the statement for one
year. We have not completed our analysis of the impact of this statement on our
financial statements.
 
MARKET RISK EXPOSURE
 
    We are subject to foreign currency exchange rate risk relating to receipts
from customers, payments to suppliers and interest and principal payments on the
outstanding Euro denominated senior notes, senior discount notes and
subordinated convertible debentures in foreign currencies. We do not consider
the market risk exposure relating to foreign currency exchange to be material.
See "--Liquidity and Capital Resources-Foreign Currency."
 
    We have financial instruments that are subject to interest rate risk,
principally short-term investments and debt obligations issued at a fixed rate.
Historically, we have not experienced material gains or losses due to interest
rate changes when selling short-term investments and typically hold these
securities until maturity. Based on our current holdings of short-term
investments, our exposure to interest rate risk is not material. Fixed-rate debt
obligations issued by us are generally not callable until maturity.
 
                                       37
<PAGE>
                                    BUSINESS
 
OVERVIEW
 
    We are a rapidly growing international communications company providing high
quality, competitively priced, long distance communication and data services to
end users, carriers and resellers. Our revenue has grown from $32.3 million in
1995 to $135.2 million in 1998, and today we have direct sales forces in twelve
Western European cities and an indirect sales force in more than 180 locations
in Western Europe.
 
    To capitalize on the opportunities presented by deregulation of the
telecommunications industry in Western Europe, we established an early presence
and sought aggressively to acquire licenses, interconnection and infrastructure.
Today, we have licenses in each of Belgium, France, Germany, Italy, The
Netherlands and the United Kingdom and interconnection agreements with the
incumbent telecommunications operator in each of these countries. We also have
licenses in Spain and Switzerland and expect to obtain interconnection
agreements in these countries during the fourth quarter of 1999.
 
    We currently operate one of Europe's largest pan-European networks, with
points of presence in 45 cities. We believe that control of network
infrastructure is critical to becoming a high quality, low-cost provider of
communications services because it will enable us to better manage service
offerings, quality of transmission and costs. Accordingly, we are currently in
the process of migrating from a network composed of international and domestic
leased circuits to a network composed primarily of owned circuits. To facilitate
this transition, in 1998 we commenced construction of a five-ring fiber optic
network in the largest telecommunications markets in Europe. These five rings,
which are expected to consist of approximately 8,700 route kilometers comprise
our Circe Network. In March 1999, we completed construction of phase one of the
Circe Network, which connects five European countries and includes London,
Paris, Amiens, Brussels, Antwerp, Rotterdam and Amsterdam, and have begun
construction of phases two and three.
 
    We believe, and our experience to date has indicated, that demand from end
users, carriers and other communications companies for high quality transmission
capacity in Europe will increase over the next several years due to fundamental
changes in the communications industry brought about by regulatory and technical
improvements. We also believe that cost effective transmission capacity in
Europe will allow new capacity intensive applications to be created which will,
in turn, fuel the need for additional capacity. Our network should allow us to
meet this increased demand by providing abundant transmission capacity for:
 
    - continued growth in our existing long distance voice service business,
 
    - additional provision of wholesale services to the large base of resellers
      that is developing as deregulation continues in Western Europe,
 
    - Internet, electronic commerce, multi-media and video services and other
      new technologies and applications, and
 
    - asynchronous transfer mode, frame relay, Internet protocol and other high
      speed data transmission services.
 
    As part of our strategy to capture a share of the rapidly growing data
market, in the first quarter of 1999 we entered into an arrangement with Lucent
pursuant to which Lucent is installing asynchronous transfer mode backbone
network equipment on our Circe Network. This backbone equipment is designed to
enable us to provide packet switched voice, video conferencing, private
intranets and dedicated Internet protocol transport over an integrated platform
and offer end users high capacity, speed and reliability. Lucent has agreed to
cooperate with us in developing marketing strategies to promote our data
services, to train our personnel and to assist us in achieving
network-to-network interfaces with certain specified carriers. We expect our
data network to be commercially operable in the fourth quarter of 1999.
 
                                       38
<PAGE>
MARKET OPPORTUNITIES
 
    International telecommunications is one of the fastest growing segments of
the long distance industry, having experienced a compounded growth in total
minutes of 15.5% per annum from 1988 to 1998. In 1997, according to industry
sources, the European international long distance market for voice services was
the largest in the world, with approximately 29.6 billion minutes or 43% of
international calling volume originating in Europe. A substantial portion of the
traffic originating in Europe terminates in Europe or the United States, where
we have international gateway switches.
 
INTERNATIONAL TRAFFIC PATTERNS
 
<TABLE>
<CAPTION>
                                                                                     DESTINATION
                                                                       ---------------------------------------
COUNTRY (MARKET DATA AS OF)                                               EUROPE*         USA         OTHER
                                                    OUTGOING MINUTES   -------------      ---      -----------
                                                    -----------------
                                                      (IN MILLIONS)
<S>                                                 <C>                <C>            <C>          <C>
United Kingdom (1997/1998)........................          5,800               52%           13%          35%
Germany (1997)....................................          5,333               52             6           42
France (1997).....................................          3,545               64             6           30
Italy (1997)......................................          2,352               57            11           32
Switzerland (1997)................................          2,164               70             4           26
Netherlands (1997)................................          1,535               75             6           19
Belgium (1996)....................................          1,228               85             4           11
Spain (1995)......................................          1,025               70             5           25
</TABLE>
 
- ------------------------
 
*   Europe-EU member states and Switzerland.
 
Source:  TeleGeography 1999.
 
    In 1997, the market for total domestic and international long distance in
the Western European countries in which we operate represented approximately
$104.3 billion, with $87.4 billion representing national long distance and
approximately $16.9 billion representing international long distance (Source:
"The European Telecommunications Fact File 1998"). In many European Union member
states, the ability to provide telecommunications services was liberalized on
January 1, 1998. We believe that regulatory liberalization in Western Europe and
technological advancements eventually will lead to market developments similar
to those that have occurred in the United States and the United Kingdom
following deregulation, including an increase in both international and national
traffic volume, reduced prices, increased service offerings and the emergence of
new entrants. By 1997, new entrants had amassed approximately 56.4% of the
United States international long distance market, from approximately 2.7% in
1985. (Source: FCC Common Carrier Bureau). In addition, from 1991 to July 1998
the number of licensed long distance competitors in the United Kingdom grew from
2 to 144. (Source: TeleGeography, 1999).
 
    We believe that there continues to be a shortage of cross-border capacity in
Europe. Most infrastructure in Europe is owned and operated by the incumbent
telecommunications operator. Under the traditional system of carrying
cross-border telecommunications traffic in Europe, the incumbent
telecommunications operators did not develop end-to-end cross-border circuits,
but rather connected their national networks with other carriers at the border
pursuant to bilateral agreements. We believe the system of bilateralism resulted
in a serious shortage of cross-border capacity in Europe. We also believe that
cost effective transmission capacity in Europe will allow new capacity intensive
applications to be created which will, in turn, fuel the need for additional
capacity.
 
    We believe that a substantial part of the capacity on existing routes has a
number of deficiencies including (1) high costs, (2) lack of end-to-end quality
control, (3) limited availability of capacity, (4) long lead times for
provisioning, (5) lack of redundancy and (6) long delays for restoration. While
there have been significant reductions in leased line costs as a result of
deregulation, these deficiencies are exacerbated by the increase in demand for
capacity from new entrants, thereby resulting in artificially and
 
                                       39
<PAGE>
significantly higher costs. We believe there is a significant opportunity to
provide high quality, cost-effective capacity to new entrants.
 
BUSINESS STRATEGY
 
    Our goal is to become a fully integrated communications company that is well
positioned to take advantage of growth opportunities in the European
communications industry. We believe that we can accomplish this goal by becoming
a low-cost provider of services through the ownership of key network
infrastructure. The key elements of our strategy include:
 
    - CAPITALIZE ON DEREGULATION IN LARGE EUROPEAN MARKETS. Our principal focus
      is on exploiting both international and national long distance
      opportunities presented by rapidly deregulating European markets. In 1997,
      according to industry sources, the European international long distance
      market for voice services was the largest in the world, with approximately
      35 billion minutes of use. According to industry sources, Europe's volume
      of international minutes grew approximately 12% from 1996 to 1997.
      Industry sources estimate the European wholesale and retail market for all
      Internet services was $1.9 billion in revenue for 1997.
 
    - LEVERAGE ESTABLISHED MARKET PRESENCE AND LOCAL DISTRIBUTION NETWORK. We
      established an early presence in Western Europe to capitalize on the
      opportunities presented by deregulation of the telecommunications
      industry. As a result, we gained substantial experience in the
      operational, technical, financial and logistical issues involved in
      operating a network and building a sales force in Western Europe. To date,
      we have established sales offices in twelve Western European cities and
      have established indirect sales offices, through arrangements with
      independent sales representatives and telemarketing agents, in more than
      180 locations in Western Europe. We believe that we are positioned to
      further capitalize on market opportunities in Western Europe.
 
    - FOCUS ON END USERS. We have established a customer base of small and
      medium-sized businesses to which we currently sell long distance voice
      services. The Circe Network allows us to provide high quality services to
      these end users at competitive prices, particularly businesses with
      multiple offices that require significant capacity. Carrier preselection,
      scheduled for the year 2000 in most countries in the European Union, will
      enable us to capture a larger portion of our customers' telecommunications
      spending.
 
    - LEVERAGE CIRCE NETWORK THROUGH RESELLERS AND CARRIERS. To efficiently use
      capacity on our network, we sell switched minutes to wholesale customers
      and other resellers. While we are constructing the Circe Network for our
      own use, we also intend to sell switched minutes and to opportunistically
      sell excess capacity on the network, thus enhancing the utilization of our
      switched network and reducing our construction cost.
 
    - OFFER A COMPREHENSIVE RANGE OF COMMUNICATION SERVICES. Historically, we
      have only offered voice and value-added services such as facsimile
      transmission. The Circe Network will significantly expand our ability to
      meet the growing demand for data services and to offer a comprehensive
      range of these services including Internet access and transmission, frame
      relay, asynchronous transfer mode and Internet protocol services, as well
      as private line and data center co-location services. All of these
      services are extremely capacity intensive, and the high cost of leased
      transmission capacity made it uneconomical to offer these services without
      owning our own network. See "Risk Factors--We May Not Be Able to Provide
      Data Transmission Services Effectively."
 
    - BECOME A LOW COST PROVIDER OF COMMUNICATIONS SERVICES. We believe that
      ownership of our network is critical to becoming a low-cost provider of
      bundled communications services. In addition, network ownership will
      enable us to manage service offerings and transmission quality. To achieve
      this objective, we (1) have invested in points of presence and switches,
      (2) are in the process of
 
                                       40
<PAGE>
      constructing the Circe Network, and (3) have purchased and swapped for
      capacity on fiber optic cable systems in and between Western Europe and
      the U.S.
 
    - PURSUE ACQUISITIONS, INVESTMENTS AND STRATEGIC ALLIANCES. In addition to
      systematically expanding through internal growth, in the future we intend
      to expand our services and network capabilities through acquisitions,
      investments and strategic alliances in order to lower termination costs
      and achieve desired economies of scale.
 
SERVICES
 
    We currently provide competitively priced long distance services with
value-added features that typically have not been provided by the respective
international telecommunications operator in many of the countries in which we
operate. The products and services include switched and dedicated long distance,
800 services, calling cards, domestic and international private line, debit
cards, conference calling, advanced billing systems, enhanced fax and data
connections and facilities management. We are actively exploring the provision
of new services, including Internet access, web hosting, asynchronous transfer
mode and frame relay services, the provision and management of intranets and
virtual private networks and video conferencing. We recently entered into an
arrangement with Lucent to facilitate the provision of these services in the
future.
 
    Our principal services include:
 
    VIADIRECT--a service permitting domestic and international calling to more
than 230 countries and territories through interconnect switched access. This
service is currently marketed exclusively in Belgium, France, Germany, The
Netherlands and the United Kingdom where we have full interconnection and a
national operator's license. In addition, carrier preselection, eliminating the
requirement to dial carrier selection codes, is available in Germany.
 
    VIADIRECT PLUS--provides dedicated access via a leased line from the
customer to Viatel's network, permitting calling without dialing access or
location codes.
 
    VIACALL EXPRESS--provides a paid (local) access or toll free number
programmed to dial an existing phone number or system, generally in another
country, without the need for special circuits or modifications.
 
    VIACALL--enables virtual private network calling to a pre-defined group of
locations within a closed user group that can be modified as required, subject
to regulatory limitations.
 
    VIACONNECT--provides "anywhere to anywhere" international callback access
through manual, automatic or Internet initiated callback. These services are
also offered with international toll-free access, subject to pricing
considerations.
 
    VIAGLOBE--provides calling card access from more than 50 countries. In
addition to offering savings over the calling cards of AT&T, MCI and other
providers of credit-based international calling cards, VIAGLOBE provides 24-hour
operator assistance and speed dialing.
 
    VIACARD--is a prepaid international debit card which provides many of the
same features as VIAGLOBE on a prepaid basis.
 
    VIALINK--is the new audio conference service, allowing automatic, manual or
operator assisted establishment of conference calls 24 hours a day, seven days a
week.
 
    VIA0800--a personal 0800 number permitting users to call the sponsor at no
cost.
 
                                       41
<PAGE>
DATA SERVICES
 
    The communications industry is expected to grow in data in the near term. To
efficiently handle this growth, the industry has been shifting away from circuit
switching, where a route is maintained for the duration of an entire call, to
packet switching, where digital packets of information for various destinations
are routed over a frame relay, asynchronous transfer mode or Internet protocol
network in an efficient and cost effective manner.
 
    As part of our strategy to capture a share of the rapidly growing data
business market, in the first quarter of 1999 we entered into an arrangement
with Lucent pursuant to which Lucent is installing asynchronous transfer mode
backbone network equipment on our Circe Network. This backbone equipment is
designed to enable us to provide packet switched voice, video conferencing,
private intranets and dedicated Internet protocol transport over an integrated
platform and offer end users high capacity, speed and reliability. Lucent has
agreed to cooperate with us in developing marketing strategies to promote our
data services, to train our personnel and to assist us in achieving
network-to-network interfaces with certain specified carriers. We believe that
our data network will be commercially operable in the fourth quarter of 1999.
 
    We have no direct experience in offering data services. See "Risk
Factors--We May Not Be Able to Provide Data Transmission Services Effectively."
 
THE VIATEL NETWORK
 
    We currently operate one of Europe's largest pan-European networks, with
international gateway switching centers in New York, New York, Somerset, New
Jersey and London, England, points of presence in 45 Western European cities,
including switches in Amsterdam (The Netherlands), Barcelona and Madrid (Spain),
Brussels (Belgium), Frankfurt (Germany), Milan and Rome (Italy) and Paris
(France), and our Circe Network which currently consists of 1,850 route
kilometers. Additional points of presence are placed to enhance network use and
as required by the various interconnection agreements to which we are a party.
We intend to install additional points of presence in cities with both
significant calling activity directed to our switched-based cities and
significant potential for originating and terminating international and domestic
long distance traffic.
 
    Access to our services is obtained either through "indirect access" or
"dedicated access." Currently, substantially all of our business end-users use
one or more forms of indirect access. Indirect access requires the end user to
use (1) carrier selection codes (e.g., "1623" in The Netherlands, Belgium and
France, "01079" in Germany), which requires us to pay a regulated tariff for
using the incumbent telecommunications operator's network to originate the
calls; (2) paid access, which requires the end user to pay another carrier to
access our services; (3) national or international toll-free, which accesses a
Viatel switch, by direct dial or (4) call reorigination, which enables the end
user to receive a return call providing a dial tone originated from one of our
U.S. switching centers. End users using dedicated access are connected to one of
our switches or points of presence by a private leased line connected to the end
user's premises. Carrier selection and dedicated access are our access methods
of choice. As the regulatory environment permits, we expect more customers will
pre-select us as their long distance provider. As our service offering broadens,
we anticipate the percentage of our customers who utilize dedicated access will
increase. We currently have interconnection agreements with Belgacom (Belgium),
British Telecom (United Kingdom), Deutsche Telekom (Germany), France Telecom
(France), KPN (The Netherlands) and Telecom Italia. We also have interconnection
agreements with Cable & Wireless (United Kingdom) and Infostrada (Italy). We are
currently negotiating an interconnection agreements with Telefonica de Espana
and SwissCom. We cannot assure you that we will be successful in securing such
interconnection agreements in a satisfactory or timely manner.
 
    Our ownership of transmission infrastructure and switches reduces our
reliance on other carriers, enables routing of telecommunications traffic over
multiple transmission paths, aids in controlling costs and permits the
compilation of call record data and other customer information.
 
                                       42
<PAGE>
    THE EUROPEAN PORTION OF OUR NETWORK
 
    Our network in Europe currently consists of an international gateway
switching center in London, switches in the Western European cities mentioned
above and our Circe Network. The cities in which our switches are located were
chosen due to the substantial number of international calls originating there.
To date, our European network has been primarily used for call origination. We
anticipate increasing use of our European network to transport calls in Western
Europe. See "--Carrier Contracts."
 
    CIRCE NETWORK
 
    Our Circe Network is a series of state-of-the-art, high quality, high
capacity, self-healing rings, utilizing advanced synchronous digital hierarchy,
the current international standard for digital transmission, and dense wave
division multiplexing technology.
 
    As currently planned, the Circe Network will be comprised of five
interlocking, bi-directional rings, consisting of approximately 8,700 route
kilometers of fiber optic cable. The first phase of the Circe Network,
consisting of approximately 1,850 route kilometers (including 312 route
kilometers of undersea fiber optic cable) was placed into operation during the
first half of March. The second phase, which will extend through northern
France, The Netherlands and into western Germany, is scheduled to be placed into
service during the third quarter of 1999. The third phase, which will extend
through eastern Germany, is scheduled to be placed into service during the first
quarter of 2000. We currently anticipate that the fourth and fifth phases of the
Circe Network, which will extend into southern France and Switzerland, will be
completed during the second quarter of 2000.
 
    The Circe Network offers incumbent telecommunications operators and new
entrants a compelling, cost-effective, high quality alternative for the
transport of European cross-border telecommunications traffic. Under the
traditional system of carrying cross-border telecommunications traffic in
Europe, the incumbent telecommunications operator did not develop end-to-end
cross-border circuits, but rather connected their national networks with other
carriers at the border. The Circe Network's cross-border transport will offer
consistently high transmission quality at reduced cost.
 
    Key characteristics of the Circe Network include:
 
    STATE-OF-THE-ART-TECHNOLOGY.  The Circe Network uses a laser-generated light
to transmit information bi-directionally over fiber optic glass strands with an
initial capacity of 20 gigabits per second. In addition, the Circe Network
employs dense wave division multiplexing technology. This technology allows more
discrete wavelengths of light to be transmitted through fiber, thereby
permitting the transfer of greater amounts of information at a lower cost than
was achievable with prior fiber optic technology.
 
    UNIFORM NETWORK ARCHITECTURE.  The entire Circe Network will consist of a
single uniform configuration of Nortel Telecom's optronics and Lucent's fiber
optic cable, thereby enhancing service quality while improving efficiency and
lowering costs.
 
    SECURE AND RELIABLE.  The Circe Network is being designed to provide high
security and reliability, employing such features as:
 
    - two redundant network operating centers monitoring the network 24 hours a
      day, seven days a week,
 
    - a self-healing architecture to allow for instantaneous restoration in the
      event of a single fiber cut,
 
    - fiber optic cable generally installed in high-density polyethylene
      conduits on terrestrial portions of the system, and
 
    - advanced cable armoring techniques on the submarine portions of the
      system.
 
    SCALABLE AND FLEXIBLE.  The Circe Network's high density network
architecture may be upgraded, without service interruptions, to at least 320
gigabits per second per fiber pair through the use of dense
 
                                       43
<PAGE>
wave division multiplexing technology, to support demand for bandwidth intensive
data applications. We anticipate that each ring of the Circe Network will
contain multiple conduits containing at least 48 fibers. These conduits will
have excess space through which additional fibers may be run without the
necessity for any further material civil works.
 
    PRIVATE LINE CIRCUITS
 
    While some of our nine switches in Western Europe are currently still
connected to our international gateway switching center in London by private
line circuits, these switches will be connected by the Circe Network as the
various rings are constructed and placed into commercial operation. Private line
circuits are permanent point-to-point connections for voice and data
transmissions and, when certain levels of volume are reached, are less expensive
for us than purchasing minutes of use on another carrier's network. The private
line circuits connecting our switches to the international gateway switching
center in London are leased directly, or indirectly through third parties, from
the incumbent telecommunications operator in the countries in which these calls
originate.
 
    DIGITAL FIBER OPTIC CABLE OWNERSHIP
 
    As part of our concerted effort to convert leased capacity to owned capacity
for the purpose of improving operating margins, we have continued to purchase
indefeasible rights-of-use or minimum investment units in digital fiber optic
cable systems, including indefeasible rights-of-use in (i) CANUS-1/CANTAT-3
(8.192 megabits per second), a transatlantic cable originating in the United
States, Canada and the United Kingdom, (ii) TAT-12/13 (8.192 megabits per
second), a transatlantic cable originating in the United States, the United
Kingdom and France, (iii) Atlantic Crossing-1 (1,088.5 megabits per second), a
transatlantic cable originating in the United States and the United Kingdom, and
(iv) Gemini (44.736 megabits per second), a transatlantic cable originating in
the United States and the United Kingdom, and minimum investment units in (i)
FLAG (2.048 megabits per second), a cable connecting Europe with multiple
locations in the Middle East and South and Eastern Asia, (ii) TAT-14 (311.0
megabits per second) and (iii) JUS-1 (155.5 megabits per second). We also intend
to acquire additional interests in digital fiber optic cable originating from
our owned infrastructure and connected to certain European Union member states
in which we have a physical presence. These cables will be used for transmission
of traffic between the United States and Europe and within Europe, resulting in
improved service quality at lower cost. By combining our international gateway
switching centers in New York and London with our transatlantic fiber optic
cable capacity, we believe that we will be able to provide customers with
improved quality, while lowering our transmission costs. See "Management's
Discussion and Analysis of Financial Condition and Results of Operations" for a
discussion of the effect of bringing traffic on-net.
 
    SWITCHING PLATFORMS
 
    Our entire network utilizes "intelligent switches" which incorporate
software designed to achieve least cost routing, the process by which we enhance
the routing of calls over the network for more than 230 countries and
territories. Least cost routing is designed to allow calls that are not routed
over our network to be routed directly from our switches to carriers that offer
call completion at the lowest rate for each particular route at any given time.
 
    Our network uses high capacity digital switching platforms designed to
provide services quickly and cost-effectively. The switches are modular and
scalable and incorporate some of the most advanced technologies such as
self-diagnosis, integrated services, digital network hierarchical, call control
and dynamic network management software. The backbone switches are primarily
Nortel Telecom DMS switches. As our network continues to evolve, the installed
base of switches can be augmented or upgraded to create a cost effective,
scalable network.
 
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    INTERNATIONAL NETWORK OPERATIONS CENTERS
 
    We currently monitor the activity of our network from international network
operations centers in Egham, England and Somerset, New Jersey. These
international network operations centers have been fitted with sophisticated
surveillance and control capability, fraud detection and real time transmission
quality enhancements. Our Omaha, Nebraska site houses back office systems
supporting the international network operations centers and our network. Each
international network operations center is capable of acting as a full backup to
the other and will allow full monitoring capability and remote diagnostics and
testing on key elements of our network.
 
    The international network operations centers will utilize a portfolio of
telecommunications network management operations support systems from Lucent.
The Lucent systems are expected to be functionally integrated into one platform
supporting multi-vendor network elements. Service activation provides workflow
management from order entry through network provisioning and into billing.
Service assurance includes trouble receipt, trouble management, and switch
surveillance to include both traffic management and fault monitoring. Network
management includes inventory management, design and network performance. The
Lucent operations support systems provide us with state-of-the-art service
activation, service assurance and network management capabilities.
 
SALES AND MARKETING; CUSTOMERS
 
    The Circe Network network is designed to allow end users, carriers and
resellers to integrate high quality, cross-border capacity into their end user
offerings. Prior to bringing the Circe Network into service, we were limited in
our ability to provide high capacity services to other carriers and, thus
focused our business on selling to end users and selling switched minutes to
carriers and resellers in order to help use the fixed capacity of leased lines.
With the high quality, low cost transmission capacity to be provided by the
Circe Network, we will be well positioned to offer large capacity services to
the additional market segments listed below. We are targeting the following
seven major market segments:
 
    - RESELLERS. Resellers are carriers that do not own transmission facilities
      but obtain communications services from another carrier for resale to the
      public. Resellers are a growing portion of the market and are expected to
      increase in conjunction with the liberalization of the European
      telecommunications market.
 
    - INCUMBENT TELECOMMUNICATIONS OPERATORS. These customers consist of the
      incumbent telecommunications operators that have historically employed
      bilateral agreements with other incumbents for cross-border connectivity
      but are now selling their own transborder connectivity by leasing capacity
      on alternative networks.
 
    - INTERNATIONAL CARRIERS. These customers consist of non-European carriers
      with traffic between European and other international gateways. We can
      provide these customers a pan-European distribution network to gather and
      deliver traffic to and from their own networks and other hubs.
 
    - END USERS. Small- to large-sized enterprises need inexpensive voice and
      data services. The Circe Network should allow us to satisfy this need and
      provide bundled services. We expect that additional demand for alternative
      service providers will come from increased usage of dedicated circuits for
      Internet access, private lines for the deployment of wide-area networks by
      large enterprises, "single source" local and long distance services by
      small and medium-sized enterprises and emerging high capacity applications
      like cable TV programming distribution (other than broadcast) to the end
      user.
 
                                       45
<PAGE>
    - ALTERNATIVE CARRIERS. These customers consist of new entrant carriers,
      cable TV and mobile carriers and competitive access providers. These new
      carriers have chosen to compete with the incumbent telecommunications
      operators in their respective countries.
 
    - INTERNET SERVICE PROVIDERS. Internet service providers are emerging
      rapidly and are expected to generate significant requirements for the
      services which we offer. As capacity becomes available in Europe, Internet
      usage also is expected to grow. These networks require large capacity
      international connectivity services between Internet nodes (points of
      interconnection among multiple local Internet service providers) in all
      local European markets.
 
    - VALUE ADDED NETWORKS AND OTHER SERVICE PROVIDERS. Value added networks are
      data communications systems in which special service features enhance the
      basic data transmission facilities offered to customers. Many of these
      networks are targeted to the data transfer requirements of specific
      international customer segments, such as financial institutions. Many
      value added networks' basic network transmission requirement is to connect
      data switches or processors. Value added networks' providers purchase
      their own international circuits and build additional resiliency into
      their network infrastructure. We will allow them to meet these needs
      cost-effectively, and to extend their services to new markets or customers
      while minimizing capital investment. This market segment is expected to
      experience substantial growth over the next several years.
 
    During 1998, one customer, LD Exchange.com, accounted for 10.6% of our
revenues.
 
    From 1991 to 1994, our sales and marketing efforts were conducted by
independent sales representatives in each of our markets. In late 1994, we began
establishing our own direct sales forces in certain Western European markets to
take greater control over the sales and marketing functions and to provide a
higher level of customer service. Currently, we have direct sales forces in
twelve cities in Western Europe and have established indirect sales offices,
through arrangements with independent sales representatives and telemarketing
agents, in more than 180 locations in Western Europe. We have sales
professionals dedicated to marketing and maintaining relationships with our
wholesale customers in the United States and in the United Kingdom. In Europe,
our sales and marketing staff is currently divided into two categories: direct
sales representatives and indirect sales representatives. Direct sales
representatives are responsible for face-to-face sales efforts to larger
accounts and indirect sales representatives are responsible for telesales to
smaller accounts.
 
    Our direct sales personnel are currently compensated on a salary and
commission basis, with potential commissions being paid on the basis of revenues
generated by new customers solely during their first three months as a customer.
After this three month period, the customer is turned over to pro-active account
managers who manage the account and are compensated based on the monthly growth
of such account above certain minimum requirements. We believe that this
compensation structure provides maximum incentive to our direct sales force to
continue to grow our customer base and revenue.
 
    Our independent sales representatives are retained on a
non-exclusive/commission-only basis, with commissions being subject to charge
back for revenues not collectible by us. We believe that our relationship with
our independent sale representatives is good.
 
INFORMATION SYSTEMS
 
    We believe that integrated and reliable billing and information systems are
key elements for growth and success in the telecommunications industry.
Accordingly, we have made significant investments to acquire and implement
sophisticated information systems which are designed to enable us to:
 
    - monitor and respond to customer needs by developing new and customized
      services;
 
    - manage least cost routing;
 
    - provide customized billing information;
 
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<PAGE>
    - provide high quality customer service;
 
    - detect and control fraud;
 
    - verify payables to suppliers; and
 
    - rapidly integrate new customers.
 
    We believe that our network intelligence, billing and financial reporting
systems enhance our ability to competitively meet the increasingly complex and
demanding requirements of the international and national long distance markets.
While we believe that these systems are currently sufficient for our operations,
these systems will require routine upgrades and ongoing investments.
 
    We currently have a turnaround time of approximately 48 hours for new
account entry, subject to credit approval. However, commencement of service can
take substantially longer. Our billing system provides multicurrency billing,
itemized call detail, city level detail for destination reporting and electronic
output for select accounts. Customers are provided with several payment options,
including automated credit card processing and automated direct debiting.
 
    We have developed software to provide telecommunications services and render
customer support. Each switch has a call detail recording function which is
designed to enable us to: (1) achieve accelerated collection of call records;
(2) detect fraud and unauthorized usage; and (3) permit rapid call detail record
analysis.
 
    We also use software to assist in analyzing traffic patterns and determining
network usage and busy hour percentage, originating traffic by switching center,
terminating traffic by supplier and originating traffic by customer. This data
is utilized to provide least cost routing, which may result in call traffic
being transmitted over our transmission facilities, other carriers' transmission
facilities or a combination of such facilities. If traffic cannot be handled
over the least cost route due to overflow, the least cost routing system is
designed to transmit the traffic over the next least cost route. The least cost
routing system chooses among the several variables to minimize the cost of a
long distance call over 15 different suppliers and multiple choices of
terminating carrier per country. The performance of the least cost routing
system is verified based on a daily overflow report generated by our network
traffic management and a weekly/ monthly average termination cost report
generated by our billing system.
 
CARRIER CONTRACTS
 
    We have entered into contracts to purchase switched minute capacity from
various domestic and foreign carriers and currently depend on such contracts for
origination and termination of traffic on our network as well as for resale of
this capacity to others. Carrier costs currently constitute a significant
portion of our variable costs. Pursuant to these contracts, we obtain guaranteed
rates, which are generally more favorable than otherwise would be available, by
committing to purchase minimum amounts of switched minutes from such carriers.
If we fail to meet our switched minute minimum requirements under a carrier
contract, we would still be required to pay our minimum monthly commitment as a
penalty. We do not believe that the loss of any one supplier or contract would
have a material adverse impact on our business, financial condition or results
of operations. See "Management's Discussion and Analysis of Financial Condition
and Results of Operations--Liquidity and Capital Resources."
 
COMPETITION
 
    Our competitors include the incumbent telecommunications operator in each
country in which we operate, global alliances among some of the world's largest
telecommunications carriers, such as British Telecom and AT&T, Global One
(Sprint, France Telecom and Deutsche Telekom) and the alliance between MCI
Worldcom and Telefonica de Espana, and new entrants, such as alternative
carriers, Internet backbone networks and other service providers. In addition
Colt Telecom Group and Level 3 Communications are sharing the costs of
constructing two networks--one to link the German cities of
 
                                       47
<PAGE>
Berlin, Koln, Dusseldorf, Frankfurt, Hamburg, Munich and Stuttgart and the other
linking Paris, Frankfurt, Amsterdam, Brussels and London. Other potential
competitors include:
 
    - cable communications companies,
 
    - wireless telephone companies,
 
    - electric and other utilities with rights-of-way,
 
    - railways,
 
    - microwave carriers, and
 
    - large end-users which have private networks.
 
    The intensity of competition and price declines in both billable minutes and
capacity sales has increased over the past several years and we believe that
this kind of competition and price declines will continue to intensify,
particularly in Western Europe, as other providers obtain connectivity. We are
aware that certain long distance carriers are expanding their capacity and
believe that other long distance carriers and data service providers, as well as
potential new entrants to the industry, are considering the construction of new
fiber optic and other long distance transmission networks. Since the cost of the
actual fiber is a relatively small portion of building new transmission lines,
persons building such lines are likely to install fiber that provides
substantially more transmission capacity than will be needed over the short or
medium term. Further, recent technological advances have shown the potential to
greatly expand the capacity of existing and new fiber optic cable. In addition,
our sales or leases of capacity on the Circe Network to other carriers may
result in competitors having capacity on our routes along the Circe Network,
which may in turn result in pricing pressures with respect to traffic carried
along these routes. If industry capacity expansion results in capacity that
exceeds overall demand in general or along any of our routes, severe additional
pricing pressure could develop. In addition, strategic alliances or similar
transactions could result in additional pricing pressure on long distance
carriers. Such pricing pressure could have a material adverse effect on us and
the value of our common stock. See "Management's Discussion and Analysis of
Financial Condition and Results of Operations--Overview."
 
    Many of our current and potential competitors have substantially greater
financial, marketing and other resources than we do. If our competitors devote
significant additional resources to the provision of international or national
long distance telecommunications services to our target customer base, this
action could have a material adverse effect on our business, financial
condition, results of operations and the price of our common stock and we cannot
assure you that we will be able to compete successfully.
 
    Because all of our current and intended European markets (other than the
United Kingdom) have only liberalized the provision of switched voice telephony
during the past year or still are in the process of liberalizing, customers in
most of the markets are not accustomed to obtaining services from competitors to
incumbent telecommunications operators and may be reluctant to use emerging
telecommunications providers such as us. In particular, our targeted customer
base may be reluctant to entrust their telecommunications needs to new operators
that are believed to be unproven. In addition, in continental Europe, certain of
our competitors (including the incumbent telecommunications operators) provide
potential customers with a broader range of services than we can offer.
 
    Competition for customers in the telecommunications industry is primarily
based on price and quality of services offered. We price our services primarily
by offering discounts to the prices charged by incumbent telecommunications
operators and other major competitors. However, prices for long distance calls
have decreased substantially over the past few years in the markets in which we
currently maintain operations and in which we expect to establish operations.
Some of our larger competitors may be able to use their greater financial
resources to cause severe price competition in the countries in which we operate
or expects to operate. Incumbent telecommunications operators in several Western
European countries are responding to deregulation far more rapidly and
aggressively than occurred after deregulation in the United States and the
United Kingdom. We expect that prices for our services will continue to decrease
for
 
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<PAGE>
the foreseeable future and that incumbent telecommunications operators and other
dominant carriers will continue to improve their product offerings.
 
    The improvement in product offering and customer service by the incumbent
telecommunications operators could have a material adverse effect on our
competitiveness to the extent that we are unable to provide similar levels of
offerings and services. If the incumbent telecommunications operator in any
jurisdiction uses its competitive advantages to their fullest extent, our
operations in that jurisdiction would be adversely affected. Furthermore, the
marginal cost of carrying calls over fiber optic cable is extremely low. As a
result, certain industry observers have predicted that, within a few years,
there may be dramatic and substantial price reductions and that long distance
calls will not be significantly more expensive than local calls. In addition,
numerous carriers currently offer or are implementing plans to offer
telecommunications services over the Internet at substantially reduced prices.
Any price competition could have a material adverse effect on our business,
financial condition, results of operations and result in a decrease in the price
of our common stock.
 
    Incumbent telecommunications operators generally have certain competitive
advantages that we and other competitors do not have due to their control over
local connections. We rely on the incumbent telecommunications operator for
access to the public switched telephone network and the provision of leased
lines, and the failure of the incumbent telecommunications operators to provide
this kind of access or leased lines at reasonable pricing or within a reasonable
time frame could have a material adverse effect on our business, financial
condition, results of operations and result in a decrease in the price of our
common stock. The reluctance of some national regulators to grant regulatory
approvals, provide operative interconnection and enforce access to these
operators' networks and essential facilities could have a material adverse
effect on our competitive position. We cannot assure you that we would be able
to compete effectively in any of our current or proposed markets. The Circe
Network will reduce our dependence on incumbent telecommunications operators for
leased long-haul lines, but it will not reduce our dependence on such carriers
to "last mile" access to the vast majority of our end user customers.
 
GOVERNMENT REGULATION
 
    OVERVIEW
 
    National and local laws and regulations governing the provision of
telecommunications services differ significantly among the countries in which we
currently operate and intend to operate. The interpretation and enforcement of
these laws and regulations varies and could limit our ability to provide certain
telecommunications services in certain markets. We cannot assure you that future
regulatory, judicial and legislative changes will not have a material adverse
effect on us, that domestic or international regulators or third parties will
not raise material issues with regard to our compliance with applicable laws and
regulations, or that other regulatory activities will not have a material
adverse effect on our business, financial condition, results of operations and
the price of our common stock.
 
    INTERNATIONAL TRAFFIC
 
    Under the WTO Agreement, concluded on February 15, 1997, 69 countries
comprising 95% of the global market for basic telecommunications services agreed
to permit competition from foreign carriers. In addition, 59 of these countries
have subscribed to specific procompetitive regulatory principles. The WTO
Agreement became effective on February 5, 1998 and has been implemented, to
varying degrees, by the signatory countries. We believe that the WTO Agreement
will increase opportunities for us and our competitors. However, we cannot
assure you that the WTO Agreement will result in beneficial regulatory
liberalization in all signatory countries.
 
    On November 26, 1997, the FCC adopted the Foreign Participation Order to
implement the U.S. obligations under the WTO Agreement. In this order, the FCC
adopted an open entry standard for carriers from WTO member countries, generally
facilitating market entry for such applicants by
 
                                       49
<PAGE>
eliminating certain existing tests. These tests remain in effect, however, for
carriers from non-World Trade Organization member countries.
 
    International carriers serving the United States, including us, are subject
to the FCC's international settlements policy. The international accounting rate
system allows a U.S. facilities-based carrier to negotiate an accounting rate
with a foreign carrier for handling each minute of international telephone
service. Each carrier's portion of the accounting rate, usually one-half, is
referred to as the settlement rate. Historically, international settlement rates
have vastly exceeded the cost of terminating telecommunications traffic. The
FCC's international settlements policy requires: (1) the equal division of the
accounting rate between the U.S. and foreign carrier; (2) nondiscriminatory
treatment of U.S. carriers, and (3) proportionate return of inbound traffic. To
enforce the international settlements policy, the FCC has required carriers to
file publicly available copies of their international settlement arrangements.
 
    The FCC adopted rules regarding specific rate levels for international
settlements rates, which became effective on January 1, 1998. International
Settlement Rates Order generally requires U.S. facilities-based carriers to
negotiate settlement rates with their foreign correspondent at no greater than
FCC-established benchmark prices. In addition, the International Settlement
Rates Order imposed new conditions upon certain carriers, including us. First,
the FCC conditioned facilities-based authorizations for service on a route on
which a carrier has a foreign affiliate upon the foreign affiliate offering all
other U.S. carriers a settlement rate at or below the relevant benchmark. Our
foreign affiliates satisfy this condition. Second, the FCC conditioned any
authorization to provide switched services over either facilities-based or
resold international private lines upon the condition that at least half of the
facilities-based international message telephone service traffic on the subject
route is settled at or below the relevant benchmark rate. This condition applies
whether or not the licensee has a foreign affiliate on the route in question.
 
    In the Foreign Participation Order described above, however, if the subject
route does not comply with the benchmark requirement, a carrier can demonstrate
that the foreign country provides "equivalent" resale opportunities.
Accordingly, since the February 9, 1998 effective date of the Foreign
Participation Order, we have been permitted to resell private lines for the
provision of switched services, also known as international simple resale, to
any country that either has been found by the FCC to comply with the benchmarks
or has been determined to be equivalent. We, however, remain subject to prior
FCC approval in order to provide resold private lines to any country in which we
have an affiliated carrier that has not been found by the FCC to lack market
power.
 
    Many parties have appealed the International Settlement Rates Order to the
U.S. Court of Appeals for the D.C. Circuit or have filed petitions for
reconsideration with the FCC. On January 12, 1999, the U.S. Court of Appeals for
the D.C. Circuit issued an order resolving this appeal, upholding the
International Settlement Rates Order in all respects. The appealing parties now
have until June 9, 1999 to exercise the option of requesting that the case be
heard by the U.S. Supreme Court. The petition for reconsideration is still
pending at the FCC. We cannot predict the outcome of these proceedings and their
possible impact on us or the price of the common stock.
 
    In new rules released on May 6, 1999, but not yet effective, the FCC has
removed the international settlements policy for: (1) all settlement
arrangements between U.S. carriers and foreign carriers that lack market power;
and (2) all settlement arrangements on routes where U.S. carriers are able to
terminate at least 50 percent of their traffic in the foreign market at rates
that are at least 25 percent below the applicable benchmark settlement rate. In
this international settlement policy order, the FCC also eliminated the
requirement that carriers file the settlement arrangements where the
international settlements policy has been eliminated. Finally, the international
settlement policy order expanded its rules to permit carriers to provide
international simple resale on any route where the resale carrier exchanges
switched traffic with a foreign carrier that lacks market power. Accordingly,
upon the effectiveness of these new rules, we will have more flexibility in
negotiating settlement arrangements with many carriers on many
 
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<PAGE>
routes, which we expect will lower our costs of terminating international
traffic, although our competitors will benefit from these new rules in the same
way.
 
    Increasing regulatory liberalization in many countries' telecommunications
markets now permits more flexibility in the way we can route calls. Although
certain FCC rules limit the way in which some international calls can be routed,
we do not believe that our network configuration, specifically the way in which
traffic is routed through our facilities in the U.K., is specifically prohibited
by, or undermines in any way the intent of, these rules. It is possible,
however, that the FCC could find that our network configuration violates these
rules. If we were found to be in violation of these routing restrictions, and if
the violation were sufficiently severe, it is possible that the FCC could impose
sanctions and penalties upon us.
 
    REGULATORY STATUS
 
    A summary discussion of the regulatory situations in certain geographic
regions in which we operate or have targeted for penetration is set forth below.
 
    EUROPEAN UNION.  The European Union consists of the following member states:
Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy,
Luxembourg, The Netherlands, Portugal, Spain, Sweden and the United Kingdom. The
European Union was established by the Treaty of Rome and subsequent treaties.
European Union member states are required to implement directives issued by the
European Commission and the European Council by passing national legislation. If
a European Union member state fails to effect such directives with national (or,
as the case may be, regional, community or local) legislation and/or fails to
render the provisions of such directives effective within its territory, the
European Commission may take action against the European Union member state,
including in proceedings before the European Court of Justice, to enforce the
directives. Private parties may also bring actions against European Union member
states for failures to implement such legislation.
 
    In an effort to promote competition and efficiency in the European Union
telecommunications market, the European Commission and European Council have
issued a number of key directives establishing basic principles for the
liberalization of the European Union telecommunications market. The general
framework for this liberalized environment has been set out in the European
Commission's Services Directive (the "Services Directive") and its subsequent
amendments, including, in particular, the Full Competition Directive, adopted in
March 1996 (the "Full Competition Directive"). These directives require most
European Union member states to permit competition in all telecommunications
services and had set January 1, 1998 as the date by which all restrictions on
the provision of telecommunications services and telecommunications
infrastructure were to be removed. These directives have been supplemented by
various harmonizing directives, which include the Open Network Provision
Directives, as well as two additional directives adopted in 1997, the Licensing
Directive and the Interconnection Directive.
 
    The Licensing Directive established a framework for the granting of national
authorizations and licenses related to telecommunications services. It permits
European Union member states to establish different categories of licenses for
providers of infrastructure and services, but requires the overall scheme to be
transparent and non-discriminatory. The Interconnection Directive requires
member states to remove restrictions preventing negotiation of interconnection
agreements, ensure that interconnection requirements are non-discriminatory and
transparent and to ensure adequate and efficient interconnection for public
telecommunications networks and publicly available telecommunications services.
 
    In October 1997, the European Commission issued a consultative document
supporting the implementation of long run incremental cost principles as a basis
for interconnection pricing. This document also sets forth interconnection
pricing benchmarks reflecting current interconnection agreements in European
Union member states. The European Commission believes such benchmarks
 
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<PAGE>
should be relied upon pending the adoption of accounting systems and
interconnection rates based on long run incremental cost principles.
 
    Several European Union member states have chosen to apply the provisions of
the Interconnection Directive within their jurisdictions in such ways as to give
more favorable treatment to infrastructure providers and network operators than
to carriers and resellers that have made no infrastructure investment. Such
distinctions must be objectively justified on the grounds of the type of
interconnection provided or because of relevant licensing conditions. The
Licensing Directive does not provide a clear definition of an infrastructure
investment, and many European Union member states have adopted inconsistent
approaches with respect to the level and type of infrastructure investment
required to justify differences in interconnection charges. While we believe
that the European Commission will seek to minimize these disparities in national
interconnection policies, there can be no assurance that these disparities can
be eliminated or significantly reduced or that any such differences in
regulatory treatment will not have a material adverse effect on us. To the
extent incumbent telecommunications operators deny or delay granting us
interconnection, even if only for a limited period of time, in any of the
countries in which we have or will have points of presence, we will be forced to
terminate traffic through refile or resale agreements with other carriers,
resulting in higher costs.
 
    Each European Union member state in which we currently conduct our business
has a different regulatory regime and such differences are expected to continue.
The requirements for us to obtain necessary approvals vary considerably from
country to country.
 
    BELGIUM.  In December 1997, the Belgian Federal Parliament provided for full
liberalization of the provision of telecommunications services. However, this
law and secondary legislation are not yet complete.
 
    Under the existing licensing scheme, applicants seeking a network operator
license must commit to invest 400 million Belgian Francs or to deploy 500
kilometers of transmission infrastructure within three years of the date the
license is granted as well as investing an amount equal to 1% of annual turnover
in order to fund research and development and other initiatives. Notwithstanding
these stringent requirements (which may be modified by European Commission
intervention that has been formally commenced), we obtained a license under the
provisional licensing system for the establishment and operation of a public
telecommunications network on June 30, 1998 and a provisional license for the
provision of voice telephony on July 3, 1998. Recently, these provisional
licenses were converted into definitive licenses.
 
    Belgium is one of the European Union member states which differentiates
between interconnection for infrastructure providers and network operators and
switch-based carriers and resellers. The interconnection tariffs of Belgacom
(Belgium's incumbent telecommunications operator), which have been officially
approved by the Belgian Institute for Postal Services and Telecommunications,
provides more favorable interconnection rates for infrastructure providers and
network operators than for switch-based carriers and resellers. As a result of
the construction of the Circe Network, we qualify for these more favorable
rates.
 
    The modified Belgian Telecommunications Law also provides for the creation
of a Universal Service Fund, to be managed by the Belgian Institute for Postal
Services and Telecommunications, to which operators may be required to
contribute funds in proportion to their revenues from the Belgian
telecommunications market. However, the Universal Service Fund system will not
be activated before the year 2000, and then only insofar as: (i) Belgacom claims
a compensation for being the universal service provider, (ii) the Belgian
Institute for Postal Services and Telecommunications considers that universal
service provision represents a net cost, and (iii) the Belgian Federal
Government takes a formal decision to activate the Universal Service Fund. From
1998 onwards, the Belgian Institute for Postal Services and Telecommunications
will "dry-run" the universal service costing model and keep operators informed
of the contributions that they may be required to make if and when the Universal
Service Fund is activated.
 
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<PAGE>
    FRANCE.  In July 1996, legislation was enacted providing for the
liberalization of all telecommunications activities in France by January 1,
1998.
 
    The establishment and operation of public telecommunications networks and
the provision of voice telephony services to the public are subject to
individual licenses granted by the Minister in charge of telecommunications upon
recommendation of France's new independent regulatory authority, the Authorite
de Regulation des T elecommunications ("ART").
 
    In December 1997, we filed a joint application for a license as a public
telecommunications network operator (under Article L33.1 of the French Code de
Postes et T elecommunications) and provider of voice telephony services to the
public (under Article L34.1 of the French Code de Postes et
T elecommunications). The license application was approved by both ART and the
relevant Minister during 1998. In March 1999, we obtained interconnection
arrangements which allow customers in the greater Paris region to originate and
terminate calls throughout France and all countries serviced by us. Additional
interconnections to the Strasbourg and Amiens regions are expected to be
obtained in mid-1999.
 
    We are subject to certain obligations in the operation of our public
telecommunications network, most notably in terms of non-discriminatory
treatment of customers and an obligation to accept reasonable requests for
interconnection from other carriers.
 
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<PAGE>
    France is also one of the European Union member states which differentiates
between interconnection for public telecommunications network operators, holding
a L33.1 license, and voice telephony service providers, holding a L34.1 license.
The interconnection tariffs of France Telecom, which have been officially
approved by ART, provide substantially more favorable interconnection rates for
public telecommunications network operators than for voice telephony service
providers.
 
    GERMANY.  The German Telecommunications Act of July 25, 1996 provided for
the liberalization of all telecommunications activities by January 1, 1998. The
German Telecommunications Act has been supplemented by several ordinances
concerning, among other things, license fees, rate regulation, interconnection,
universal service, frequencies and customer protection. The German
telecommunications sector is currently overseen by a new Regulatory Authority
for Telecommunications and Post ("RegTP") that operates under the supervision of
the Ministry of Economics and has taken over the regulatory responsibilities of
the disbanded Ministry of Post and Telecommunications.
 
    Under the German regulatory structure, licenses can be issued for different
types of infrastructure as well as for the provision of services based on
transmission lines provided by other service providers. Viatel has been issued a
nationwide class 3 infrastructure license and a nationwide class 4 license for
the provision of voice telephony.
 
    All existing interconnection agreements with Deutsche Telekom have been
terminated effective December 31, 1999, requiring all affected parties to seek
new interconnection with Deutsche Telekom. In a letter dated February 19, 1999,
the FCC expressed its concerns about the new interconnection regime and argued
that the action taken by Deutsche Telekom as well as other actions taken by such
carrier were designed to impede effective and competitive market entry. Although
Viatel believes that it will be able to obtain a new interconnection agreement
with Deutsche Telekom prior to December 31, 1999, we cannot provide any
assurance that this will be the case or that the interconnection arrangement
obtained will contain terms which are as favorable to us as those contained in
our current interconnection arrangement.
 
    ITALY.  In 1997, the Italian authorities enacted a legislative framework for
the full liberalization of telecommunications services by January 1, 1998. On
February 12, 1999, we received a license to provide voice telephony as well as
to own and operate infrastructure.
 
    On July 24, 1998, Telecom Italia published its Reference Interconnect Offer,
which has been amended recently due to decisions by the Italian regulator. The
offer allows interconnection at one point of interconnect and has brought
interconnection rates down to a level much closer to the European Union
benchmarks. We initiated interconnection negotiations towards the end of 1998
and obtained an interconnection agreement with Telecom Italia on April 30, 1999.
 
    In Italy, providers of network infrastructure and switched voice services as
well as national mobile operators must contribute to a universal service fund.
Such a requirement is to take effect in 1999 provided that Telecom Italia
demonstrates by March 31, 1999, on the basis of audited reports, that its
universal service obligations impose on it net losses. Even in these
circumstances, the Italian regulator can exempt new entrants from an obligation
to contribute to such a universal service fund. Both the Italian competition
agency and the European Commission are likely to recommend such an exemption
scheme to the Italian regulator. However, we cannot assess at this time any
possible impact of any such universal service obligations on its operating
margins.
 
    THE NETHERLANDS.  In the Netherlands the incumbent telecommunications
operation's monopoly regarding voice telephony was abolished effective July 1,
1997. Other community liberalization obligations, which took effect on December
15, 1998, were implemented through the new Netherland's Communications Act. With
the exception of radio frequencies, all licensing requirements have been
abolished by mandatory registration requirements with the Independent Post and
Telecommunications Authority. In February 1999, Viatel obtained from the
Independent Post and Telecommunications
 
                                       54
<PAGE>
Authority registrations to provide a public telecommunication service and to
install and provide a public telecommunications network.
 
    SPAIN.  The Spanish government implemented the full liberalization of public
switched telephone services on December 1, 1998. Viatel was granted a nationwide
infrastructure and voice telephony license in March 1999. We expect to sign an
interconnection agreement with Telefonica de Espana in the fourth quarter of
1999.
 
    SWITZERLAND.  A new Telecommunications Act was adopted by the Swiss
Parliament in April 1997 and came into effect on January 1, 1998, together with
certain ordinances containing more detailed regulations covering
telecommunications services, frequency management, numbering, terminal equipment
and license fees. The new Telecommunications Act provides for liberalization of
the Swiss telecommunications market as of January 1, 1998.
 
    The Swiss telecommunications regulatory framework facilitates market entry
by: (i) applying a notification procedure for resellers, (ii) applying a
procedure for operators wishing to be granted a concession for the establishment
and operation of transmission facilities and (iii) providing rights-of-way,
subject to a procedure of authorization, over the public domain to
facilities-based carriers. Pro-competitive regulation is also applicable in the
area of numbering.
 
    We have notified our activities as a provider of voice telephony services in
Switzerland but have not yet completed negotiation of an interconnection
agreement (in accordance with the notification procedure). We are applying for a
concession as a facilities-based carrier.
 
    Switzerland is not a member of the European Union and, accordingly,
directives do not apply. Switzerland is, however, a party to the WTO Agreement.
 
    UNITED KINGDOM.  The Telecommunications Act 1984 (the "U.K. Act") provides a
licensing and regulatory framework for telecommunications activities in the
United Kingdom. The U.K. has liberalized its market substantially to meet the
requirements of the Full Competition Directive. There is pending secondary
legislation to fully implement the European Commission Directives which may
affect the licenses which have been granted to Viatel and its competitors.
Viatel cannot predict what effect, if any, this legislation will have on its
business.
 
    Viatel UK has been granted an international simple voice resale standard
license and was awarded an international facilities license with code powers in
June 1998. In addition, Viatel UK has interconnection agreements with Cable &
Wireless and British Telecom.
 
    OTHER EUROPEAN MARKETS.  Our ability to expand in other countries will be
affected by the degree to which liberalization has been implemented in that
country. If for strategic reasons we decide to build out infrastructure in each
particular market prior to full liberalization and liberalization is delayed or
not fully implemented, we could sustain a loss on our infrastructure investment.
 
    LATIN AMERICA AND THE PACIFIC RIM.  Outside of the European Union, we
provide our customers with access to our services through the use of call
reorigination. A substantial number of countries have prohibited certain forms
of call reorigination. There can be no assurance that certain of our services
and transmission methods will not be or will not become prohibited in certain
jurisdictions.
 
    We are subject to a different regulatory regime in each country in Latin
America and the Pacific Rim in which we conduct business. Local regulations
determine issues significant to our business, including whether we can obtain
authorization to offer transmission of voice and voice band data directly or
through call reorigination. In general, competition is restricted in the region,
with the result that our ability to offer such service is limited. Regulations
governing enhanced services (such as facsimile and voice mail and data
transmission) tend to be more permissive than those covering voice telephony.
 
                                       55
<PAGE>
    ARGENTINA.  The telecommunications industry in Argentina was privatized in
1990, but opportunities for competitive entry in basic telephony services remain
restricted. The companies created at the time of privatization, Telecom and
Telefonica, respectively, were granted exclusive rights until 1997 to the
provision of domestic local and long distance fixed telephone service in the
northern and southern portions of Argentina, respectively. Telintar, a company
owned equally by Telecom and Telefonica, was given exclusive rights until 1997
for the provision of international telephony and data transmission services.
 
    Value-added services may be competitively provided and are essentially
deregulated. Although a license must be obtained, such licenses are routinely
granted. Facilities for international value-added services must be obtained from
Telintar. Currently, call reorigination is legal in Argentina, although the
established carriers have advocated strenuously against it and the government's
view has changed from time to time. Telecom and Telefonica have instituted
significant rate rebalancing measures which are likely to lessen the
attractiveness of call reorigination. The Supreme Court ruled in favor of rate
rebalancing, rejecting several challenges to it.
 
    We have had a sales representative in Argentina since 1991 who has focused
on call reorigination, Internet-initiated international business-to-business
service and international calling card services. We do not currently hold any
licenses in Argentina.
 
    BRAZIL.  In Brazil, value-added services are not considered to be
telecommunications services and currently can be provided on a completely
unregulated basis, without the necessity of obtaining a permit or a concession.
However, the service provider must operate through a Brazilian company. Call
reorigination is not prohibited in Brazil. A foreign ownership limit of 49% is
imposed under the 1996 "Minimal Law" for B-Band cellular, satellite and cable TV
services. There are presently no foreign ownership limits for limited services,
including specialized limited services, or value added services. Under the 1997
"General Telecommunications Law," the President retains the authority to impose
foreign ownership limits on other services, but by decree dated May 15, 1998,
the President expressly decided not to impose any such limits.
 
    Our services in Brazil currently include call reorigination and
international calling cards and fax store and forward which are classified as
value added-services and therefore do not require a license. We plan to offer
such services as well as to apply for licenses to offer specialized limited
services, which include private line and data transmission services.
 
    COLOMBIA.  Under a new Constitution adopted in 1991, the possibility of
private provision of public services was ratified in Colombia. This paved the
way for both privatization of the state-owned long distance company, TELECOM, as
well as the competitive entry of other entities. Specific plans for the
privatization of TELECOM have faltered due to, among other things, labor union
resistance. However, the government mandated that competition be introduced in
1998. Two competitors to TELECOM have been licensed. A federal judicial body
with jurisdiction over public contracts has recently issued a writ declaring
that the issuance of licenses for any additional competition in long distance
services must be authorized by new legislation. The implications of this
decision for us are not clear.
 
    In Colombia, there are in excess of 35 local operating companies, many
municipally owned. Under Colombian law, local service has been completely
deregulated and may be provided without a telecommunications concession or
license. Other telecommunications services require a concession or other
authorization.
 
    Value-added services are competitive, but must be licensed. There is
currently intense competition for value-added services, and the market for data
communications is one of the most dynamic segments of the telecommunications
sector. Although Colombian law requires that all telecommunications services be
rendered by Colombian entities, foreign investment is not limited.
 
    Most of our customers in Colombia access our network via international toll
free numbers. We have formed a Colombian subsidiary and have been awarded a
value-added services license. We are working on the establishment and operation
of a network to utilize the value-added services license.
 
                                       56
<PAGE>
    VENEZUELA.  Pursuant to the Telecommunications Law of 1940, all
telecommunications activities in Venezuela are reserved to the government,
although concessions or permits for the provision of such services may be
granted to third parties. The administration, inspection and monitoring of all
communications systems in Venezuela are carried out by the Ministry of
Transportation and Communications through the Comision Nacional de
Telecommunicaciones.
 
    The national telephone company of Venezuela, Compania Anonima Nacional de
Telefonos de Venezuela, was privatized in 1991 and its concession grants a
monopoly in the provision of basic telecommunications services until the year
2000. The only exceptions to this exclusivity are recently awarded concessions
for the provision of basic services to rural areas not reached by Compania
Anonima Nacional de Telefonos de Venezuela.
 
    Other telecommunications services, such as cellular telephony and other
mobile radio services, private telecommunications networks, switched data
networks and value-added services (including e-mail, Internet, video text,
telenext, voicemail and faxmail) are open to competition upon receipt of a
concession or permit, as applicable. Call reorigination is officially illegal in
Venezuela. The prohibition is supposed to be enforced by Comision Nacional de
Telecommunicaciones with the unofficial aid of Compania Anonima Nacional de
Telefonos de Venezuela through termination of subscriber service, but in
practice the prohibition is widely evaded.
 
    We do not have a local affiliate in Venezuela and do not hold any Venezuelan
concessions or authorizations. At present, our agents in Argentina offer only
Internet-initiated international business-to-business services and international
calling cards in Venezuela. We do not believe that these services are
encompassed within the prohibition against call reorigination, but it is
possible that Venezuelan authorities may consider them to raise similar policy
issues to prohibited call reorigination services. If the call reorigination
prohibition is deemed to apply, we may have to discontinue Internet-initiated
services in Venezuela.
 
    UNITED STATES.  Our provision of international service to, from and through
the United States generally is subject to regulation by the FCC. Section 214 of
the Communications Act requires a company to make application to, and receive
authorization from, the FCC to provide such international telecommunications
services. In May 1994, the FCC authorized us pursuant to Section 214 of the
Communications Act to resell public switched telecommunications services of
other United States carriers (the "Section 214 Switched Authorization"). The
Section 214 Switched Authorization requires that services be provided in a
manner that is consistent with the laws of countries in which we operate. We
also have a license to resell international private lines for the provision of
switched services between the United States and the United Kingdom and between
the United States and Canada. Additionally, in September 1996 we received final
approval for another Section 214 authorization from the FCC to provide both
facilities-based services and resale services (including both the resale of
switched services and the resale of private lines for the provision of switched
services) to all permissible international points. Finally, in September 1996 we
also received final approval for another Section 214 authorization from the FCC
to provide facilities-based service between the United States and the United
Kingdom over the CANUS-1 and CANTAT-3 cable systems (the "Section 214 UK
Facilities Authorization").
 
EMPLOYEES
 
    As of March 31, 1999, we had 575 full-time employees, approximately 273 of
whom were engaged in sales, marketing and customer service. None of our
employees is covered by a collective bargaining agreement. Management believes
that our relationship with our employees is good.
 
PROPERTIES
 
    Our tangible assets include a substantial investment in telecommunications
equipment. Our network and its component assets are the principal properties we
own. We own a significant portion of the
 
                                       57
<PAGE>
telecommunications equipment required for our business. Our network includes
installed fiber optic cable consisting of lighted (used) and dark (not used)
fibers, which is either owned or leased and is laid pursuant to various rights
of way. Other fixed assets are located at various locations in our service
areas.
 
    We currently occupy two sites in New York City, one of which serves as our
principal executive office, while the other is one of our international gateway
switching center. We also lease office space in Somerset, New Jersey, which
serves as our U.S. Network Operations Center, and Omaha, Nebraska, where our
billing and operations center is located. We lease locations pursuant to the
terms of the respective leases which expire at different times varying from May
2004 to March 2009.
 
    We have European sales offices in the following locations: London, England;
Paris, France; Brussels, Belgium; Amsterdam, The Netherlands; Frankfurt, Berlin,
Munich and Dusseldorf, Germany; Milan and Rome, Italy; and Barcelona and Madrid,
Spain; all of which are leased. The lease terms for our sales offices range from
5 years to 25 years. We also maintain switching sites in several countries
throughout Europe. In general, these locations are leased for a minimum term of
20 years, including renewal options.
 
LEGAL PROCEEDINGS
 
    We are involved from time to time in litigation incidental to the conduct of
our business. We believe that any potential adverse determination in any pending
action will not have a material adverse effect on our business, financial
condition or results of operations.
 
                                       58
<PAGE>
                                   MANAGEMENT
 
DIRECTORS AND EXECUTIVE OFFICERS
 
    The following table sets forth certain information with respect to the
directors and executive officers of Viatel as of May 19, 1999.
 
<TABLE>
<CAPTION>
NAME                                                      AGE                           POSITION
- -----------------------------------------------------     ---     -----------------------------------------------------
<S>                                                    <C>        <C>
Michael J. Mahoney(1)(2).............................         40  Chairman of the Board, Chief Executive Officer and
                                                                    President
Allan L. Shaw........................................         35  Senior Vice President, Finance; Chief Financial
                                                                    Officer and Director
Lawrence G. Malone...................................         47  Senior Vice President, Global Sales and Marketing
Sheldon M. Goldman...................................         39  Senior Vice President, Business Affairs; General
                                                                    Counsel and Secretary
Francis J. Mount.....................................         57  Senior Vice President, Engineering and Network
                                                                    Operations and Director
John G. Graham(1)(2)(3)..............................         60  Director
Paul G. Pizzani(1)(2)(3).............................         39  Director
</TABLE>
 
- ------------------------
 
(1) Member of the Directors Committee.
 
(2) Member of the Compensation Committee.
 
(3) Member of the Audit Committee.
 
    MICHAEL J. MAHONEY.  Mr. Mahoney has served as Chairman of the Board of
Viatel since September 1998, as its Chief Executive Officer since September
1997, as its President since September 1996 and as a director since 1995. Mr.
Mahoney was also Chief Operating Officer of Viatel from September 1996 to
September 1997, Executive Vice President, Operations and Technology of Viatel
from July 1994 to September 1996 and Managing Director, Intercontinental of
Viatel from January 1996 to September 1996. From August 1990 to June 1994, Mr.
Mahoney was employed by SITEL Corporation, a teleservices company, most recently
as President, Information Services Group. From August 1987 to August 1990, Mr.
Mahoney was employed by URIX Corporation, a manufacturer of telecommunications
hardware and software, in a variety of sales and marketing positions.
 
    ALLAN L. SHAW.  Mr. Shaw has served as Senior Vice President, Finance of
Viatel since December 1997 and as its Chief Financial Officer since January
1996. Mr. Shaw has served as a director of Viatel since June 1996. Mr. Shaw was
Vice President, Finance of Viatel from January 1996 to December 1997 and
Treasurer of Viatel from September 1996 to April 1998. Prior to becoming Vice
President, Finance and Chief Financial Officer, Mr. Shaw served as Corporate
Controller from November 1994 to December 1995. From August 1987 to November
1994, Mr. Shaw was employed by Deloitte & Touche LLP, most recently as a
Manager. Mr. Shaw is a Certified Public Accountant and a member of the American
Institute, United Kingdom Society and New York State Society of Certified Public
Accountants.
 
    LAWRENCE G. MALONE.  Mr. Malone has served as Senior Vice President, Global
Sales and Marketing of Viatel since May 1997. Mr. Malone served as Vice
President and Managing Director, Intercontinental of Viatel from September 1996
to May 1997 and served as its Vice President of Sales for Carriers/Wholesale
from January 1995 to September 1996. From December 1993 to December 1994, Mr.
Malone was employed by Frame Relay Technologies, a communications equipment
manufacturer, as Director of Sales. From December 1987 to November 1993, Mr.
Malone was employed by Republic Telcom Systems, a voice/ data networking
company, where he most recently served as Vice President of Sales and Marketing.
 
                                       59
<PAGE>
    SHELDON M. GOLDMAN.  Mr. Goldman has served as Senior Vice President,
Business Affairs and General Counsel of Viatel since December 1997. Prior to
becoming Senior Vice President, Business Affairs and General Counsel of Viatel,
Mr. Goldman served as Vice President, Business and Legal Affairs from December
1996 to December 1997 and served as United States General Counsel of Viatel from
April 1996 to December 1996. From January 1987 to March 1996, Mr. Goldman was
associated with the law firm of Wien, Malkin & Bettex. Since March 1996, Mr.
Goldman has been Of Counsel to the law firm of Brief Kesselman Knapp & Schulman,
LLP.
 
    FRANCIS J. MOUNT.  Mr. Mount has served as Senior Vice President,
Engineering and Network Operations of Viatel since December 1997 and as a
Director of the company since June 1998. Prior to joining the company, Mr. Mount
was Senior Vice President, Business Initiatives of Primus Telecommunications
Group from October 1997 to December 1997, responsible for Internet telephony,
European operations and network quality. From June 1996 to October 1997, Mr.
Mount was Executive Vice President and Chief Operating Officer of Telepassport,
Inc. and was Vice President and Chief Operating Officer of Telepassport, Inc.
from January 1996 to June 1997. From 1990 to January 1996, Mr. Mount was
employed by MCI, most recently as Director, Global Technical Services,
responsible for international development, alliance management and all technical
operations and services outside the United States, including the construction
and maintenance of large networks such as Hyperstream, "Concert" and private
networks for large accounts such as J.P. Morgan, Proctor and Gamble and I.B.M.
From March 1967 to December 1989, Mr. Mount was employed by AT&T in various
positions.
 
    JOHN G. GRAHAM.  Mr. Graham has served as a director of Viatel since June
1998. Mr. Graham has been the President and Chief Operating Officer of Utilities
Mutual Insurance Company since May 1, 1999, a position he assumed following his
retirement from GPU Service, Inc. From December 1998 to May 1999, Mr. Graham was
an Executive Vice President of GPU Service, Inc. and from 1987 to December 1998,
was Senior Vice President and Chief Financial Officer of GPU, Inc., a domestic
and international electric utility and independent power generation company. Mr
Graham was employed by GPU in various other capacities from 1976 to 1987. From
1970 to 1976, Mr. Graham was a Partner in the law firm of Ruprecht and Graham,
Newark, New Jersey. From 1993 to 1997, Mr. Graham served as a Director and
Chairman of the Audit Committee of Edisto Resources, Inc., which was engaged in
the exploration, production and marketing of natural gas and oil.
 
    PAUL G. PIZZANI.  Mr. Pizzani has served as a director of Viatel since April
1996. Mr. Pizzani is currently a partner at eVentures LLC. From November 1997 to
March 1999, Mr. Pizzani served as a Managing Director of Wasserstein Perella
Emerging Markets L.P. where he has been employed since November 1997. Prior to
November 1997, Mr. Pizzani was associated with COMSAT Corporation and its
subsidiaries in various capacities from November 1985 to October 1997, most
recently as Treasurer.
 
SENIOR MANAGEMENT
 
    GLENN K. DAVIDSON.  Mr. Davidson has served as Vice President, Corporate
Communications of Viatel since August 1998. Prior to joining the company, Mr.
Davidson was employed by the Computer & Communications Industry Association as
Executive Vice President, Chief Operating Officer and Corporate Secretary from
September 1995 to July 1998. From November 1994 to September 1995, Mr. Davidson
was an independent consultant. From May 1994 to November 1994, Mr. Davidson was
the Campaign Manager for Douglas Wilder's bid for election to the United States
Senate. From August 1991 to January 1994, Mr. Davidson was employed by the
Office of Governor, Commonwealth of Virginia, most recently as Chief of Staff.
From January 1990 to August 1991, Mr. Davidson was the Director of the Virginia
Liaison Office, Commonwealth of Virginia. From 1985 to 1990, Mr. Davidson was
employed by Computer & Communications Industry Association in various
capacities, most recently as Vice President and Chief of Staff.
 
                                       60
<PAGE>
    CHARLES T. FIELD.  Mr. Field has served as Vice President and Treasurer of
Viatel since September 1998. Prior to becoming Vice President and Treasurer, Mr.
Field served as Treasurer from April 1998 to September 1998. Prior to joining
Viatel, Mr. Field was employed by Horsehead Industries, Inc., a diversified
manufacturing company, from August 1995 to April 1998. From October 1987 to
August 1995, Mr. Field was employed by Deloitte & Touche LLP, Independent
Certified Public Accountants, most recently as Manager. Mr. Field is a Certified
Public Accountant and a member of the American Institute, United Kingdom Society
and Illinois Society of Certified Public Accountants.
 
    DEREK FOXWELL.  Mr. Foxwell has served as Viatel's Vice President of
Infrastructure Programs since January 1999. Prior to becoming Vice President of
Infrastructure Programs, Mr. Foxwell served as Director of Infrastructure
Programs from May 1998 to January 1999. From December 1997 to May 1998, Mr.
Foxwell served as a consultant to Viatel providing advice to the company in
connection with the development of the Circe Network. Prior to joining Viatel as
a consultant, Mr. Foxwell was a consultant to Nynex Network Service (Flag Ltd.)
where he chaired the Flag Assignment, Routing & Restoration Subcommittee and
Sprint International (PTAT) and acted as the operations and maintenance manager
for PTAT systems. From 1972 to 1991, Mr. Foxwell was employed by British
Telecom, most recently as Transmission Engineering Planning Manager,
International Cable Network; International and National Elements. Mr. Foxwell is
a chartered engineer with more than 25 years of experience in international
telecommunications networks.
 
    SIMON JOLYON GILLING.  Mr. Gilling has served as Vice President, European
Legal Affairs of Viatel since May 1999. Prior to joining Viatel, Mr. Gilling was
a consultant from July 1998 to May 1999. From June 1990 to July 1998, Mr.
Gilling was Partnership Secretary and Head of Legal Affairs of Mercury Personal
Communications, a personal mobile telecommunications company. From 1985 to May
1990, Mr. Gilling was the Company secretary and Senior Legal Adviser for Mercury
Communications Ltd., a wholly owned subsidiary of Cable and Wireless PLC.
 
    PAUL K. HEUN.  Mr. Heun has been Vice President, Operations of Viatel since
January 1998. Prior to joining Viatel, Mr. Heun was Vice President, Network
Services of Primus Telecommunications Group from October 1997 to January 1998.
From April 1996 to October 1997, Mr. Heun was Vice President, Network Services
of Telepassport, Inc. From January 1995 to April 1996, Mr. Heun was employed by
AT&T as Manager, Customer Connectivity. From April 1989 to January 1995, Mr.
Heun was employed by MCI, most recently as Senior Manager, Network Operations.
 
    FRED HUGHES.  Mr. Hughes has served as Vice President, Engineering of Viatel
since December 1997. From July 1994 to December 1997, Mr. Hughes was Vice
President, Operations-Europe of Viatel. From August 1993 to July 1994, Mr.
Hughes served as Director of Telephony of the company. From January 1991 to
August 1993, Mr. Hughes was President of Communications Services Group, a
Connecticut-based voice and data communications consulting company. From August
1988 to January 1991, Mr. Hughes was Director of Engineering at Millicom
Telecommunications Services, Inc.
 
    EVAN MILLER.  Mr. Miller has served as Vice President of Business
Development of Viatel since February 1999. Prior to joining the company, Mr.
Miller was Director, Equity Research at Credit Suisse First Boston from March
1995 to December 1998 and was Director, Equity Research at Lehman Brothers from
December 1990 to February 1995. From April 1988 to November 1990, Mr. Miller was
a member of the Senior Management Group, Corporate Strategy at British Telecom.
 
    WAYNE MYERS.  Mr. Myers has been Vice President, European Sales of Viatel
since January 1999. Prior to becoming Vice President, European Sales, Mr. Myers
served as General Manager, European Sales of the company from July 1997 to
January 1999. From February 1996 to June 1997, Mr. Myers was Channel Sales
Director of PSI Net. From November 1994 to February 1996, Mr. Myers was a Sales
Director for LDDS/WorldCom. From June 1993 to November 1994, Mr. Myers was
President of the Gold Club, a direct
 
                                       61
<PAGE>
mail Company. From February 1988 to June 1993, Mr. Myers was employed by Cable &
Wireless Communications, Inc. in various capacities, most recently as a National
Account Director.
 
    JAN S. PIAZZA.  Mr. Piazza has been Vice President, Carrier Sales since
January 1999. Prior to becoming Vice President, Carrier Sales, Ms. Piazza served
as Viatel's General Manager, Carrier Sales from January 1998 to January 1999.
Prior to joining Viatel, Ms. Piazza was a Vice President of Primus
Telecommunications Group from October 1997 to December 1997. From September 1995
to October 1997, Ms. Piazza was a Vice President, Sales and Marketing of
Telepassport, Inc. From 1987 to August 1995, Ms. Piazza served in various
positions at a predecessor of WorldCom, most recently as Vice President of
Product Development and Carrier Sales. From 1983 until 1987, Ms. Piazza was
Director of Sales Administration and Customer Service for Argo Communications.
 
    ELLEN S. RUDIN.  Ms. Rudin has served as Vice President and Deputy General
Counsel of Viatel since September 1998 and as Assistant Secretary since
September 1997. Prior to becoming Vice President and Deputy General Counsel, Ms.
Rudin served as Assistant General Counsel from October 1997 to September 1998,
as Counsel from March 1997 to October 1997 and as a staff attorney from August
1996 to March 1997. From September 1987 to August 1996, Ms. Rudin was associated
with the law firm of Wien, Malkin & Bettex.
 
    PETER STEPHENS.  Mr. Stephens has been Vice President, Operations--Europe of
Viatel since January 1999. Prior to becoming Vice President, Operations--Europe,
Mr. Stephens served as Technical Director for MCI's operations in Europe, the
Middle East and Africa from January 1993 to December 1998. Prior to January
1993, Mr. Stephens was employed by Reuters in various capacities for
approximately 19 years, most recently as Communications Quality Director.
 
    Viatel's Board of Directors is comprised of seven directorships, two of
which are currently vacant. The Board consists of three classes: Class A, Class
B and Class C. One of the three classes, comprising one-third of the directors,
is elected each year to succeed the directors whose terms are expiring.
Directors hold office until the annual meeting for the year in which their terms
expire and until their successors are elected and qualified unless, prior to
that date, they have resigned, retired or otherwise left office.
 
    The Board of Directors has established three committees, a Compensation
Committee, an Audit Committee and a Directors Committee. The current members of
the Compensation Committee are Messrs. Mahoney, Graham and Pizzani, the current
members of the Audit Committee are Messrs. Graham and Pizzani and the current
members of the Directors Committee are Messrs. Mahoney, Graham and Pizzani. The
Compensation Committee reviews general policy matters relating to compensation
and benefits of employees and officers of Viatel and administers the Stock
Incentive Plan. The Audit Committee recommends to the Board the firm of
independent public accountants to audit Viatel's financial statements, reviews
with management and the independent accountants the Company's interim and
year-end operating results, considers the adequacy of the internal controls and
audit procedures of Viatel and reviews the nonaudit services to be performed by
the independent accountants. The Directors Committee searches for and interviews
prospective directors, makes recommendations to the Board regarding the size of
the Board and candidates to fill vacancies on the Board, including vacancies
created by reason of an increase in the size of the Board and nominates
candidates for election to the Board.
 
    Viatel pays an annual fee to non-employee directors of $30,000 (paid $15,000
in cash, in quarterly installments, and $15,000 in stock options), $1,200 for
every board meeting attended and held separately and $600 for each Board meeting
or committee meeting participated in by telephone. Directors who are also
employees of Viatel are not separately compensated for serving on the Board. All
directors are reimbursed for out-of-pocket expenses incurred in attending Board
and committee meetings.
 
                                       62
<PAGE>
SUMMARY COMPENSATION TABLE
 
    The following table sets forth information concerning compensation for
services in all capacities awarded to, earned by or paid to, any person acting
as Viatel's Chief Executive Officer during 1998, regardless of the amount of
compensation paid, and the other most highly compensated executive officers of
Viatel during 1998 whose aggregate cash and cash equivalent compensation
exceeded $100,000.
 
<TABLE>
<CAPTION>
                                                         ANNUAL COMPENSATION
                                                  ----------------------------------    LONG TERM COMPENSATION
                                                                           OTHER       -------------------------
                                                                           ANNUAL      RESTRICTED     SECURITIES         ALL
                                                                        COMPENSATION      STOCK       UNDERLYING        OTHER
NAME AND PRINCIPAL POSITION                 YEAR  SALARY($)   BONUS($)     ($)(1)       AWARDS($)     OPTIONS(#)   COMPENSATION(2)
- ------------------------------------------  ----  ---------   --------  ------------   -----------    ----------   ---------------
<S>                                         <C>   <C>         <C>       <C>            <C>            <C>          <C>
Michael J. Mahoney(3),....................  1998  $ 289,583   $260,000    $     --     $        --     360,771         $10,000
  President and Chief Executive Officer     1997    212,500    125,000          --              --          --           9,500
                                            1996    166,458    183,129     102,825         299,997(4)  253,333              --
 
Allan L. Shaw,............................  1998    172,917    107,500          --              --     195,019          10,000
  Senior Vice President, Finance and Chief  1997    140,000     60,000          --              --      60,666           8,400
  Financial Officer                         1996    108,333    115,000          --              --      43,333         --
 
Lawrence G. Malone,.......................  1998    155,833    110,000          --              --     138,140           9,350
  Senior Vice President, Global Sales and   1997    141,750     35,588          --              --      73,533           8,505
  Marketing                                 1996     98,333     88,147          --              --          --         --
 
Sheldon M. Goldman(5),....................  1998    182,917    112,000          --              --     162,500          10,000
  Senior Vice President, Business Affairs   1997    143,750     60,000          --              --      40,200           9,000
  and General Counsel                       1996     86,354    100,000          --              --      20,000         --
 
Francis J. Mount(6),......................  1998    175,000    107,500          --              --     122,500          10,000
  Senior Vice President, Engineering and
  Network Operations
</TABLE>
 
- ------------------------
 
(1) The amount reflected for Mr. Mahoney includes $32,416 of tax equalization
    payments, $28,227 of relocation expense reimbursement associated with Mr.
    Mahoney's repatriation from London to New York and $9,263 of tax gross ups.
 
(2) Represents matching contributions under Viatel's 401(k) plan.
 
(3) Mr. Mahoney was appointed as Chief Executive Officer in September 1997.
 
(4) Calculated based on a value of $9.00 per share, the fair market value of the
    common stock on December 31, 1996.
 
(5) Mr. Goldman began his employment with Viatel in March 1996.
 
(6) Mr. Mount began his employment with Viatel in December 1997.
 
STOCK OPTION GRANTS
 
    The following table sets forth information regarding grants of options to
purchase common stock made by Viatel during the fiscal year ended December 31,
1998 to each of the executives named in the Summary Compensation Table. No stock
appreciation rights were granted during 1998.
 
                                       63
<PAGE>
                             OPTION GRANTS IN 1998
 
<TABLE>
<CAPTION>
                                                    INDIVIDUAL GRANTS                    POTENTIAL REALIZABLE VALUE
                                  -----------------------------------------------------      AT ASSUMED ANNUAL
                                   NUMBER OF    PERCENT OF                                  RATES OF STOCK PRICE
                                  SECURITIES   TOTAL OPTIONS                                  APPRECIATION FOR
                                  UNDERLYING    GRANTED TO     EXERCISE                       OPTION TERM (3)
                                    OPTIONS    EMPLOYEES IN      PRICE      EXPIRATION   --------------------------
NAME                              GRANTED (#)    1998 (1)     ($/SHARE)(2)     DATE          (5%)         (10%)
- --------------------------------  -----------  -------------  -----------  ------------  ------------  ------------
<S>                               <C>          <C>            <C>          <C>           <C>           <C>
Michael J. Mahoney..............    90,000(4)(5)         5.0%  $    5.00     01/01/2008  $    282,600  $    717,300
                                    90,000(4)(6)         5.0        5.50     01/01/2008       311,400       789,300
                                   180,771(4)(7)        10.1       10.25     09/18/2008     1,165,973     2,953,798
 
Allan L. Shaw...................    60,000(4)(5)         3.3        5.00     01/01/2008       188,400       478,200
                                    60,000(4)(6)         3.3        5.50     01/01/2008       207,600       526,200
                                    75,019(4)(7)         4.2       10.25     09/18/2008       483,873     1,225,815
 
Lawrence G. Malone..............    27,000(4)(5)         1.5        5.00     01/01/2008        84,780       215,190
                                    60,000(4)(6)         3.3        5.50     01/01/2008       207,600       526,200
                                    51,140(4)(7)         2.9       10.25     09/18/2008       329,853       835,628
 
Sheldon M. Goldman..............    60,000(4)(5)         3.3        5.00     01/01/2008       188,400       478,200
                                    60,000(4)(6)         3.3        5.50     01/01/2008       207,600       526,200
                                    42,500(4)(7)         2.4       10.25     09/18/2008       274,125       694,450
 
Francis J. Mount................    40,000(4)(5)         2.2        5.00     01/01/2008       125,600       318,800
                                    60,000(4)(6)         3.3        5.50     01/01/2008       207,600       526,200
                                    22,500(4)(7)         1.3       10.25     09/18/2008       145,125       367,650
</TABLE>
 
- ------------------------
 
(1) Viatel granted options to purchase a total of 1,793,736 shares of common
    stock during 1998.
 
(2) The exercise price was equal to the fair market value of the shares of
    common stock underlying the options on the grant date.
 
(3) Amounts reported in these columns represent amounts that may be realized
    upon exercise of options immediately prior to the expiration of their term
    assuming the specified compounded rates of appreciation (5% and 10%) on the
    common stock over the term of the options. These assumptions are based on
    rules promulgated by the Commission and do not reflect Viatel's estimate of
    future stock price appreciation. Actual gains, if any, on the stock option
    exercises and common stock holdings are dependent on the timing of such
    exercise and the future performance of the common stock. There can be no
    assurance that the rates of appreciation assumed in this table can be
    achieved or that the amounts reflected will be received by the option
    holder.
 
(4) In the event of certain Corporate Transactions (as defined) involving
    Viatel, all unvested stock options become fully vested. See "--Stock
    Incentive Plan." The options granted to the Named Executives also vest upon
    a change of control.
 
(5) Options to purchase shares of common stock vested and became exercisable as
    to 33.34% of these options on January 1, 1999 and the remainder will vest
    and become exercisable on each successive anniversary date thereafter to the
    extent of 33.33% of these options.
 
(6) Options to purchase shares of common stock vested and became exercisable as
    to 25% of these options on January 1, 1999 and the remainder will vest and
    become exercisable on each successive anniversary date thereafter to the
    extent of 25% of these options.
 
(7) Options to purchase shares of common stock will vest and become exercisable
    as to 33.34% of these options on September 18, 1999 and the remainder will
    vest and become exercisable on each successive anniversary date thereafter
    to the extent of 33.33% of these options.
 
                                       64
<PAGE>
    On January 1, 1999, Viatel granted the following stock options, with an
exercise price of $22.875 per share, to the executives named in the Summary
Compensation Table: Michael J. Mahoney, 52,278 options; Allan L. Shaw, 38,519
options; Lawrence G. Malone, 38,519 options; Sheldon M. Goldman, 38,519 options;
and Francis J. Mount, 38,519 options.
 
YEAR-END OPTION VALUES
 
    The following table sets forth information regarding the number and year end
value of unexercised options held at December 31, 1998 by each of the executives
named in the Summary Compensation Table. No stock appreciation rights were
exercised by these executives during fiscal 1998.
 
                       FISCAL 1998 YEAR-END OPTION VALUES
 
<TABLE>
<CAPTION>
                                                                                       VALUE OF UNEXERCISED
                                                            NUMBER OF SECURITIES          "IN-THE-MONEY"
                                                           UNDERLYING UNEXERCISED       OPTIONS AT FISCAL
                                  SHARES         VALUE        OPTIONS AT FISCAL            YEAR-END ($)
                                ACQUIRED ON    REALIZED         YEAR-END (#)        EXERCISABLE/UNEXERCISABLE
NAME                           EXERCISE (#)       ($)      EXERCISABLE/UNEXERCISABLE            (1)
- -----------------------------  -------------  -----------  -----------------------  --------------------------
<S>                            <C>            <C>          <C>                      <C>
Michael J. Mahoney...........       46,666     $ 662,891(2)     217,820/368,265       $3,372,766/$5,179,939
Allan L. Shaw................       --            --           132,116/180,235         2,144,123/2,724,471
Lawrence G. Malone...........       --            --           105,249/149,757         1,713,119/2,298,995
Sheldon M. Goldman...........       --            --           81,805/179,414          1,330,560/2,219,277
Francis J. Mount.............           --            --        28,360/94,140           499,435/1,542,128
</TABLE>
 
- ------------------------
 
(1) Options are "in-the-money" if the fair market value of the underlying
    securities exceeds the exercise price of the options. The amounts set forth
    represent the difference between $22.875 per share, the fair market value of
    the common stock issuable upon exercise of options at December 31, 1998 and
    the exercise price of the option, multiplied by the applicable number of
    options.
 
(2) The amounts set forth represent the difference between $19.00 per share, the
    fair market value of the common stock issuable upon exercise of options at
    July 27, 1998, and the exercise price of the option, multiplied by the
    applicable number of options.
 
EMPLOYMENT AGREEMENTS
 
    Viatel has executed employment agreements with Messrs. Mahoney, Shaw and
Goldman, each dated April 1, 1998, pursuant to which Mr. Mahoney serves as
President and Chief Executive Officer of the company, Mr. Shaw serves as Senior
Vice President, Finance and Chief Financial Officer and Mr. Goldman serves as
Senior Vice President, Business Affairs and General Counsel for Viatel. In
addition, Viatel intends to execute employment agreements with Messrs. Lawrence
Malone and Francis Mount, pursuant to which Mr. Malone will continue to serve as
Senior Vice President, Global Sales and Marketing and Mr. Mount will continue to
serve as Senior Vice President, Engineering and Network Operations. The term of
the Mahoney employment agreement extends for a period of three years, the term
of the Shaw and Goldman employment agreements extend for a period of two years,
and the term of the Malone and Mount employment agreements will extend for a
period of two years, in each case unless earlier terminated in accordance with
the terms thereof. Pursuant to the respective employment agreements, Mr. Mahoney
is entitled to receive an annual base salary of $300,000 (subject to
adjustments), Mr. Shaw is entitled to receive an annual base salary of $175,000
and Mr. Goldman is entitled to receive an annual base salary of $185,000
subject, in each case, to increases approved from time to time by the Board. In
addition, Mr. Mahoney's Employment Agreement provides for an annual cash bonus
payment equal to 70% of his base salary multiplied by a bonus multiple ranging
from 0.6 to 2.0 determined based upon a comparison of actual versus projected
EBITDA and revenue figures and each of Messrs. Shaw's and Goldman's employment
agreement provides for an annual cash bonus payment equal to 50% of their base
salary multiplied by a bonus multiple ranging from 0.6 to 2.0 determined based
upon a comparison of
 
                                       65
<PAGE>
actual versus projected EBITDA and revenue figures. Each of the employment
agreements also provides that the executive will be entitled to receive annual
grants of stock options or restricted stock in amounts to be determined by the
Board of Directors in its sole and absolute discretion and provides that
following a change of control (as defined therein), Viatel will be obligated to
pay the executive an amount equal to the Severance Amount (as defined therein)
if the executive chooses to terminate his employment and include a
non-competition covenant. Each of the employment agreements also contains a
prohibition on the solicitation of Viatel employees. The Malone and Mount
employment agreements will contain minimum salary amounts, potential bonus
amounts and other provisions similar to those contained in the Shaw and Goldman
employment agreements.
 
    For purposes of the Mahoney, Shaw and Goldman employment agreements, "change
of control" is defined to mean such time as (1) a "person" or "group" (within
the meaning of Sections 13(d) and 14(d)(2) of the Securities Exchange Act of
1934, as amended (the "Exchange Act")), becomes the ultimate "beneficial owner"
(as defined in Rule 13d-3 of the Exchange Act) of more than 50% of the total
voting power of the then outstanding voting stock of Viatel on a fully diluted
basis or (2) individuals who at the beginning of any period of two consecutive
calendar years constituted the Board (together with any new directors whose
election by the Board or whose nomination for election by Viatel's stockholders
was approved by a vote of at least two-thirds of the members of the Board then
still in office who either were members of the Board at the beginning of this
period or whose election or nomination for election was previously so approved)
cease for any reason to constitute a majority of the members of the Board then
in office.
 
STOCK INCENTIVE PLAN
 
    Viatel has adopted the Amended Stock Incentive Plan (the "Stock Incentive
Plan") under which "non-qualified" stock options to acquire shares of common
stock may be granted to employees, directors and consultants of Viatel and
"incentive" stock options to acquire shares of common stock may be granted to
employees, including employee-directors. The Stock Incentive Plan also provides
for the grant of stock appreciation rights and shares of restricted common stock
to Viatel's employees, directors and consultants.
 
    The Stock Incentive Plan provides for the issuance of up to a maximum of
4,166,666 shares of common stock and is administered by the Compensation
Committee of the Board. Under the Stock Incentive Plan, the option price of any
incentive stock option may not be less than the fair market value of a share of
common stock on the date on which the option is granted. The option price of a
non-qualified stock option may be less than the fair market value on the date
the non-qualified stock option is granted if the Board of Directors so
determines. An incentive stock option may not be granted to a "ten percent
stockholder" (as that term is defined in Section 422A of the Code) unless the
exercise price is at least 110.0% of the fair market value of the common stock
and the term of the option may not exceed five years from the date of grant.
Each option granted pursuant to the Stock Incentive Plan is evidenced by a
written agreement executed by Viatel and the grantee, which contains the terms,
provisions and conditions of the grant. Stock options may not be assigned or
transferred during the lifetime of the holder except as may be required by law
or pursuant to a qualified domestic relations order. Common stock subject to a
restricted stock purchase or bonus agreement is transferable only as provided in
that agreement. The maximum term of each stock option granted to persons other
than ten percent stockholders is ten years from the date of grant.
 
    For options to qualify as incentive stock options, the aggregate fair market
value, determined on the date of grant, of the shares with respect to which the
incentive stock options are exercisable for the first time by the grantee during
any calendar year may not exceed $100,000. Payment by option holders upon
exercise of an option may be made in cash or, with the consent of the Board of
Directors, in whole or in part,
 
    -  with shares of common stock,
 
                                       66
<PAGE>
    -  by irrevocable direction to an approved securities broker to sell shares
       and deliver all or a portion of the proceeds to Viatel,
 
    -  by delivery of a promissory note with any provisions that the Board of
       Directors determines appropriate or
 
    -  in any combination of these three possibilities.
 
    In addition, the Board of Directors, in its sole discretion, may authorize
the surrender by an optionee of all or part of an unexercised stock option and
authorize a payment in consideration thereof of an amount equal to the
difference between the aggregate fair market value of the shares of common stock
subject to this stock option and the aggregate option price per share of such
common stock. In the Board of Directors' discretion, this payment may be made in
cash, shares of common stock with a fair market value on the date of surrender
equal to the payment amount or some combination of the two.
 
    The Stock Incentive Plan provides that outstanding options, restricted
shares of common stock or stock appreciation rights vest in their entirety and
become exercisable, or with respect to restricted common stock, are released
from restrictions on transfer and repurchase rights, in the event of a
"Corporate Transaction." For purposes of the Stock Incentive Plan, a Corporate
Transaction includes any of the following stockholder-approved transactions to
which Viatel is a party:
 
    -  a merger or consolidation in which Viatel is not the surviving entity,
       other than a transaction the principal purpose of which is to change the
       state of Viatel's incorporation, or a transaction in which Viatel's
       stockholders immediately prior to the merger or consolidation hold (by
       virtue of securities received in exchange for their shares in Viatel)
       securities of the surviving entity representing more than 50.0% of the
       total voting power of that entity immediately after the transaction;
 
    -  the sale, transfer or other disposition of all or substantially all of
       the assets of Viatel unless Viatel's stockholders immediately prior to
       the sale, transfer or other disposition hold (by virtue of securities
       received in exchange for their shares in Viatel) securities of the
       purchaser or other transferee representing more than 50.0% of the total
       voting power of that entity immediately after the transaction; or
 
    -  any reverse merger in which Viatel is the surviving entity but in which
       Viatel's stockholders immediately prior to the merger do not hold (by
       virtue of their shares in Viatel held immediately prior to such
       transaction) securities of Viatel representing more than 50.0% of the
       total voting power of Viatel immediately after the transaction.
 
COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION
 
    During 1998, the members of the Compensation Committee were Messrs. Pizzani,
Mahoney and Graham. Mr. Mahoney is Viatel's President and Chief Executive
Officer. None of the executive officers of Viatel currently serves on the
compensation committee of another entity or any other committee of the board of
directors of another entity performing functions similar to the Compensation
Committee. No interlocking relationships exist between Viatel's Board of
Directors or its Compensation Committee and the board of directors or
compensation committee of any other company.
 
                                       67
<PAGE>
                              CERTAIN TRANSACTIONS
 
    On June 3, 1998, we entered into a Mutual Cooperation Agreement with Martin
Varsavsky and Jazz Telecom S.A. pursuant to which the parties made certain
agreements including the following: (1) subject to Jazz Telecom S.A. completing
a high yield offering with net proceeds to Jazz Telecom S.A. of at least $100
million (the "Offering Condition"), we and Jazz Telecom S.A. agreed to use
commercially reasonable efforts to execute and deliver a construction agreement
no later than January 1, 1999 to construct a fiber optic submarine cable system
between Spain and the United Kingdom, (2) subject to the Offering Condition, we
agreed to purchase $6.0 million of Jazz Telecom S.A. common stock, (3) we and
Jazz Telecom S.A. agreed to the purchase from the other international switched
minutes and we agreed to transmit at least one-third of our Spanish domestic
switched minute traffic over Jazz Telecom S.A.'s network, assuming the prices
charged by Jazz Telecom S. A. are competitive, (4) we and Jazz Telecom S.A.
agreed to sell capacity to each other for fixed prices, (5) Mr. Varsavsky agreed
to lock-up his Viatel shares for a specified period, (6) we agreed to release
any past claims which we had against either Jazz Telecom S.A. and Mr. Varsavsky
in exchange for their respective release of any claims against us, and (7) Mr.
Varsavsky agreed to pay us liquidated damages in the event that he violates
certain provisions of the agreement. We and Jazz Telecom S.A. are in discussions
concerning certain modifications to the terms of the Mutual Cooperation
Agreement.
 
    On November 13, 1998, Mr. Varsavsky entered into an additional lock-up
agreement with us pursuant to which Mr. Varsavsky agreed that he would not sell,
contract to sell, announce an intention to sell, pledge or otherwise dispose of
his shares of our common stock, either directly or indirectly, without the prior
written consent of us until after August 12, 1999.
 
                                       68
<PAGE>
                       PRINCIPAL AND SELLING STOCKHOLDERS
 
    The following table sets forth certain information regarding the beneficial
ownership of Viatel's common stock, as of May 19, 1999, and as adjusted to
reflect the sale of the shares offered hereby, by (1) each person known to
Viatel to own beneficially more than 5% of its outstanding shares of common
stock, (2) each director of Viatel, (3) each person named in the Summary
Compensation Table under "Management", and (4) all executive officers and
directors of Viatel, as a group, together with their respective percentage
ownership of such shares before and after the offering. All information with
respect to beneficial ownership has been furnished to Viatel by the respective
stockholders of Viatel.
 
<TABLE>
<CAPTION>
                                                 TOTAL       SHARES BENEFICIALLY                 SHARES BENEFICIALLY
                                               SHARES AND      OWNED PRIOR TO                        OWNED AFTER
                                                OPTIONS          OFFERING(1)         SHARES           OFFERING
NAME AND ADDRESS OF                            ----------  -----------------------    BEING    -----------------------
BENEFICIAL OWNER                                 NUMBER      NUMBER      PERCENT     OFFERED     NUMBER      PERCENT
- ---------------------------------------------  ----------  ----------  -----------  ---------  ----------  -----------
<S>                                            <C>         <C>         <C>          <C>        <C>         <C>
Martin Varsavsky
  Parque Empresarial Edificio 2,
  c/o Beatriz De Bobadilla
  14,5 Ofic. B
  Madrid, Spain..............................   3,596,666   3,596,666        12.9%    500,000                       %
The Capital Guardian Trust Co.
  11100 Santa Monica Boulevard
  Los Angeles, CA 90025-3384(2)..............   2,695,700   2,695,700
Michael J. Mahoney(3)........................     739,362     318,819         1.1
Allan L. Shaw(3).............................     371,870     153,116       *
Lawrence G. Malone(3)........................     309,525     132,359       *
Sheldon M. Goldman(3)(4).....................     285,219     105,805       *
Francis J. Mount(3)..........................     177,019      44,336       *
John G. Graham(3)............................       2,463       2,097       *
Paul G. Pizzani(3)...........................       1,463       1,097       *
All directors and executive
  officers as a group (7 persons)(5).........   1,886,921     757,629         2.7%    200,000
</TABLE>
 
- ------------------------
 
*   Represents beneficial ownership of less than 1% of the outstanding shares of
    common stock.
 
(1) Beneficial ownership is determined in accordance with the rules of the
    Commission. In computing the number of shares beneficially owned by a person
    and the percentage ownership of that person, shares of common stock subject
    to options and warrants held by that person that are currently exercisable
    or exercisable within 60 days of May 19, 1999 are deemed outstanding. Such
    shares, however, are not deemed outstanding for the purpose of computing the
    percentage ownership of any other person. Except as indicated in the
    footnotes to this table, the stockholder named in the table has sole voting
    and investment power with respect to the shares set forth opposite such
    stockholder's name.
 
(2) The amount reported reflects shares held by Capital Guardian Trust Company
    solely as the investment manager of various institutional accounts. The
    Capital Guardian Trust Company does not have investment power or voting
    power over any of these shares.
 
(3) Includes shares of common stock which these individuals have the right to
    acquire through the exercise of options within 60 days of May 19, 1999, as
    follows: Michael J. Mahoney 217,820; Allan L. Shaw 132,116; Lawrence G.
    Malone 116,359; Sheldon M. Goldman 81,805; Francis J. Mount 28,336; John G.
    Graham, 1,097; and Paul G. Pizzani, 1,097.
 
(4) Includes 1,000 shares owned by Mr. Goldman's wife. Mr. Goldman disclaims
    "beneficial ownership" of such shares within the meaning of Rule 13d-3 under
    the Exchange Act.
 
(5) Includes vested and exercisable options to purchase 578,654 shares of common
    stock which were granted pursuant to the Stock Incentive Plan.
 
                                       69
<PAGE>
                          DESCRIPTION OF CAPITAL STOCK
 
GENERAL
 
    Our authorized capital stock consists of (i) 50.0 million shares of common
stock, and (ii) 2.0 million shares of preferred stock. As of May 19, 1999, there
were 27,832,363 shares of common stock and no shares of preferred stock issued
and outstanding.
 
    The statements under this caption are brief summaries of certain material
provisions of our certificate of incorporation and by-laws. These summaries do
not purport to be complete, and are subject to, and are qualified in their
entirety by reference to, such documents.
 
COMMON STOCK
 
    Holders of our common stock are entitled to one vote per share on all
matters on which the holders of common stock are entitled to vote and do not
have any cumulative voting rights. This means that the holders of more than
50.0% of our common stock voting for the election of directors can elect all of
the directors up for election if they choose to do so; if this event occurs, the
holders of the remaining shares of our common stock will not be able to elect
any person to our board of directors. Subject to the rights of the holders of
shares of our preferred stock, holders of our common stock are entitled to
receive ratably such dividends as may be from time to time declared by our board
of directors out of funds legally available for this purpose. Holders of our
common stock are not entitled to any preemptive, conversion, redemption,
subscription or similar rights. In the event of a liquidation, dissolution or
winding up of Viatel, whether voluntary or involuntary, holders of our common
stock are entitled to share proportionately in any assets which remain after we
have paid all of our debts and other liabilities and reserved any amounts due to
holders of our outstanding preferred stock.
 
PREFERRED STOCK
 
    Our certificate of incorporation authorizes our board of directors to issue,
from time to time, up to two million shares of preferred stock in one or more
series. The board is authorized to fix or alter the specific rights of each
series, including:
 
    - dividend rights,
 
    - dividend rates,
 
    - conversion rights,
 
    - voting rights,
 
    - terms of redemption,
 
    - redemption prices,
 
    - liquidation preferences, and
 
    - the number of shares of each series.
 
The issuance of preferred stock could delay, deter or prevent a change in
control of Viatel. See "Risk Factors--Certain Provisions of Our Corporate
Documents and Our Employment Contracts May Make a Takeover More Difficult Even
If the Takeover Would Benefit Stockholders."
 
CERTIFICATE OF INCORPORATION AND BY-LAWS
 
    Our certificate of incorporation provides that no director shall be liable
to Viatel or its stockholders for monetary damages for breach of his or her
fiduciary duty as a director, except for liability:
 
    - for any breach of the director's duty of loyalty to Viatel or its
      stockholders,
 
                                       70
<PAGE>
    - for acts or omissions not in good faith or which involve intentional
      misconduct or a knowing violation of law,
 
    - in respect of certain unlawful dividend payments or stock redemptions or
      repurchases, or
 
    - for any transaction from which the director derived an improper personal
      benefit.
 
    These provisions effectively eliminate our right and the right of our
stockholders, through stockholders' derivative suits on behalf of Viatel, to
recover monetary damages against a director for breach of fiduciary duty as a
director, including breaches resulting from grossly negligent behavior, except
in the situations described above.
 
    Our by-laws require that we indemnify any of our legal representatives,
directors and officers and any person who is or was serving at our request as a
director, officer, employee or agent of another corporation or of a partnership,
joint venture, trust or other enterprise, including service with respect to
employee benefit plans, to the fullest extent authorized by the DGCL.
 
    We have obtained officers' and directors' liability insurance in the amount
of $15 million for members of our board of directors and executive officers. We
have entered into agreements to indemnify our directors and officers from and
against any expenses incurred by them in connection with certain legal matters
arising from their service to, or at request of, Viatel. The indemnity
agreements contain provisions designed to protect against the loss of the
contemplated benefits in the event of a change in control.
 
    Our certificate of incorporation and by-laws include provisions which may
delay, deter or prevent a future takeover or change in control of Viatel unless
the transaction is approved by our board of directors. These provisions may also
render the removal of directors and management more difficult.
 
    Our certificate of incorporation divides our board of directors into three
classes, as equal in number as possible, serving staggered, three-year terms.
Our by-laws contain provisions which require that stockholders give Viatel prior
notice of their intent to either nominate a director or submit a proposal for
consideration at the annual meeting. In general, we must receive notice no less
than 120 days prior to the meeting. This notice must contain specified
information regarding (1) the person to be nominated or the matter to be brought
before the meeting and (2) the stockholder submitting the proposal.
 
DELAWARE ANTI-TAKEOVER LAW
 
    We are subject to the provisions of Section 203 of the DGCL. The DGCL
generally prohibits a publicly-held company from engaging in a business
combination with an interested stockholder for a period of three years after the
date of the transaction in which the person became an interested stockholder,
unless the interested stockholder attained that status with the approval of the
board or unless the business combination is approved in a prescribed manner. A
business combination includes mergers, asset sales, and other transactions
resulting in a financial benefit to the interested stockholder. Subject to
certain exceptions, an interested stockholder is a person who, together with
affiliates and associates, owns, or within three years did own, fifteen percent
or more of a corporation's voting stock. This statute could prohibit or delay
the accomplishment of mergers or other takeover or change in control attempts
with respect to us and, accordingly, may discourage attempts to acquire us.
 
REGISTRATION RIGHTS
 
    In connection with our 1998 high yield offering, we agreed to register, no
later than April 8, 1999, the shares of our common stock which will be issued
upon conversion of our outstanding preferred stock and subordinated convertible
debentures. The required registration has been declared effective by the SEC.
Subject to limited exceptions, we are required to keep the registration
statement current and available for use for a period of two years or until all
the unregistered notes have been sold under the registration statement, if
earlier.
 
                                       71
<PAGE>
    In connection with our 1999 high yield offering, we agreed to use our best
efforts to complete, at our expense, by September 19, 1999, a registered
exchange offer for each of the two series of notes which were issued. Under the
terms of our agreement, we are required to offer to exchange registered notes
which have terms substantially identical to those of the notes originally sold
by us on a private placement basis in our March 1999 offering. In the event we
are unable to complete the exchange offer due to a change in SEC policy, we are
required to use our best efforts to put in place a shelf registration statement
for the sale of the unregistered notes by the respective holders. We are
required to keep any shelf registration which we file current and available for
use for up to two years or until all the unregistered notes have been sold under
the registration statement, if earlier. If we do not complete the registered
exchange offer or have the shelf registration statement in place within the
required time frames, we will be required to pay specified penalties.
 
                                       72
<PAGE>
         CERTAIN UNITED STATES TAX CONSEQUENCES FOR NON-U.S. INVESTORS
 
INTRODUCTION
 
    The following is a summary of certain United States federal tax consequences
to non-U.S. investors of owning and disposing of common stock. In this summary,
"non-U.S. investor" means:
 
    - a nonresident alien individual;
 
    - a foreign corporation;
 
    - a nonresident alien fiduciary of a foreign estate or trust; or
 
    - a foreign partnership, one or more members of which is, for U.S. tax
      purposes, a nonresident alien individual, a foreign corporation, or a
      nonresident alien fiduciary of a foreign estate or trust.
 
    This summary does not address all of the federal tax considerations that may
be relevant to you in light of your particular circumstances and also does not
discuss any state, local or foreign tax. This summary is based on current
provisions of the Internal Revenue Code, Treasury regulations, judicial
opinions, published positions of the Internal Revenue Service (the "IRS") and
other applicable authorities. These authorities are all subject to change,
possibly with retroactive effect. If you are considering buying common stock,
you should consult your tax advisor with respect to the tax consequences of
investing in the common stock.
 
DIVIDENDS
 
    Dividends paid to a non-U.S. investor generally will be subject to
withholding of federal income tax at a 30% rate or such lower rate as may be
specified by an applicable income tax treaty. To receive a reduced treaty rate,
you must furnish to us or our paying agent a completed IRS Form 1001 or W-8BEN
(or substitute form) certifying that you qualify for a reduced rate. Dividends
that are effectively connected with the conduct of a trade or business within
the United States or, if a treaty applies, attributable to a permanent
establishment within the United States, will be exempt if you provide us with an
IRS Form 4224 or IRS Form W-8ECI (or substitute form). Dividends exempt from
withholding because they are effectively connected or attributable to a
permanent establishment will instead be taxed at ordinary federal income tax
rates on a net income basis. Further, if the non-U.S. investor is a corporation,
this effectively connected dividend income may also be subject to an additional
branch profits tax. Under current Treasury regulations, dividends paid before
January 1, 2001 to an address outside the United States are presumed to be paid
to a resident of the country of address for purposes of the withholding
discussed above and for purposes of determining the applicability of a tax
treaty rate. However, for dividends paid after December 31, 2000, this
presumption is eliminated.
 
SALE OR OTHER DISPOSITION OF COMMON STOCK
 
    A non-U.S. investor generally will not be subject to federal income tax on
any gain recognized on the sale or other disposition of common stock, except in
the following circumstances:
 
    (1) The gain will be subject to federal income tax if it is effectively
       connected with a trade or business of the non-U.S. investor within the
       United States or, if a treaty applies, is attributable to a permanent
       establishment. Unless an applicable treaty provides otherwise, the
       non-U.S. investor will be taxed on its net gains derived from the sale
       under regular graduated U.S. federal income tax rates. If the non-U.S.
       investor is a foreign corporation, it may be subject to an additional
       branch profits tax.
 
    (2) The gain will be subject to federal income tax if the non-U.S. investor
       is an individual who holds the common stock as a capital asset, is
       present in the United States for 183 or more days in the taxable year of
       the sale or other disposition, and certain other conditions are met.
 
                                       73
<PAGE>
    (3) The gain may be subject to federal income tax pursuant to federal income
       tax laws applicable to certain expatriates.
 
    (4) The gain may be subject to federal income tax if we are or have been
       during certain periods a "United States real property holding
       corporation" and the non-U.S. investor held, at any time during the
       five-year period ending on the date of disposition (or, if shorter, the
       non-U.S. investor's holding period), more than 5 percent of the
       outstanding common stock. We believe that it will not constitute a United
       States real property holding corporation immediately after the offering
       and does not expect to become a United States real property holding
       corporation; however, we can give no assurance in this regard.
 
BACKUP WITHHOLDING AND INFORMATION REPORTING
 
    DIVIDENDS. United States backup withholding tax generally will not apply to
dividends paid before January 1, 2000 to a non-U.S. investor at an address
outside the United States, or to dividends paid after December 31, 2000 if the
non-U.S. investor certifies that it is a non-U.S. investor on an IRS Form W-8BEN
or otherwise establishes an exemption. We must report annually to the IRS and to
each non-U.S.investor the amount of dividends paid to such investor and the
amount, if any, of tax withheld with respect to such dividends. This information
may also be made available to the tax authorities in the non-U.S. investor's
country of residence.
 
    SALE THROUGH A U.S. OFFICE OF A BROKER. Upon the sale or other disposition
of common stock by a non-U.S. investor to or through a United States office of a
broker, the broker must backup withhold at a rate of 31% and report the sale to
the IRS, unless the investor certifies its foreign status under penalties of
perjury or otherwise establishes an exemption from backup withholding.
 
    SALE THROUGH A FOREIGN OFFICE OF A BROKER.  Upon the sale or other
disposition of common stock by a non-U.S. investor to or through a foreign
office of a United States broker or a foreign broker with certain types of
relationships with the United States, the broker is not required to backup
withhold. However, the broker must report the sale or other disposition to the
IRS unless the broker has documentary evidence in its files that the seller is a
non-U.S. investor and certain other conditions are met, or the holder otherwise
establishes an exemption.
 
    Backup withholding is not an additional tax. Amounts withheld under the
backup withholding rules are generally allowable as a refund or credit against
the non-U.S. investor's federal income tax liability, if any, provided, that the
required information is furnished to the IRS.
 
FEDERAL ESTATE TAXES
 
    Common stock owned or treated as owned by an individual who is not a citizen
or a "resident," which is specially defined for federal estate tax purposes, of
the United States at the time of death, will be included in such individual's
gross estate for federal estate tax purposes, unless an applicable estate tax
treaty provides otherwise.
 
                                       74
<PAGE>
                                  UNDERWRITERS
 
    Under the terms and subject to the conditions contained in an underwriting
agreement dated the date hereof (the "underwriting agreement"), the U.S.
underwriters named below, for whom Morgan Stanley & Co. Incorporated,
and          are acting as U.S. representatives, and the international
underwriters named below, for whom Morgan Stanley & Co. International Limited,
         and          are acting as international representatives, have
severally agreed to purchase, and Viatel and the selling stockholders have
agreed to sell to them, severally, the respective number of shares of common
stock set forth opposite the names of such underwriters below:
 
<TABLE>
<CAPTION>
                                                                                                          NUMBER OF
NAME                                                                                                       SHARES
- ------------------------------------------------------------------------------------------------------  -------------
<S>                                                                                                     <C>
U.S. Underwriters:
  Morgan Stanley & Co. Incorporated...................................................................
 
                                                                                                              -----
    Subtotal..........................................................................................
                                                                                                              -----
                                                                                                              -----
International Underwriters:
  Morgan Stanley & Co. International Limited..........................................................
    Subtotal..........................................................................................
                                                                                                              -----
      Total...........................................................................................
                                                                                                              -----
                                                                                                              -----
</TABLE>
 
    The U.S. underwriters and the international underwriters, and the U.S.
representatives and the international representatives, are collectively referred
to as the "underwriters" and the "representatives", respectively. The
underwriters are offering the shares of common stock subject to their acceptance
of the shares from Viatel and the selling stockholders and subject to prior
sale. The underwriting agreement provides that the obligations of the several
underwriters to pay for and accept delivery of the shares of common stock
offered hereby are subject to the approval of certain legal matters by their
counsel and to certain other conditions. The underwriters are obligated to take
and pay for all of the shares of common stock offered by this prospectus (other
than those covered by the U.S. underwriters' over-allotment option described
below) if any such shares are taken.
 
    Pursuant to the agreement between U.S. and international underwriters, each
U.S. underwriter has represented and agreed that, with certain exceptions: (1)
it is not purchasing any shares (as defined herein) for the account of anyone
other than a United States or Canadian Person (as defined herein) and (2) it has
not offered or sold, and will not offer or sell, directly or indirectly, any
shares or distribute any prospectus relating to the shares outside the United
States or Canada or to anyone other than a United States or Canadian Person.
Pursuant to the agreement between U.S. and international underwriters, each
international underwriter has represented and agreed that, with certain
exceptions: (1) it is not purchasing any shares for the account of any United
States or Canadian Person and (2) it has not offered or sold, and will not offer
or sell, directly or indirectly, any shares or distribute any prospectus
relating to the shares in the United States or Canada or to any United States or
Canadian Person. With respect to any underwriter that is a U.S. underwriter and
an international underwriter, the foregoing representations and agreements (1)
made by it in its capacity as a U.S. underwriter apply only to it in its
capacity as a U.S. underwriter and (2) made by it in its capacity as an
international underwriter apply only to it in its capacity as an international
underwriter. The foregoing limitations do not apply to stabilization
transactions or to certain other transactions specified in the agreement between
U.S. and international underwriters. As used herein, "United States or Canadian
Person" means any national or resident of the United States or Canada, or any
 
                                       75
<PAGE>
corporation, pension, profit-sharing or other trust or other entity organized
under the laws of the United States or Canada or of any political subdivision
thereof (other than a branch located outside the United States and Canada of any
United States or Canadian Person), and includes any United States or Canadian
branch of a person who is otherwise not a United States or Canadian Person. All
shares of common stock to be purchased by the underwriters under the
underwriting agreement are referred to herein as "shares".
 
    Pursuant to the agreement between U.S. and international underwriters, sales
may be made between the U.S. underwriters and international underwriters of any
number of shares as may be mutually agreed. The per share price of any shares so
sold shall be the public offering price set forth on the cover page hereof, in
United States dollars, less an amount not greater than the per share amount of
the concession to dealers set forth below.
 
    Pursuant to the agreement between U.S. and international underwriters, each
U.S. underwriter has represented that it has not offered or sold, and has agreed
not to offer or sell, any shares, directly or indirectly, in any province or
territory of Canada or to, or for the benefit of, any resident of any province
or territory of Canada in contravention of the securities laws thereof and has
represented that any offer or sale of shares in Canada will be made only
pursuant to an exemption from the requirement to file a prospectus in the
province or territory of Canada in which such offer or sale is made. Each U.S.
underwriter has further agreed to send to any dealer who purchases from it any
of the shares a notice stating in substance that, by purchasing such shares,
such dealer represents and agrees that it has not offered or sold, and will not
offer or sell, directly or indirectly, any of such shares in any province or
territory of Canada or to, or for the benefit of, any resident of any province
or territory of Canada in contravention of the securities laws thereof and that
any offer or sale of shares in Canada will be made only pursuant to an exemption
from the requirement to file a prospectus in the province or territory of Canada
in which such offer or sale is made, and that such dealer will deliver to any
other dealer to whom it sells any of such shares a notice containing
substantially the same statement as is contained in this sentence.
 
    Pursuant to the agreement between U.S. and international underwriters, each
international underwriter has represented and agreed that (1) it has not offered
or sold and, prior to the date six months after the closing date for the sale of
the shares to the international underwriters, will not offer or sell, any shares
to persons in the United Kingdom except to persons whose ordinary activities
involve them in acquiring, holding, managing or disposing of investments, as
principal or agent, for the purposes of their businesses or otherwise in
circumstances which have not resulted and will not result in an offer to the
public in the United Kingdom within the meaning of the Public Offers of
Securities Regulations 1995; (2) it has complied and will comply with all
applicable provisions of the Financial Services Act 1986 with respect to
anything done by it in relation to the shares in, from or otherwise involving
the United Kingdom; and (3) it has only issued or passed on and will only issue
or pass on in the United Kingdom any document received by it in connection with
the offering of the shares to a person who is of a kind described in Article
11(3) of the Financial Services Act 1986 (Investment Advertisements)
(Exemptions) Order 1996 (as amended) or is a person to whom such document may
otherwise lawfully be issued or passed on.
 
    The underwriters initially propose to offer part of the shares of common
stock directly to the public at the public offering price set forth on the cover
page hereof and part to certain dealers at a price that represents a concession
not in excess of $    a share under public offering price. Any underwriter may
allow, and such dealers may reallow, a concession not in excess of $    a share
to other underwriters or to certain other dealers. After the initial offering of
the shares of common stock, the offering price and other selling terms may from
time to time be varied by the representatives.
 
    Viatel has granted to the U.S. underwriters an option, exercisable for 30
days from the date of this prospectus, to purchase up to an aggregate of 705,000
additional shares of common stock at the public offering price set forth on the
cover page hereof, less underwriting discounts and commissions. The U.S.
underwriters may exercise such option solely for the purpose of covering
over-allotments, if any, made in
 
                                       76
<PAGE>
connection with the offering of the shares of common stock offered hereby. To
the extent such option is exercised, each U.S. underwriter will become
obligated, subject to certain conditions, to purchase approximately the same
percentage of such additional shares of common stock as the number set forth
next to such U.S. underwriter's name in the preceding table bears to the total
number of shares of common stock set forth next to the names of all U.S.
underwriters in the preceding table. If the U.S. underwriters' option is
exercised in full, the total price to the public would be $            , the
total underwriters' discounts and commissions would be $            and total
proceeds to Viatel would be $            .
 
    Each of Viatel and the directors, executive officers and certain other
stockholders of Viatel has agreed that, without the prior written consent of
Morgan Stanley & Co. Incorporated on behalf of the underwriters, it will not,
during the period ending    days after the date of this prospectus:
 
    - offer, pledge, sell, contract to sell, sell any option or contract to
      purchase, purchase any option or contract to sell, grant any option, right
      or warrant to purchase, lend or otherwise transfer or dispose of, directly
      or indirectly, any shares of common stock or any securities convertible
      into or exercisable or exchangeable for common stock; or
 
    - enter into any swap or other arrangement that transfers to another, in
      whole or in part, any of the economic consequences of ownership of the
      common stock,
 
whether any of the transactions described above is to be settled by delivery of
common stock or any other above-mentioned securities, in cash or otherwise. The
restrictions described in this paragraph do not apply to:
 
    - the sale of shares to the underwriters,
 
    - the issuance by Viatel of shares of common stock upon the exercise of an
      option or a warrant or the conversion of a security outstanding on the
      date of this prospectus of which the underwriters have been advised in
      writing; or
 
    - transactions by any person other than the company relating to shares of
      common stock or other securities acquired in open market transactions
      after the completion of the offering of the shares.
 
    In order to facilitate the offering of the common stock, the underwriters
may engage in transactions that stabilize, maintain or otherwise affect the
price of the common stock. Specifically, the underwriters may over-allot in
connection with the offering, creating a short position in the common stock for
their own account. In addition, to cover over-allotments or to stabilize the
price of the common stock, the underwriters may bid for, and purchase, shares of
common stock in the open market. Finally, the underwriting syndicate may reclaim
selling concessions allowed to an underwriter or a dealer for distributing the
common stock in the offering, if the syndicate repurchases previously
distributed common stock in transactions to cover syndicate short positions, in
stabilization transactions or otherwise. Any of these activities may stabilize
or maintain the market price of the common stock above independent market
levels. The underwriters are not required to engage in these activities, and may
end any of these activities at any time.
 
    From time to time, Morgan Stanley & Co. Incorporated has provided, and may
continue to provide investment banking services to Viatel.
 
    Viatel, the selling stockholders and the underwriters have agreed to
indemnify each other against certain liabilities, including liabilities under
the Securities Act of 1933.
 
    An affiliate of Morgan Stanley & Co. Incorporated has made a loan of
approximately $245,000 to Michael Mahoney, Viatel's Chairman and Chief Executive
Officer. The loan bears interest, is secured by approximately 48,000 shares of
common stock of Viatel, and is payable on demand.
 
                                       77
<PAGE>
                                 LEGAL MATTERS
 
    Certain legal matters in connection with this offering will be passed upon
for us by Kelley Drye & Warren LLP, New York, New York. Certain legal matters in
connection with this offering will be passed upon for the underwriters by
Shearman & Sterling, New York, New York.
 
                                    EXPERTS
 
    The consolidated financial statements of Viatel, Inc. and subsidiaries as of
December 31, 1997 and 1998 and for each of the years in the three year period
ended December 31, 1998, have been included herein and in the registration
statement in reliance upon the report of KPMG LLP, independent certified public
accountants appearing elsewhere herein, and upon the authority of said firm as
experts in accounting and auditing.
 
                  WHERE YOU CAN FIND MORE INFORMATION ABOUT US
 
    We file annual, quarterly and special reports, proxy statements and other
information with the SEC. 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 on the
public reference rooms. Our SEC filings are also available to the public at the
SEC's web site at http://www.sec.gov.
 
    You may request a copy of our annual, quarterly and special reports, proxy
statements and other information, at no cost, by writing or telephoning us at
the following address:
 
    Viatel, Inc.
    Attention: Investor Relations
    685 Third Avenue
    New York, NY 10017
    Telephone: (212) 350-9200
 
                                       78
<PAGE>
                   INDEX TO CONSOLIDATED FINANCIAL STATEMENTS
 
<TABLE>
<CAPTION>
                                                                                                              PAGE
                                                                                                            ---------
<S>                                                                                                         <C>
VIATEL, INC. AND SUBSIDIARIES
 
Independent Auditors' Report..............................................................................        F-2
 
Consolidated Balance Sheets as of December 31, 1997 and 1998..............................................        F-3
 
Consolidated Statements of Operations for the Years Ended
  December 31, 1996, 1997 and 1998........................................................................        F-4
 
Consolidated Statements of Comprehensive Loss for the Years Ended December 31, 1996, 1997 and 1998........        F-5
 
Consolidated Statements of Stockholders' Equity (Deficiency) for the
  Years ended December 31, 1996, 1997 and 1998............................................................        F-6
 
Consolidated Statements of Cash Flows for the Years ended
  December 31, 1996, 1997 and 1998........................................................................        F-7
 
Notes to Consolidated Financial Statements for the Years
  Ended December 31, 1996, 1997 and 1998..................................................................        F-8
 
Condensed Consolidated Balance Sheet as of March 31, 1999.................................................       F-22
 
Condensed Consolidated Statements of Operations for the Three Months Ended March 31, 1998 and March 31,
  1999....................................................................................................       F-23
 
Condensed Consolidated Statements of Cash Flows for the Three Months Ended March 31, 1998 and March 31,
  1999....................................................................................................       F-24
 
Notes to Condensed Consolidated Financial Statements......................................................       F-25
</TABLE>
 
                                      F-1
<PAGE>
                          INDEPENDENT AUDITORS' REPORT
 
The Board of Directors and Stockholders
Viatel, Inc.:
 
    We have audited the accompanying consolidated balance sheets of Viatel, Inc.
and subsidiaries as of December 31, 1997 and 1998, and the related consolidated
statements of operations, comprehensive loss, stockholders' equity (deficiency),
and cash flows for each of the years in the three-year period ended December 31,
1998. These consolidated financial statements are the responsibility of the
Company's management. Our responsibility is to express an opinion on these
consolidated financial statements based on our audits.
 
    We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.
 
    In our opinion, the consolidated financial statements referred to above
present fairly, in all material respects, the consolidated financial position of
Viatel, Inc. and subsidiaries as of December 31, 1997 and 1998, and the results
of their operations and their cash flows for each of the years in the three-year
period ended December 31, 1998 in conformity with generally accepted accounting
principles.
 
                                          /s/ KPMG LLP
 
New York, New York
February 26, 1999
 
                                      F-2
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
                          CONSOLIDATED BALANCE SHEETS
                           DECEMBER 31, 1997 AND 1998
                       (IN THOUSANDS, EXCEPT SHARE DATA)
 
<TABLE>
<CAPTION>
                                                                                              1997        1998
                                                                                           ----------  -----------
<S>                                                                                        <C>         <C>
                                         ASSETS
 
Current Assets:
  Cash and cash equivalents..............................................................  $   21,096  $   329,511
  Restricted cash equivalents............................................................      --           10,310
  Restricted marketable securities, current..............................................      --           50,870
  Marketable securities, current.........................................................       3,500      171,771
  Trade accounts receivable, net of allowance for doubtful accounts of $1,041 and $3,093,
    respectively.........................................................................      10,981       28,517
  Other receivables......................................................................       6,505       13,404
  Prepaid expenses.......................................................................       1,348        2,417
                                                                                           ----------  -----------
    Total current assets.................................................................      43,430      606,800
                                                                                           ----------  -----------
Restricted marketable securities, non-current............................................      --           83,343
Marketable securities, non-current.......................................................      22,547      --
Property and equipment, net..............................................................      54,094      266,256
Intangible assets, net...................................................................       4,338       46,968
Other assets.............................................................................       2,400        5,744
                                                                                           ----------  -----------
                                                                                           $  126,809  $ 1,009,111
                                                                                           ----------  -----------
                                                                                           ----------  -----------
                        LIABILITIES AND STOCKHOLDERS' DEFICIENCY
 
Current Liabilities:
  Accrued telecommunications costs.......................................................  $   16,898  $    26,518
  Accounts payable and other accrued expenses............................................      10,753       23,656
  Property and equipment purchases payable...............................................       4,739       97,288
  Accrued interest.......................................................................      --           12,240
  Liability under joint construction agreement...........................................      --            9,523
  Current installments of notes payable and obligations under capital leases.............       3,373        8,918
                                                                                           ----------  -----------
    Total current liabilities............................................................      35,763      178,143
                                                                                           ----------  -----------
Long term liabilities:
  Long term debt.........................................................................      89,855      896,503
  Notes payable and obligations under capital leases, excluding current installments.....       8,255       24,636
  Equipment purchase obligation..........................................................       1,500      --
                                                                                           ----------  -----------
    Total long term liabilities..........................................................      99,610      921,139
                                                                                           ----------  -----------
Series A Redeemable Convertible Preferred Stock, $.01 par value; Authorized 718,042
  Shares; issued and outstanding no shares and 461,258, respectively.....................      --           47,121
                                                                                           ----------  -----------
Commitments and contingencies
Stockholders' deficiency:
  Preferred Stock, $.01 par value. Authorized 1,281,958 shares, no shares issued and
    outstanding..........................................................................      --          --
  Common Stock, $.01 par value. Authorized 50,000,000 shares, issued and outstanding
    22,635,267 and 23,184,465 shares, respectively.......................................         226          232
  Additional paid-in capital.............................................................     125,661      128,357
  Unearned compensation..................................................................         (65)     --
  Accumulated other comprehensive loss...................................................      (5,356)      (6,246)
  Accumulated deficit....................................................................    (129,030)    (259,635)
                                                                                           ----------  -----------
    Total stockholders' deficiency.......................................................      (8,564)    (137,292)
                                                                                           ----------  -----------
                                                                                           $  126,809  $ 1,009,111
                                                                                           ----------  -----------
                                                                                           ----------  -----------
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                      F-3
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
                     CONSOLIDATED STATEMENTS OF OPERATIONS
 
                  YEARS ENDED DECEMBER 31, 1996, 1997 AND 1998
 
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
 
<TABLE>
<CAPTION>
                                                                                  1996        1997        1998
                                                                               ----------  ----------  -----------
<S>                                                                            <C>         <C>         <C>
Communication services revenue...............................................  $   50,419  $   73,018  $   135,188
                                                                               ----------  ----------  -----------
Operating expenses:
  Cost of communication services.............................................      42,130      63,504      122,109
  Selling, general and administrative expenses...............................      32,866      36,077       44,893
  Depreciation and amortization..............................................       4,802       7,717       16,268
                                                                               ----------  ----------  -----------
    Total operating expenses.................................................      79,798     107,298      183,270
                                                                               ----------  ----------  -----------
Other income (expenses):
  Interest income............................................................       1,852       3,686       28,259
  Interest expense...........................................................     (10,848)    (12,450)     (79,177)
                                                                               ----------  ----------  -----------
Loss before extraordinary loss...............................................     (38,375)    (43,044)     (99,000)
  Extraordinary loss on debt prepayment......................................          --          --      (28,304)
                                                                               ----------  ----------  -----------
Net loss.....................................................................     (38,375)    (43,044)    (127,304)
  Dividends on redeemable convertible preferred stock........................          --          --       (3,301)
                                                                               ----------  ----------  -----------
Net loss attributable to common stockholders.................................  $  (38,375) $  (43,044) $  (130,605)
                                                                               ----------  ----------  -----------
                                                                               ----------  ----------  -----------
Loss per common share, basic and diluted:
    Before extraordinary item................................................  $    (2.47) $    (1.90) $     (4.44)
    From extraordinary item..................................................  $       --  $       --  $     (1.23)
                                                                               ----------  ----------  -----------
    Net loss attributable to common stockholders.............................  $    (2.47) $    (1.90) $     (5.67)
                                                                               ----------  ----------  -----------
                                                                               ----------  ----------  -----------
  Weighted average common shares outstanding.................................      15,514      22,620       23,054
                                                                               ----------  ----------  -----------
                                                                               ----------  ----------  -----------
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                      F-4
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
                 CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS
 
                  YEARS ENDED DECEMBER 31, 1996, 1997 AND 1998
 
                                 (IN THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                                  1996        1997        1998
                                                                               ----------  ----------  -----------
<S>                                                                            <C>         <C>         <C>
Net loss.....................................................................  $  (38,375) $  (43,044) $  (127,304)
  Foreign currency translation adjustments...................................        (698)     (4,494)        (890)
                                                                               ----------  ----------  -----------
Comprehensive loss...........................................................  $  (39,073) $  (47,538) $  (128,194)
                                                                               ----------  ----------  -----------
                                                                               ----------  ----------  -----------
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                      F-5
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
          CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIENCY)
                  YEARS ENDED DECEMBER 31, 1996, 1997 AND 1998
                       (IN THOUSANDS, EXCEPT SHARE DATA)
<TABLE>
<CAPTION>
                                          NUMBER OF
                            NUMBER OF      CLASS A                                                             ACCUMULATED
                              COMMON       COMMON                    CLASS A    ADDITIONAL                        OTHER
                              STOCK         STOCK       COMMON       COMMON       PAID-IN       UNEARNED      COMPREHENSIVE
                              SHARES       SHARES        STOCK        STOCK       CAPITAL     COMPENSATION         LOSS
                           ------------  -----------  -----------  -----------  -----------  ---------------  --------------
<S>                        <C>           <C>          <C>          <C>          <C>          <C>              <C>
Balance at January 1,
  1996...................    10,736,135    2,904,846   $     107    $      29    $  30,099      $     (78)     $       (164)
Issuance of restricted
  common stock...........        66,666      --                1       --              389            (52)          --
Issuance of common stock,
  net of $9,541,954 issue
  costs..................     8,667,000      --               87       --           94,375         --               --
Conversion of Class A
  common stock to common
  stock..................     2,904,846   (2,904,846)         29          (29)      --             --               --
Stock options exercised..       138,579      --                1       --              373         --               --
Foreign currency
  translation
  adjustment.............       --           --           --           --           --             --                  (698)
Net loss.................       --           --           --           --           --             --               --
                           ------------  -----------       -----          ---   -----------         -----     --------------
Balance at December 31,
  1996...................    22,513,226      --              225       --          125,236           (130)             (862)
Stock options exercised..       122,041      --                1       --              425         --               --
Earned compensation......       --           --           --           --           --                 65           --
Foreign currency
  translation
  adjustment.............       --           --           --           --           --             --                (4,494)
Net loss.................       --           --           --           --           --             --               --
                           ------------  -----------       -----          ---   -----------         -----     --------------
Balance at December 31,
  1997...................    22,635,267      --              226       --          125,661            (65)           (5,356)
Stock options exercised..       174,198      --                2       --              945         --               --
Issuance costs of Series
  A Redeemable
  Convertible Preferred
  Stock..................       --           --           --           --           (1,620)        --               --
Issuance of common stock
  related to business
  purchase...............       375,000      --                4       --            3,371         --               --
Earned compensation......       --           --           --           --           --                 65           --
Foreign currency
  translation
  adjustment.............       --           --           --           --           --             --                  (890)
Dividends on redeemable
  convertible preferred
  stock..................       --           --           --           --           --             --               --
Net loss.................       --           --           --           --           --             --               --
                           ------------  -----------       -----          ---   -----------         -----     --------------
Balance at December 31,
  1998...................    23,184,465      --        $     232    $      --    $ 128,357      $  --          $     (6,246)
                           ------------  -----------       -----          ---   -----------         -----     --------------
                           ------------  -----------       -----          ---   -----------         -----     --------------
 
<CAPTION>
 
                            ACCUMULATED
                              DEFICIT         TOTAL
                           -------------  -------------
<S>                        <C>            <C>
Balance at January 1,
  1996...................  $     (47,611) $     (17,618)
Issuance of restricted
  common stock...........       --                  338
Issuance of common stock,
  net of $9,541,954 issue
  costs..................       --               94,462
Conversion of Class A
  common stock to common
  stock..................       --                   --
Stock options exercised..       --                  374
Foreign currency
  translation
  adjustment.............       --                 (698)
Net loss.................        (38,375)       (38,375)
                           -------------  -------------
Balance at December 31,
  1996...................        (85,986)        38,483
Stock options exercised..       --                  426
Earned compensation......       --                   65
Foreign currency
  translation
  adjustment.............       --               (4,494)
Net loss.................        (43,044)       (43,044)
                           -------------  -------------
Balance at December 31,
  1997...................       (129,030)        (8,564)
Stock options exercised..       --                  947
Issuance costs of Series
  A Redeemable
  Convertible Preferred
  Stock..................       --               (1,620)
Issuance of common stock
  related to business
  purchase...............       --                3,375
Earned compensation......       --                   65
Foreign currency
  translation
  adjustment.............       --                 (890)
Dividends on redeemable
  convertible preferred
  stock..................         (3,301)        (3,301)
Net loss.................       (127,304)      (127,304)
                           -------------  -------------
Balance at December 31,
  1998...................  $    (259,635) $    (137,292)
                           -------------  -------------
                           -------------  -------------
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                      F-6
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
                     CONSOLIDATED STATEMENTS OF CASH FLOWS
                  YEARS ENDED DECEMBER 31, 1996, 1997 AND 1998
                                 (IN THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                                    1996         1997         1998
                                                                                 -----------  -----------  -----------
<S>                                                                              <C>          <C>          <C>
Cash flows from operating activities:
  Net loss.....................................................................  $   (38,375) $   (43,044) $  (127,304)
  Adjustments to reconcile net loss to net cash used in operating activities:
    Depreciation and amortization..............................................        4,802        7,717       16,268
    Accreted interest expense on long term debt................................       10,783       12,479       35,417
    Provision for losses on accounts receivable................................        2,225        2,733        4,225
    Extraordinary loss on debt repayment.......................................           --           --       28,304
    Earned compensation........................................................          338           65           65
  Changes in assets and liabilities:
    Increase in accounts receivable............................................       (6,058)      (6,221)     (20,302)
    Increase in accrued interest expense on Senior Notes.......................           --           --       11,969
    Increase in prepaid expenses and other receivables.........................       (1,384)      (3,482)      (8,291)
    Increase in other assets and intangible assets.............................         (315)      (1,022)     (12,625)
    Increase in accrued telecommunications costs, accounts payable, and other
      accrued expenses.........................................................        1,653        8,250       11,956
                                                                                 -----------  -----------  -----------
      Net cash used in operating activities....................................      (26,331)     (22,525)     (60,318)
                                                                                 -----------  -----------  -----------
  Cash flows from investing activities:
    Purchase of property, equipment and software...............................       (9,423)     (34,190)     (94,674)
    Payment for business acquired excluding cash acquired of $364..............           --           --       (5,000)
    Purchase of marketable securities..........................................      (30,571)     (49,098)    (310,625)
    Proceeds from maturity of marketable securities............................       38,807       40,124       60,307
    Investment in affiliate....................................................         (102)          --           --
    Issuance of notes receivable...............................................         (303)          --           --
                                                                                 -----------  -----------  -----------
    Net cash used in investing activities......................................       (1,592)     (43,164)    (349,992)
                                                                                 -----------  -----------  -----------
  Cash flows from financing activities:
    Proceeds from issuance of long term debt...................................           --           --      845,752
    Proceeds from issuance of redeemable convertible preferred stock...........           --           --       42,198
    Prepayment of senior discount notes........................................           --           --     (119,282)
    Deferred financing costs...................................................           --           --      (31,547)
    Proceeds from issuance of Common Stock.....................................       94,836          426          947
    Borrowings on notes payable................................................           --       11,121           --
    Payments under capital leases..............................................          (64)        (525)      (5,480)
    Repayment of notes payable and bank credit line............................           --         (336)      (3,553)
    Borrowings under bank credit line..........................................           --          600           --
                                                                                 -----------  -----------  -----------
    Net cash provided by financing activities..................................       94,772       11,286      729,035
                                                                                 -----------  -----------  -----------
Effects of exchange rate changes on cash.......................................           12         (297)          --
                                                                                 -----------  -----------  -----------
Net (decrease) increase in cash and cash equivalents...........................       66,861      (54,700)     318,725
Cash and cash equivalents at beginning of year.................................        8,935       75,796       21,096
                                                                                 -----------  -----------  -----------
Cash and cash equivalents at end of year.......................................  $    75,796  $    21,096  $   339,821
                                                                                 -----------  -----------  -----------
                                                                                 -----------  -----------  -----------
Supplemental disclosures of cash flow information:
  Interest paid................................................................  $        65  $       134  $    31,560
                                                                                 -----------  -----------  -----------
                                                                                 -----------  -----------  -----------
  Assets acquired under capital lease obligations..............................  $       310  $     1,122  $    30,359
                                                                                 -----------  -----------  -----------
                                                                                 -----------  -----------  -----------
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                      F-7
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
 
                        DECEMBER 31, 1996, 1997 AND 1998
 
(1) SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
 
    (A) DESCRIPTION OF BUSINESS
 
    Viatel, Inc. (the "Company") is an international facilities-based global
provider of communications services offering international and domestic long
distance telecommunications services, primarily to small and medium-sized
businesses, carriers and resellers. The Company operates a pan-European
communication network with international gateway switching centers in New York
and London and network points of presence throughout Western Europe. The Company
is constructing a fiber optic ring which will connect five European countries
(the "Circe Network").
 
    (B) PRINCIPLES OF CONSOLIDATION
 
    The consolidated financial statements include the accounts of the Company
and its wholly owned subsidiaries. All significant inter-company balances and
transactions have been eliminated in consolidation. Investments in affiliates in
which the Company has significant influence but does not exercise control are
accounted for under the equity method.
 
    (C) CASH AND CASH EQUIVALENTS
 
    The Company's policy is to maintain its uninvested cash at minimum levels.
Unrestricted cash equivalents, which include highly liquid debt instruments
purchased with a maturity of three months or less, were $8.2 million and $278.9
million at December 31, 1997 and 1998, respectively.
 
    (D) REVENUE
 
    The Company records communication services revenue as earned, at the time
services are provided. Network capacity sales are recorded at the time the
capacity is provided to the customer.
 
    (E) PROPERTY AND EQUIPMENT
 
    Property and equipment consist principally of telecommunications related
equipment such as switches, fiber optic cable systems, remote nodes and related
computer software and is stated at cost. Assets acquired under capital leases
are stated at the present value of the future minimum lease payments.
Maintenance and repairs are expensed as incurred.
 
    Depreciation is provided using the straight-line method over the estimated
useful lives of the related assets. Leasehold improvements are amortized over
the life of the lease or useful life of the improvement, whichever is shorter.
The estimated useful lives are as follows:
 
<TABLE>
<S>                                                            <C>
Communications systems.......................................  5 to 7 years
Fiber optic cable systems....................................  15 years
Leasehold improvements.......................................  2 to 5 years
Furniture, equipment and other...............................  5 years
</TABLE>
 
    (F) INTANGIBLE ASSETS
 
    Deferred financing and registration fees represent costs incurred to issue
and register debt and are being amortized over the term of the related debt.
 
                                      F-8
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                        DECEMBER 31, 1996, 1997 AND 1998
 
(1) SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
    Licenses issued by governing bodies are being amortized over the lesser of
25 years or the term of the license.
 
    Goodwill, which represents the excess of purchase price over fair value of
net assets acquired, is amortized on a straight-line basis over the expected
periods to be benefitted, five to seven years.
 
    Acquired employee base and sales force in place represents the intangible
assets associated with the acquisition of independent sales organizations and is
being amortized over three years.
 
    The costs of all other intangible assets are being amortized over their
useful lives, ranging from three to seven years.
 
    (G) INCOME TAXES
 
    Deferred tax assets and liabilities are recognized for the future tax
consequences attributable to differences between the financial statement
carrying amounts of existing assets and liabilities and their respective tax
bases and operating loss and tax credit carryforwards. Deferred tax assets and
liabilities are measured using enacted tax rates expected to apply to taxable
income in the years in which those temporary differences are expected to be
recovered or settled. The effect on deferred tax assets and liabilities of a
change in tax rates is recognized in income or expense in the period it occurs.
 
    (H) FOREIGN CURRENCY TRANSLATION
 
    Foreign currency assets and liabilities are translated using the exchange
rates in effect at the balance sheet date. Results of operations are translated
using the average exchange rates prevailing throughout the year. The effects of
exchange rate fluctuations on translating foreign currency assets and
liabilities into U.S. dollars are accumulated as part of the foreign currency
translation adjustment in stockholders' equity. Gains and losses from foreign
currency transactions are included in selling, general and administrative
expenses in the period in which they occur. For the years ending December 31,
1996, 1997 and 1998, the Company experienced no material exchange transaction
gains or losses.
 
    (I) NET LOSS PER SHARE
 
    Basic earnings per share ("EPS") is computed by dividing income or loss
attributable to common stockholders by the weighted average number of common
shares outstanding for the period. Diluted EPS reflects the potential dilution
from the exercise or conversion of securities into common stock.
 
    Net loss and weighted average shares outstanding used for computing diluted
loss per common share were the same as that used for computing basic loss per
common share for each of the years ended December 31, 1996, 1997 and 1998.
 
    The Company had potentially dilutive common stock equivalents of 1.0
million, 1.1 million and 7.2 million for the years ended December 31, 1996, 1997
and 1998, respectively. These common stock equivalents were not included in the
computation of diluted net loss per common share because they were antidilutive
for the periods presented.
 
    (J) CONCENTRATION OF CREDIT RISK
 
    Financial instruments that potentially subject the Company to concentration
of credit risk consist primarily of temporary cash investments and trade
receivables. The Company restricts investment of
 
                                      F-9
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                        DECEMBER 31, 1996, 1997 AND 1998
 
(1) SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
temporary cash investments to financial institutions with high credit standing.
The Company does not believe there is any concentration of credit risk on trade
receivables as a result of the large and diverse nature of the Company's
worldwide customer base.
 
    During 1998, one customer, LD Exchange.com, accounted for 10.6% of the
Company's revenues.
 
    (K) RECLASSIFICATIONS
 
    Certain reclassifications have been made to the prior years' financial
statements to conform to the current year's presentation.
 
    (L) 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
disclosure of contingent assets and liabilities at the date of the financial
statements and the reported amounts of revenue and expenses during the reporting
period. Actual results could differ from those estimates.
 
    (M) ADDITIONAL ACCOUNTING POLICIES
 
    Additional accounting policies are incorporated into the notes herein.
 
    (N) STOCK OPTION PLAN
 
    The Company accounts for its stock option plan in accordance with Statement
of Financial Accounting Standards ("SFAS") No. 123 which allows entities to
continue to apply the provisions of Accounting Principles Board ("APB") Opinion
No. 25 and provide pro forma net income and pro forma earnings per share
disclosures for employee stock option grants made in 1995 and future years as if
the fair-value-based method, as defined in SFAS No. 123, had been applied. The
Company has elected to apply the provisions of APB Opinion No. 25 and provide
the pro forma disclosure required by SFAS No. 123. See Note 12.
 
    (O) IMPAIRMENT OF LONG-LIVED ASSETS AND LONG-LIVED ASSETS TO BE DISPOSED OF
 
    Long-lived assets and certain identifiable intangibles are reviewed for
impairment whenever events or changes in circumstances indicate that the
carrying amount of an asset may not be recoverable. Recoverability of assets to
be held and used is measured by a comparison of the carrying amount of an asset
to future net cash flows expected to be generated by the asset. If such assets
are considered to be impaired, the impairment to be recognized is measured by
the amount by which the carrying amount of the assets exceed the fair value of
the assets. Assets to be disposed of are reported at the lower of the carrying
amount or fair value less costs to sell.
 
(2) INVESTMENTS IN DEBT SECURITIES
 
    Management determines the appropriate classification of its investments in
debt securities at the time of purchase and classifies them as held to maturity
or available for sale. These investments are diversified among high credit
quality securities in accordance with the Company's investment policy. Debt
securities
 
                                      F-10
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                        DECEMBER 31, 1996, 1997 AND 1998
 
(2) INVESTMENTS IN DEBT SECURITIES (CONTINUED)
that the Company has both the intent and ability to hold to maturity are carried
at amortized cost. Debt securities for which the Company does not have the
intent or ability to hold to maturity are classified as available for sale.
Securities available for sale are carried at fair value, with the unrealized
gains and losses, net of tax, reported in a separate component of stockholders'
equity. The Company does not invest in securities for the purpose of trading and
as such does not classify any securities as trading.
 
    The cost of debt securities classified as held to maturity are adjusted for
amortization of premiums and accretion of discounts to maturity over the
estimated life of the security. Such amortization and accretion are included in
interest income. There were no securities classified as held to maturity as of
December 31, 1997 and no securities classified as available for sale as of
December 31, 1998.
 
    The following is a summary of the amortized cost, which approximates fair
value of restricted securities held to maturity at December 31, 1998 (in
thousands):
 
<TABLE>
<S>                                                                 <C>
U.S. Treasury obligations.........................................  $ 105,508
German government obligations.....................................     28,705
                                                                    ---------
    Total.........................................................  $ 134,213
                                                                    ---------
                                                                    ---------
</TABLE>
 
    The following is a summary of the amortized cost, which approximates fair
value of securities held to maturity at December 31, 1998 (in thousands):
 
<TABLE>
<S>                                                                 <C>
European corporate debt securities................................  $ 122,299
U.S. corporate debt securities....................................     49,472
                                                                    ---------
    Total.........................................................  $ 171,771
                                                                    ---------
                                                                    ---------
</TABLE>
 
    The following is a summary of the fair value of securities available for
sale at December 31, 1997 (in thousands):
 
<TABLE>
<S>                                                                  <C>
U.S. Treasury obligations..........................................  $   2,028
Corporate debt securities..........................................     13,482
Federal agencies obligations.......................................     10,537
                                                                     ---------
    Total..........................................................  $  26,047
                                                                     ---------
                                                                     ---------
</TABLE>
 
    Unrealized gains or losses on securities classified as available for sale
are not material at December 31, 1997.
 
    The amortized cost, which approximates fair value, of restricted securities
held to maturity at December 31, 1998 are shown below (in thousands):
 
<TABLE>
<S>                                                                 <C>
Due within one year...............................................  $  50,870
Due after one year through two years..............................     54,328
Due after two years...............................................     29,015
                                                                    ---------
    Total.........................................................  $ 134,213
                                                                    ---------
                                                                    ---------
</TABLE>
 
                                      F-11
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                        DECEMBER 31, 1996, 1997 AND 1998
 
(2) INVESTMENTS IN DEBT SECURITIES (CONTINUED)
    There were no changes in the classification of any securities held to
maturity or securities available for sale from the time of purchase to the time
of maturity or sale.
 
(3) PROPERTY AND EQUIPMENT
 
    Property and equipment consists of the following as of December 31 (in
thousands):
 
<TABLE>
<CAPTION>
                                                                                               1997        1998
                                                                                            ----------  ----------
<S>                                                                                         <C>         <C>
Communications system.....................................................................  $   43,322  $   70,971
Construction in progress..................................................................      10,094     172,630
Fiber optic cable systems.................................................................       1,432      25,222
Furniture, equipment and other............................................................       8,924      16,450
Leasehold improvements....................................................................       3,254       6,651
                                                                                            ----------  ----------
                                                                                                67,026     291,924
Less accumulated depreciation and amortization............................................      12,932      25,668
                                                                                            ----------  ----------
                                                                                            $   54,094  $  266,256
                                                                                            ----------  ----------
                                                                                            ----------  ----------
</TABLE>
 
    At December 31, 1997, construction in progress represents a portion of the
expansion of the Company's European network. At December 31, 1998, construction
in progress represents construction of the Circe Network. For the years ended
December 31, 1996, 1997 and 1998, $0.1 million, $0.2 million and $3.3 million of
interest was capitalized.
 
    The Company trades indefeasible rights-of-use or capacity on the Circe
Network for indefeasible rights-of-use or capacity on other cable systems. These
trades of indefeasible rights-of-use or capacity are accounted for as
non-monetary exchanges and did not have a material effect on the Company's
statement of operations.
 
    At December 31, 1998, the Company has entered into a letter of intent with
Metromedia Fiber Networks, Inc. and Carrier 1, Inc. to jointly construct the
civil works associated with a national communications networks being constructed
by each party in Germany. As part of the letter of intent, Metromedia Fiber
Networks, Inc. and Carrier 1, Inc. were required to place in escrow with the
Company an amount of $9.3 million which is included in restricted cash
equivalents in the accompanying consolidated balance sheets. In February 1999,
the parties entered into a definitive agreement which required each party to
supply a standby letter of credit to cover the construction costs related to
their portion of the network.
 
                                      F-12
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                        DECEMBER 31, 1996, 1997 AND 1998
 
(4) INTANGIBLE ASSETS
 
    Intangible assets consist of the following as of December 31 (in thousands):
 
<TABLE>
<CAPTION>
                                                                                                1997       1998
                                                                                              ---------  ---------
<S>                                                                                           <C>        <C>
Deferred financing and registration costs...................................................  $   3,789  $  31,547
Licenses, trademarks and servicemarks.......................................................        464     10,031
Goodwill....................................................................................        474      8,744
Purchased software..........................................................................      1,494      1,859
Acquired employee base and sales force in place.............................................      1,607     --
Other.......................................................................................        385        206
                                                                                              ---------  ---------
                                                                                                  8,213     52,387
Less accumulated amortization...............................................................      3,875      5,419
                                                                                              ---------  ---------
                                                                                              $   4,338  $  46,968
                                                                                              ---------  ---------
                                                                                              ---------  ---------
</TABLE>
 
(5) ACCOUNTS PAYABLE AND ACCRUED EXPENSES
 
    Accounts payable and accrued expenses consists of the following as of
December 31 (in thousands):
 
<TABLE>
<CAPTION>
                                                                                                1997       1998
                                                                                              ---------  ---------
<S>                                                                                           <C>        <C>
Accounts payable............................................................................  $   6,231  $   5,566
Accrued expenses............................................................................      3,253     16,224
Accrued compensation and benefits...........................................................      1,269      1,866
                                                                                              ---------  ---------
                                                                                              $  10,753  $  23,656
                                                                                              ---------  ---------
                                                                                              ---------  ---------
</TABLE>
 
(6) LINE OF CREDIT AND LETTERS OF CREDIT
 
    The Company has a revolving line of credit agreement which provides for
secured borrowings of up to $11.2 million. Borrowings under this line of credit
agreement can be made under either of the following interest rate formulas: (i)
the lending institution's prime rate or (ii) the LIBOR rate plus two hundred
basis points. The Company had $0.6 million in borrowings under the line of
credit agreement at December 31, 1997 and no borrowings under the line of credit
agreement at December 31, 1998. The terms of the line of credit agreement
include, among other provisions, requirements for maintaining defined levels of
securities and other liquid collateral. At December 31, 1998, standby letters of
credit of approximately $3.3 million have been issued under this line of credit
agreement.
 
    In connection with the Company's joint construction of the civil works
associated with national communications networks being constructed by each party
in Germany, in February 1999 the Company was required to obtain a letter of
credit of approximately $123 million (DM219.1 million) in support of its
obligations.
 
    The weighted-average interest rate on short-term borrowings under the line
of credit agreement at December 31, 1997 was 8.0%.
 
                                      F-13
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                        DECEMBER 31, 1996, 1997 AND 1998
 
(7) LONG TERM LIABILITIES AND REDEEMABLE CONVERTIBLE PREFERRED STOCK
 
    (A) LONG TERM DEBT AND REDEEMABLE CONVERTIBLE PREFERRED STOCK
 
    On April 8, 1998, the Company completed an offering of units (the "Units
Offering") consisting of senior notes or senior discount notes due 2008 and
shares of 10% Series A Redeemable Convertible Preferred Stock due 2010 ("Series
A Preferred"), $.01 par value per share, of the Company and units consisting of
senior notes or senior discount notes due 2008 and subordinated convertible
debentures due 2011 (the "Subordinated Debentures") through which it raised
approximately $889.6 million of gross proceeds ($856.6 million of net proceeds).
The Company utilized $118.9 million of the proceeds from the Units Offering to
retire its 15% Senior Discount Notes due 2005 resulting in an extraordinary loss
of $28.3 million. Additionally, a portion of the proceeds from the Units
Offering were used to purchase approximately $122.8 million of U.S. government
securities which were pledged as security for the first six interest payments on
the U.S. dollar denominated senior notes and approximately $30.6 million of
German government obligations which were pledged as security for the first six
interest payments on the Deutsche Mark denominated senior notes issued in the
Units Offering. The senior discount notes accrete through April 15, 2003 and
interest becomes payable in cash in semi-annual installments thereafter. The
interest on the senior notes is payable in semi-annual installments. The Series
A Preferred and the subordinated convertible debentures require quarterly
payments which are paid in additional securities, cash or any combination
thereof through April 15, 2003 and payable in cash thereafter. The Series A
Preferred and the subordinated convertible debentures are mandatorily
convertible in the event the closing price of the Company's common stock exceeds
certain predetermined annual price targets. The Series A Preferred and the
Subordinated Debentures conversion rates are $13.20 and DM24.473 ($14.58),
respectively. In addition, the terms of the Series A Preferred and Subordinated
Debentures provide for special dividends and special interest payments,
respectively, under certain conditions.
 
    The indentures pursuant to which the senior notes and the senior discount
notes were issued contain certain covenants that, among other things, limit the
ability of the Company to incur additional indebtedness, pay dividends or make
certain other distributions, enter into transactions with stockholders and
affiliates and create liens on its assets. In addition, upon a change of
control, the Company is required to make an offer to purchase the senior notes
and the senior discount notes at a purchase price equal to 101% of the principal
amount, in the case of the senior notes, and 101% of the accreted value of the
notes, in the case of the senior discount notes. The indenture pursuant to which
the subordinated convertible debentures were issued also requires that the
Company offer to repurchase the debentures at 101% of the principal amount in
the event of a change of control.
 
    On September 30, 1998, the Company consummated an offer to exchange senior
notes and senior discount notes due 2008 which have been registered under the
Securities Act of 1933, as amended, for outstanding notes of each such series
which were not registered under the Securities Act of 1933, as amended.
 
                                      F-14
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                        DECEMBER 31, 1996, 1997 AND 1998
 
(7) LONG TERM LIABILITIES AND REDEEMABLE CONVERTIBLE PREFERRED STOCK (CONTINUED)
    Long term debt consists of the following as of December 31 (in thousands):
 
<TABLE>
<CAPTION>
                                                                                               1997        1998
                                                                                             ---------  ----------
<S>                                                                                          <C>        <C>
11.25% Senior Notes........................................................................  $  --      $  400,000
11.15% Senior Notes (DM178,000)............................................................     --         106,015
12.50% Senior Discount Notes, less discount of $202,716....................................     --         297,284
12.40% Senior Discount Notes (DM134,916), less discount of $54,249
  (DM91,084)...............................................................................     --          80,355
10% Subordinated Convertible Debentures (DM21,573).........................................     --          12,849
15% Senior Discount Notes, less discount of $30,845........................................     89,855      --
                                                                                             ---------  ----------
                                                                                             $  89,855  $  896,503
                                                                                             ---------  ----------
                                                                                             ---------  ----------
</TABLE>
 
    (B) EQUIPMENT FINANCING
 
    In November and December 1997, the Company entered into Loan and Security
Agreements, as amended, with Charter Financial, Inc. ("Charter") pursuant to
which the Company borrowed an aggregate of $11.1 million, of which $7.8 million
was outstanding as of December 31, 1998. Repayment of these loans commenced in
December 1997 and January 1998 and are repayable in thirty-two or thirty-six
successive monthly installments respectively. Under the terms of these
arrangements, the Company is required to satisfy certain EBITDA and unrestricted
cash requirements. As of December 31, 1998, the Company was either in compliance
with, or had received waivers to, these covenants. Obligations under these Loan
and Security Agreements are secured by the grant to Charter of a security
interest in certain designated telecommunications equipment. A portion of the
payment obligations under these borrowing arrangements are also secured by
letters of credit.
 
(8) STOCKHOLDERS' EQUITY
 
    On October 23, 1996, the Company completed an initial public offering
("IPO") of its Common Stock, through which it sold 8,667,000 shares of Common
Stock at $12 a share and raised approximately $104 million of gross proceeds
($94.5 million of net proceeds).
 
    In connection with the IPO, all shares of then Class A Common Stock were
converted into shares of Common Stock at a ratio of one-to-one and all then
outstanding shares of Common Stock were subject to a reverse stock split at a
ratio of 3-to-2. In addition, the Company's stockholders approved an amendment
to the Company's Certificate of Incorporation which (i) authorized the Board of
Directors to issue up to two million shares of Preferred Stock, $.01 par value
per share, of which no shares were issued and outstanding at December 31, 1996,
in one or more series and to fix the powers, voting rights, designations and
preferences of each series and (ii) eliminated the Class A Common Stock.
 
    All earnings per share and share data presented herein reflect the
conversion of the Class A Common Stock into Common Stock and the reverse stock
split of all then outstanding shares of Common Stock.
 
(9) ACQUISITION
 
    On February 27, 1998, the Company acquired Flat Rate Communications, Inc.
("Flat Rate"), a long distance telecommunications reseller, for $5.0 million of
cash, 375,000 shares of Common Stock and a contingent payment based upon key
operating performance targets for the twelve month period ending February 28,
1999 which will range from zero to $21.0 million in cash and zero to 1.0 million
shares of
 
                                      F-15
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                        DECEMBER 31, 1996, 1997 AND 1998
 
(9) ACQUISITION (CONTINUED)
Common Stock. The Company recorded the acquisition under the purchase method of
accounting. The purchase price has been allocated to the assets acquired and
liabilities assumed, based upon the estimated fair values at the date of
acquisition. The excess purchase price was $8.3 million and will be amortized on
a straight line basis over a five-year period. If the acquisition had occurred
on January 1, 1996 (i) communication services revenue for the years 1996, 1997
and 1998 would have been $53.4 million, $101.8 million and $138.5 million,
respectively, (ii) loss before extraordinary loss for 1998 would have been
$(98.9) million, (iii) net loss attributable to common stockholders for the
years 1996, 1997 and 1998 would have been $(38.5) million, $(42.8) million and
$(130.5) million, respectively and (iv) net loss per common share for the years
1996, 1997 and 1998 would have been $(2.43), $(1.86) and $(5.65), respectively.
 
(10) INCOME TAXES
 
    The statutory Federal tax rates for the years ended December 31, 1996, 1997
and 1998 were 35%. The effective tax rates were zero for the years ended
December 31, 1996, 1997 and 1998 due to the Company incurring net operating
losses for which no tax benefit was recorded.
 
    For Federal and foreign income tax purposes, the Company has unused net
operating loss carryforwards of approximately $218.8 million expiring in 2007
through 2018. The availability of the net operating loss carryforwards to offset
income in future years is restricted as a result of the Company's issuance of
its Common Stock and may be further restricted as a result of future sales of
Company stock and other events.
 
    The tax effect of temporary differences that give rise to significant
portions of the deferred tax assets are as follows (in thousands):
 
<TABLE>
<CAPTION>
                                                                             DECEMBER 31,
                                                                        ----------------------
<S>                                                                     <C>         <C>
                                                                           1997        1998
                                                                        ----------  ----------
Accounts receivable principally due to
  allowance for doubtful accounts.....................................  $      587  $    1,506
OID Interest not deductible in current period.........................      11,149      11,125
Federal net operating loss carryforwards..............................      29,093      68,579
Foreign net operating loss carryforwards..............................       3,777       7,989
                                                                        ----------  ----------
      Total gross deferred tax assets.................................      44,606      89,199
Less valuation allowance..............................................     (44,606)    (89,199)
                                                                        ----------  ----------
      Net deferred tax assets.........................................  $   --      $   --
                                                                        ----------  ----------
                                                                        ----------  ----------
</TABLE>
 
    In assessing the realizability of deferred tax assets, management considers
whether it is more likely than not that some portion or all of the deferred tax
assets will not be realized. The ultimate realization of deferred tax assets is
dependent upon the generation of future taxable income during the periods in
which those temporary differences become deductible. Management considers the
scheduled reversal of deferred tax liabilities, projected future taxable income,
and tax planning in making these assessments. During 1997 and 1998, the
valuation allowance increased by $14.7 million and $44.6 million, respectively.
 
(11) SEGMENT AND GEOGRAPHIC DATA
 
    All of the Company's operations are in a single industry segment,
communications services. While the Company's chief decision maker monitors the
revenue streams of the various products and geographic locations, operations are
managed and financial performance is evaluated based on the delivery of
 
                                      F-16
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                        DECEMBER 31, 1996, 1997 AND 1998
 
(11) SEGMENT AND GEOGRAPHIC DATA (CONTINUED)
multiple, integrated services to customers over a single network. As a result,
there are many shared expenses generated by the various revenue streams and
management believes that any allocation of the expenses incurred to multiple
revenue streams or geographic locations would be impractical and arbitrary.
Management does not currently make such allocations internally.
 
    The Company groups its products and services by two customers types,
wholesale and retail. The information below summarizes communication services
revenue by customer type (in thousands):
 
<TABLE>
<CAPTION>
                                                                                    1996       1997        1998
                                                                                  ---------  ---------  ----------
<S>                                                                               <C>        <C>        <C>
Wholesale.......................................................................  $   9,516  $  20,397  $   78,777
Retail..........................................................................     40,903     52,621      56,411
                                                                                  ---------  ---------  ----------
Consolidated....................................................................  $  50,419  $  73,018  $  135,188
                                                                                  ---------  ---------  ----------
                                                                                  ---------  ---------  ----------
</TABLE>
 
    The information below summarizes communication services revenue by
geographic area (in thousands):
 
<TABLE>
<CAPTION>
                                                                                    1996       1997        1998
                                                                                 ----------  ---------  ----------
<S>                                                                              <C>         <C>        <C>
Western Europe.................................................................  $   19,917  $  32,647  $   62,946
North America..................................................................       9,516     15,936      56,172
Latin America..................................................................      14,402     16,240      14,653
Asia/Pacific Rim and other.....................................................       6,584      8,195       1,417
                                                                                 ----------  ---------  ----------
  Consolidated.................................................................  $   50,419  $  73,018  $  135,188
                                                                                 ----------  ---------  ----------
                                                                                 ----------  ---------  ----------
</TABLE>
 
    The information below summarizes long lived assets by geographic area (in
thousands):
 
<TABLE>
<CAPTION>
                                                                                               1997        1998
                                                                                             ---------  ----------
<S>                                                                                          <C>        <C>
Western Europe.............................................................................  $  32,640  $  237,443
North America..............................................................................     25,626      75,492
Latin America..............................................................................        166         289
                                                                                             ---------  ----------
Consolidated...............................................................................  $  58,432  $  313,224
                                                                                             ---------  ----------
                                                                                             ---------  ----------
</TABLE>
 
(12) STOCK OPTION PLAN
 
    During 1993, the Board of Directors approved the 1993 Flexible Stock
Incentive Plan, as amended (the "Stock Incentive Plan") under which
"non-qualified" stock options ("NQSOs") to acquire shares of Common Stock may be
granted to employees, directors and consultants of the Company and "incentive"
stock options ("ISOs") to acquire shares of Common Stock may be granted to
employees, including non-employee directors. The Stock Incentive Plan also
provides for the grant of stock appreciation rights ("SARs") and shares of
restricted stock to the Company's employees, directors and consultants.
 
    The Stock Incentive Plan provides for the issuance of up to a maximum of
4,166,666 shares of Common Stock and is currently administered by the
Compensation Committee of the Board of Directors. Under the Stock Incentive
Plan, the option price of any ISO may not be less than the fair market value of
a share of Common Stock on the date on which the option is granted. The option
price of an NQSO may be less than the fair market value on the date the NQSO is
granted if the Board of Directors so determines. An ISO may not be granted to a
"ten percent stockholder" (as such term is defined in Section 422A of the
Internal Revenue Code) unless the exercise price is at least 110% of the fair
market value of the Common
 
                                      F-17
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                        DECEMBER 31, 1996, 1997 AND 1998
 
(12) STOCK OPTION PLAN (CONTINUED)
Stock and the term of the option may not exceed five years from the date of
grant. Common Stock subject to a restricted stock purchase or bonus agreement is
transferable only as provided in such agreement. The maximum term of each stock
option granted to persons other than ten percent stockholders is ten years from
the date of grant.
 
    The per share weighted average fair value of stock options granted during
1996, 1997 and 1998 was $2.29, $5.99 and $6.40, respectively, on the date of
grant using the Black-Scholes option pricing model with the following
assumptions: (1) a risk free interest rate of 5.5% in 1996 and 1997 and 5.0% in
1998, (2) an expected life of 10 years for all years, (3) volatility of
approximately 35.9% for 1996, 52.2% for 1997 and 92.7% for 1998 and (4) an
annual dividend yield of 0% for all years.
 
    The Company applies the provisions of APB Opinion No. 25 in accounting for
its Stock Incentive Plan and, accordingly, no compensation cost has been
recognized for its stock options in the financial statements since the exercise
price was equal to or greater than the fair market value at the date of grant.
Had the Company determined compensation cost based on the fair value at the
grant date for its stock options under SFAS No. 123, the Company's net loss
would have been increased to the pro forma amounts indicated below:
 
<TABLE>
<CAPTION>
                                                              1996        1997        1998
                                                           ----------  ----------  -----------
<S>                                                        <C>         <C>         <C>
Net loss, as reported (in thousands).....................  $  (38,375) $  (43,044) $  (130,605)
Net loss, pro forma (in thousands).......................     (38,986)    (44,171)    (135,458)
Net loss per common share, as reported...................       (2.47)      (1.90)       (5.67)
Net loss per common share, pro forma.....................       (2.51)      (1.95)       (5.88)
</TABLE>
 
    Pro forma net loss reflects only options granted since January 1, 1995.
Therefore, the full impact of calculating compensation cost for stock options
under SFAS No. 123 is not reflected in the pro forma net loss amounts because
compensation cost is reflected over the options' vesting period of three years
and compensation cost for options granted prior to January 1, 1995 is not
considered.
 
                                      F-18
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                        DECEMBER 31, 1996, 1997 AND 1998
 
(12) STOCK OPTION PLAN (CONTINUED)
    Stock option activity under the Stock Incentive Plan is shown below:
 
<TABLE>
<CAPTION>
                                                                                           WEIGHTED
                                                                                            AVERAGE       NUMBER OF
                                                                                           EXERCISE        SHARES
                                                                                            PRICES     (IN THOUSANDS)
                                                                                          -----------  ---------------
<S>                                                                                       <C>          <C>
Outstanding at January 1, 1996..........................................................        4.01            474
Granted.................................................................................        6.75            823
Forfeited...............................................................................        5.77           (188)
Exercised...............................................................................        2.70           (139)
                                                                                               -----         ------
Outstanding at December 31, 1996........................................................        6.18            970
Granted.................................................................................        8.61            428
Forfeited...............................................................................        6.68           (197)
Expired.................................................................................        5.46            (27)
Exercised...............................................................................        3.49           (122)
                                                                                               -----         ------
Outstanding at December 31, 1997........................................................        7.40          1,052
Granted.................................................................................        7.19          1,794
Forfeited...............................................................................        7.14            (64)
Expired.................................................................................        5.05            (14)
Exercised...............................................................................        5.44           (174)
                                                                                               -----         ------
Outstanding at December 31, 1998........................................................        7.41          2,594
                                                                                               -----         ------
                                                                                               -----         ------
</TABLE>
 
    The following table summarizes weighted-average option exercise price
information:
 
<TABLE>
<CAPTION>
                                            OPTIONS OUTSTANDING                    OPTIONS EXERCISABLE
                                  ----------------------------------------  ----------------------------------
<S>                               <C>              <C>         <C>          <C>                    <C>
                                      NUMBER
                                  OUTSTANDING AT    WEIGHTED    WEIGHTED           NUMBER           WEIGHTED
            RANGE OF               DECEMBER 31,     AVERAGE      AVERAGE       EXERCISABLE AT        AVERAGE
            EXERCISE                   1998        REMAINING    EXERCISE      DECEMBER 31, 1998     EXERCISE
             PRICES               (IN THOUSANDS)      LIFE        PRICE        (IN THOUSANDS)         PRICE
- --------------------------------  ---------------  ----------  -----------  ---------------------  -----------
         $0.75 - $3.50                       2      5 Years          0.75                 2              0.75
          3.51 - 5.75                      999      9 Years          5.22                19              3.74
          5.76 - 8.75                      552      8 Years          6.17               291              5.90
          8.76 - 12.00                   1,041      9 Years         10.13               148             10.22
                                         -----                      -----               ---             -----
                                         2,594                       7.41               460              7.18
                                         -----                      -----               ---             -----
                                         -----                      -----               ---             -----
</TABLE>
 
    Prior to the adoption of the Stock Incentive Plan, 5,913 options were
granted. These options were exercised at $0.75 per share during the year ended
December 31, 1996.
 
    The exercise price of all options approximates the fair market value of the
Common Stock on the date of grant.
 
    In addition, prior to the adoption of the Stock Incentive Plan, the Board of
Directors authorized the issuance of up to 233,333 shares of Common Stock as
compensation to employees and consultants of the Company of which 219,639 are
available for issuance at December 31, 1998.
 
                                      F-19
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                        DECEMBER 31, 1996, 1997 AND 1998
 
(13) COMMITMENTS AND CONTINGENCIES
 
    (A) LEASES
 
    At December 31, 1998, the Company was committed under non-cancelable
operating and capital leases for the rental of office space, network locations
and for fiber optic cable systems.
 
    The Company's future minimum capital and operating lease payments are as
follows (in thousands):
 
<TABLE>
<CAPTION>
                                                                           CAPITAL    OPERATING
                                                                          ---------  -----------
<S>                                                                       <C>        <C>
1999....................................................................  $   6,890   $   3,917
2000....................................................................      6,952       4,277
2001....................................................................      4,372       4,206
2002....................................................................      1,635       4,263
2003....................................................................      1,635       4,231
Thereafter..............................................................     32,692      28,853
                                                                          ---------  -----------
                                                                             54,176   $  49,747
                                                                                     -----------
                                                                                     -----------
Less interest costs.....................................................     28,453
                                                                          ---------
                                                                          $  25,723
                                                                          ---------
                                                                          ---------
</TABLE>
 
    Total rent expense amounted to $1.5 million, $1.3 million and $1.8 million
for the years ended December 31, 1996, 1997 and 1998, respectively.
 
    (B) CARRIER CONTRACTS
 
    The Company has entered into contracts to purchase transmission capacity
from various domestic and foreign carriers. By committing to purchase minimum
volumes of transmission capacity from carriers, the Company is able to obtain
guaranteed rates which are more favorable than those generally offered in the
marketplace. The minimum volume commitments are approximately $13.2 million for
the year ending December 31, 1999. The Company is involved in disputes with
carriers arising in the ordinary course of business. The Company believes the
outcome of all current disputes will not have a material effect on the Company's
financial position or results of operations.
 
    (C) PURCHASE COMMITMENTS
 
    The Company is continually upgrading and expanding its network and its
switching facilities. In connection therewith, the Company has entered into
purchase commitments to expend approximately $38.2 million.
 
    The Company is developing a fiber-optic ring which will connect over 30
cities in Western Europe (the "Circe Network"). In connection with the Circe
Network, the Company has entered into purchase commitments to expend
approximately $130.6 million.
 
    (D) EMPLOYMENT CONTRACTS
 
    The Company has employment contracts with certain officers at amounts
generally equal to such officers' current levels of compensation. The Company's
remaining commitments at December 31, 1998 for the next three years under such
contracts aggregates approximately $1.4 million.
 
                                      F-20
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                        DECEMBER 31, 1996, 1997 AND 1998
 
(13) COMMITMENTS AND CONTINGENCIES (CONTINUED)
    (E) LITIGATION
 
    From time to time, the Company is subject to litigation in the normal course
of business. The Company believes that any adverse outcome from litigation would
not have a material adverse effect on its financial position or results of
operations.
 
(14) REGULATORY MATTERS
 
    The Company is subject to regulation in countries in which it does business.
The Company believes that an adverse determination as to the permissibility of
the Company's services under the laws and regulations of any such country would
not have a material adverse long-term effect on its business.
 
(15) RELATED PARTY TRANSACTIONS
 
    During 1998, the Company entered into an agreement with Cignal Global
Communications, Inc. ("Cignal"), pursuant to which the Company sold
transatlantic capacity. Consideration received was in the form of 650,000 shares
of Cignal's common stock. The Company recognized $3.25 million of revenue, the
fair value of the transatlantic capacity. In addition, the Company agreed to
sell capacity on the Circe Network in exchange for an additional 350,000 shares
of Cignal's common stock. Pending delivery of the capacity to Cignal, these
350,000 shares are being held in escrow. The Company's Chairman and Chief
Executive Officer is a director of Cignal.
 
    On June 3, 1998, the Company entered into a Mutual Cooperation Agreement
with Martin Varsavsky, a greater than ten percent stockholder of the Company,
and Jazz Telecom S.A. pursuant to which the parties made certain agreements
including the following: (1) subject to Jazz Telecom S.A. completing a high
yield offering with net proceeds to Jazz Telecom S.A. of at least $100 million
(the "Offering Condition"), the Company and Jazz Telecom S.A. agreed to use
commercially reasonable efforts to execute and deliver a construction agreement
no later than January 1, 1999 to construct a fiber optic submarine cable system
between Spain and the United Kingdom, (2) subject to the Offering Condition the
Company agreed to purchase $6.0 million of Jazz Telecom S.A. common stock, (3)
the Company and Jazz Telecom S.A. agreed to the purchase from the other
international switched minutes and to transmit at least one-third of our Spanish
domestic switched minute traffic over Jazz Telecom S.A.'s network, assuming the
prices charged by Jazz Telecom S. A. are competitive, (4) the Company and Jazz
Telecom S.A. agreed to sell capacity to each other for fixed prices, (5) Mr.
Varsavsky agreed to lock-up his Viatel shares for a specified period, (6) the
Company agreed to release any past claims which the Company had against either
Jazz Telecom S.A. and Mr. Varsavsky in exchange for their respective release of
any claims against the Company and (7) Mr. Varsavsky agreed to pay the Company
liquidated damages in the event that he violates certain provisions of the
agreement. The Company and Jazz Telecom S.A. are currently in discussions to
certain modifications to the terms of the Mutual Corporation Agreement.
 
    On November 13, 1998, Mr. Varsavsky entered into an additional lock-up
agreement with us pursuant to which Mr. Varsavsky agreed that he would not sell,
contract to sell, announce an intention to sell, pledge or otherwise dispose of
his shares of our common stock, either directly or indirectly, without the prior
written consent of the Company until after August 12, 1999.
 
                                      F-21
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
                      CONDENSED CONSOLIDATED BALANCE SHEET
 
                       (IN THOUSANDS, EXCEPT SHARE DATA)
 
<TABLE>
<CAPTION>
                                                                                                         MARCH 31,
                                                                                                            1999
                                                                                                        ------------
<S>                                                                                                     <C>
                                                                                                        (UNAUDITED)
                                                       ASSETS
Current assets:
  Cash and cash equivalents...........................................................................  $    442,042
  Restricted cash equivalents.........................................................................        23,530
  Restricted marketable securities, current...........................................................        90,430
  Marketable securities, current......................................................................        56,713
  Trade accounts receivable, less allowance for doubtful accounts of $2,966...........................        47,107
  Other receivables...................................................................................        14,463
  Prepaid expenses....................................................................................         8,512
                                                                                                        ------------
      Total current assets............................................................................       682,797
                                                                                                        ------------
Restricted marketable securities, non-current.........................................................       115,836
Property and equipment, net...........................................................................       409,909
Cash securing letters of credit for network construction..............................................       121,239
Intangible assets, net................................................................................        70,579
Other assets..........................................................................................        11,630
                                                                                                        ------------
                                                                                                        $  1,411,990
                                                                                                        ------------
                                                                                                        ------------
                                      LIABILITIES AND STOCKHOLDERS' DEFICIENCY
Current liabilities:
  Accrued telecommunications costs....................................................................  $     41,913
  Accounts payable and other accrued expenses.........................................................        25,379
  Property and equipment purchases payable............................................................       141,361
  Accrued interest....................................................................................        27,288
  Liability under joint construction agreement........................................................         9,631
  Current installments of notes payable and obligations under capital leases..........................        10,008
                                                                                                        ------------
      Total current liabilities.......................................................................       255,580
                                                                                                        ------------
Long-term liabilities:
  Long-term debt......................................................................................     1,256,196
  Notes payable and obligations under capital leases, excluding current installments..................        36,286
                                                                                                        ------------
      Total long-term liabilities.....................................................................     1,292,482
Series A Redeemable Convertible Preferred Stock, $.01 par value; authorized 718,042 shares; issued and
  outstanding 472,791.................................................................................        48,298
                                                                                                        ------------
Commitments and contingencies
Stockholders' deficiency:
  Preferred stock, $.01 par value. Authorized 1,281,958 shares, no shares issued and outstanding......            --
  Common stock, $.01 par value. Authorized 50,000,000 shares, issued and outstanding 23,193,265
    shares............................................................................................           232
  Additional paid-in capital..........................................................................       128,403
  Accumulated other comprehensive loss................................................................       (15,082)
  Accumulated deficit.................................................................................      (297,923)
                                                                                                        ------------
      Total stockholders' deficiency..................................................................      (184,370)
                                                                                                        ------------
                                                                                                        $  1,411,990
                                                                                                        ------------
                                                                                                        ------------
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                      F-22
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
                CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
 
                                  (UNAUDITED)
 
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
 
<TABLE>
<CAPTION>
                                                                                       FOR THE THREE MONTHS
                                                                                         ENDED MARCH 31,
                                                                                      ----------------------
<S>                                                                                   <C>         <C>
                                                                                         1998        1999
                                                                                      ----------  ----------
Revenue:
Communication service revenue.......................................................  $   21,239  $   48,395
Capacity sales......................................................................          --      13,246
                                                                                      ----------  ----------
      Total revenue.................................................................      21,239      61,641
                                                                                      ----------  ----------
Operating expenses:
  Cost of services and sales........................................................      19,105      51,048
  Selling, general and administrative...............................................       8,955      18,763
  Depreciation and amortization.....................................................       2,911       9,603
                                                                                      ----------  ----------
      Total operating expenses......................................................      30,971      79,414
                                                                                      ----------  ----------
Other income (expense):
  Interest income...................................................................         510       6,828
  Interest expense..................................................................      (3,781)    (26,166)
                                                                                      ----------  ----------
Net loss............................................................................     (13,003)    (37,111)
  Dividend on redeemable convertible preferred stock................................          --      (1,177)
                                                                                      ----------  ----------
Net loss attributable to common stockholders........................................  $  (13,003) $  (38,288)
                                                                                      ----------  ----------
                                                                                      ----------  ----------
Net loss per common share attributable to common stockholders.......................  $    (0.57) $    (1.65)
                                                                                      ----------  ----------
                                                                                      ----------  ----------
Weighted average common shares outstanding..........................................      22,783      23,186
                                                                                      ----------  ----------
                                                                                      ----------  ----------
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                      F-23
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
                CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
 
                                  (UNAUDITED)
                                 (IN THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                                            FOR THE THREE MONTHS
                                                                                               ENDED MARCH 31,
                                                                                           -----------------------
                                                                                              1998        1999
                                                                                           ----------  -----------
<S>                                                                                        <C>         <C>
Cash flows from operating activities:
  Net loss...............................................................................  $  (13,003) $   (37,111)
  Adjustments to reconcile net loss to net cash used in operating activities:
    Depreciation and amortization........................................................       2,911        9,603
    Accreted interest expense on long term debt..........................................       3,447       10,330
    Provision for losses on accounts receivable..........................................         754        1,600
    Earned compensation..................................................................          16           --
  Changes in assets and liabilities:
    Increase in accounts receivable......................................................      (2,732)     (18,936)
    Increase in accrued interest expense on senior notes.................................          --       15,049
    Increase in prepaid expenses and other receivables...................................      (1,248)      (8,855)
    Decrease (increase) in other assets and intangible assets............................         555         (947)
    Decrease (increase) in accrued telecommunication costs, accounts payable and other
      accrued expenses...................................................................      (1,471)       7,689
                                                                                           ----------  -----------
        Net cash used in operating activities............................................     (10,771)     (21,578)
                                                                                           ----------  -----------
Cash flows from investing activities:
  Purchase of property, equipment and software...........................................      (2,716)    (101,691)
  Payment for business acquired, excluding cash acquired.................................      (5,000)          --
  Purchase of marketable securities......................................................      (3,510)    (194,058)
  Cash securing letters of credit for network construction...............................          --     (121,239)
  Issuance of notes receivable...........................................................          --       (4,390)
  Proceeds from maturity of marketable securities........................................      27,681      220,954
                                                                                           ----------  -----------
        Net cash provided by (used in) investing activities..............................      16,455     (200,424)
                                                                                           ----------  -----------
                                                                                           ----------  -----------
Cash flows from financing activities:
  Proceeds from issuance of senior notes.................................................          --      365,471
  Deferred financing costs...............................................................          --      (12,880)
  Proceeds from issuance of common stock.................................................         421           46
  Repayment of notes payable and bank credit line........................................        (577)        (682)
  Payments under capital leases..........................................................         (53)        (300)
                                                                                           ----------  -----------
        Net cash (used in) provided by financing activities..............................        (209)     351,655
                                                                                           ----------  -----------
Effects of exchange rate changes on cash.................................................        (109)      (3,902)
                                                                                           ----------  -----------
Net increase in cash equivalents.........................................................       5,366      125,751
Cash and cash equivalents at beginning of period.........................................      21,096      339,821
                                                                                           ----------  -----------
Cash and cash equivalents at end of period...............................................  $   26,462  $   465,572
                                                                                           ----------  -----------
                                                                                           ----------  -----------
Supplemental disclosures of cash flow information:
  Interest paid..........................................................................  $      334  $       231
                                                                                           ----------  -----------
  Assets acquired under capital lease obligations........................................          --  $    13,550
                                                                                           ----------  -----------
                                                                                           ----------  -----------
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                      F-24
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
              NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS
 
             (INFORMATION AS OF MARCH 31, 1999 AND FOR THE PERIODS
                  ENDED MARCH 31, 1998 AND 1999 IS UNAUDITED)
 
 (1) DESCRIPTION OF BUSINESS
 
     Viatel Inc. and subsidiaries (collectively, the "Company") is a global
     integrated services provider of high quality, competitively priced, long
     distance communication and data services to end users, carriers and
     resellers. The Company operates one of Europe's largest pan-European
     networks with points of presence in 45 cities, direct sales forces in
     twelve Western European cities and an indirect sales force in more than 180
     locations in Western Europe. The Company is currently constructing a series
     of state-of-the art, high quality, high capacity rings utilizing the
     synchronous digital hierarchy standard for digital transmission which will
     connect major cities in six European countries (the "Circe Network").
 
 (2) BASIS OF PRESENTATION
 
     The consolidated financial statements as of March 31, 1999 and for the
     three month periods ended March 31, 1999 and 1998, respectively, have been
     prepared by the Company without audit, pursuant to the rules and
     regulations of the Securities and Exchange Commission. In the opinion of
     management, all adjustments (consisting of only normal recurring
     adjustments) necessary for a fair presentation of the consolidated
     financial position, results of operations and cash flows for each period
     presented have been made on a consistent basis. Certain information and
     footnote disclosures normally included in consolidated financial statements
     prepared in accordance with generally accepted accounting principles have
     been condensed or omitted pursuant to such rules and regulations although
     management believes that the disclosures herein are adequate to make the
     information presented not misleading. It is suggested that these financial
     statements be read in conjunction with the Company's annual consolidated
     financial statements. Operating results for the three months ended March
     31, 1999 may not be indicative of the results that may be expected for the
     full year.
 
    CAPACITY SALES
 
         Customers of the Company can purchase capacity on the Company's
     network. Revenues from the sale of network capacity are recognized in the
     period that the rights and obligations of ownership transfer to the
     purchaser.
 
         Cost of IRU sales in any period is determined based upon the ratio of
     total capacity sold and total anticipated capacity to be utilized
     multiplied by the related total costs of the relevant portion of the
     network.
 
    NEW PRONOUNCEMENTS
 
         The Company adopted Statement of Position 98-5 (SOP 98-5), "Reporting
     on the Costs of Start-Up Activities," issued by the American Institute of
     Certified Public Accountants, during the three months ended March 31, 1999.
     SOP 98-5 requires that certain start-up expenditures and organization costs
     previously capitalized must now be expensed. The adoption of this statement
     did not have material effect on our consolidated financial statements.
 
                                      F-25
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
        NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF MARCH 31, 1999 AND FOR THE PERIODS
                  ENDED MARCH 31, 1998 AND 1999 IS UNAUDITED)
 
 (3) INVESTMENTS IN DEBT SECURITIES
 
     Management determines the appropriate classification of its investments in
     debt securities at the time of purchase and classifies them as held to
     maturity or available for sale. These investments are diversified among
     high credit quality securities in accordance with the Company's investment
     policy. Debt securities that the Company has both the intent and ability to
     hold to maturity are carried at amortized cost. Debt securities for which
     the Company does not have the intent or ability to hold to maturity are
     classified as available for sale. Securities available for sale are carried
     at fair value, with the unrealized gains and losses, net of tax, reported
     in a separate component of stockholders' equity. The Company does not
     invest in securities for the purpose of trading and therefore does not
     classify any securities as trading.
 
     Debt securities classified as held to maturity are adjusted for
     amortization of premiums and accretion of discounts to maturity over the
     estimated life of the security. Such amortization and interest are included
     in interest income. There were no securities classified as available for
     sale as of March 31, 1999.
 
     The following is a summary of the amortized cost, which approximates fair
     value, of restricted securities held to maturity at March 31, 1999 (in
     thousands):
 
     The following is a summary of the amortized cost, which approximates fair
     value, of securities held to maturity at March 31, 1999 (in thousands):
 
<TABLE>
<S>                                                                  <C>
U.S. corporate debt securities.....................................  $  34,043
German corporate debt securities...................................     22,670
                                                                     ---------
  Total............................................................  $  56,713
                                                                     ---------
                                                                     ---------
</TABLE>
 
<TABLE>
<S>                                                                 <C>
U.S. Treasury obligations.........................................  $ 148,859
German government obligations.....................................     57,407
                                                                    ---------
  Total...........................................................  $ 206,266
                                                                    ---------
                                                                    ---------
</TABLE>
 
     The amortized cost, which approximates fair value, of restricted securities
     held to maturity at March 31, 1999 are shown below (in thousands):
 
<TABLE>
<S>                                                                 <C>
Due within one year...............................................  $  90,430
Due after one through two years...................................    115,836
                                                                    ---------
  Total...........................................................  $ 206,266
                                                                    ---------
                                                                    ---------
</TABLE>
 
     There were no changes in the classification of any securities held to
     maturity or securities available for sale from the time of purchase to the
     time of maturity or sale.
 
                                      F-26
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
        NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF MARCH 31, 1999 AND FOR THE PERIODS
                  ENDED MARCH 31, 1998 AND 1999 IS UNAUDITED)
 
 (4) PROPERTY AND EQUIPMENT
 
     Property and equipment consists of the following as of (in thousands):
 
<TABLE>
<CAPTION>
                                                                                    MARCH 31,
                                                                                       1999
                                                                                    ----------
<S>                                                                                 <C>
Communication system..............................................................  $  326,511
Construction in progress..........................................................      89,067
Furniture, equipment and other....................................................      17,742
Leasehold improvements............................................................       6,695
                                                                                    ----------
                                                                                       440,015
Less accumulated depreciation and amortization....................................      30,106
                                                                                    ----------
                                                                                    $  409,909
                                                                                    ----------
                                                                                    ----------
</TABLE>
 
     At March 31, 1999, construction in progress primarily represents
     construction of the Circe Network. For the three month periods ended March
     31, 1998 and 1999, $0 and $2.3 million of interest were capitalized,
     respectively.
 
    In connection with the Company's joint construction of the civil works
    associated with a national communications network being constructed in
    Germany, the Company was required to obtain a letter of credit of
    approximately $121.2 million (DM219.1 million) in support of its
    obligations.
 
 (5) INTANGIBLE ASSETS
 
     Intangible assets consist of the following as of (in thousands):
 
<TABLE>
<CAPTION>
                                                                                      MARCH 31,
                                                                                        1999
                                                                                     -----------
<S>                                                                                  <C>
Deferred financing and registration fees...........................................   $  44,427
Licenses, trademarks and servicemarks..............................................       9,464
Goodwill ..........................................................................      20,270
Purchased software.................................................................       3,096
Other..............................................................................         140
                                                                                     -----------
                                                                                         77,397
Less accumulated amortization......................................................       6,818
                                                                                     -----------
                                                                                      $  70,579
                                                                                     -----------
                                                                                     -----------
</TABLE>
 
    The Company recognized its obligation to pay contingent consideration for
    its 1998 acquisition of Flat Rate based upon key operating performance
    targets which were met during the period ended March 31, 1999. Such
    contingent consideration has been recorded as goodwill.
 
 (6) LONG TERM DEBT
 
     On April 8, 1998, the Company completed an offering of units (the "Units
     Offering") consisting of senior notes or senior discount notes due 2008 and
     shares of 10% Series A Redeemable Convertible
 
                                      F-27
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
        NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF MARCH 31, 1999 AND FOR THE PERIODS
                  ENDED MARCH 31, 1998 AND 1999 IS UNAUDITED)
 
 (6) LONG TERM DEBT (CONTINUED)
     Preferred Stock due 2010 ("Series A Preferred"), $.01 par value per share,
     of the Company and units consisting of senior notes or senior discount
     notes due 2008 and subordinated convertible debentures due 2011 (the
     "Subordinated Debentures") through which it raised approximately $889.6
     million of gross proceeds ($856.6 million of net proceeds). The Company
     utilized $118.9 million of the proceeds from the Units Offering to retire
     its 15% Senior Discount Notes due 2005 resulting in an extraordinary loss
     of $28.3 million. Additionally, a portion of the proceeds from the Units
     Offering were used to purchase approximately $122.8 million of U.S.
     government securities which were pledged as security for the first six
     interest payments on the U.S. dollar denominated senior notes and
     approximately $30.6 million of German government obligations which were
     pledged as security for the first six interest payments on the Deutsche
     Mark denominated senior notes issued in the Units Offering. The senior
     discount notes accrete through April 15, 2003 and interest becomes payable
     in cash in semi-annual installments thereafter. The Series A Preferred and
     the subordinated convertible debentures require quarterly payments which
     are paid in additional securities, cash or any combination thereof through
     April 15, 2003 and payable in cash thereafter. The Series A Preferred and
     the Subordinated Debentures are mandatorily convertible in the event the
     closing price of the Company's common stock exceeds certain predetermined
     annual price targets. On May 13, 1999, the conditions for mandatory
     conversion were met for both the Series A Preferred and the Subordinated
     Debentures. The Series A Preferred and Subordinated Debentures conversion
     rates are $13.20 and DM24.473, at the then applicable exchange rate,
     respectively.
 
     On September 30, 1998, the Company consummated an offer to exchange senior
     notes and senior discount notes due 2008 which have been registered under
     the Securities Act of 1933, as amended, for outstanding notes of each such
     series which were not registered under the Securities Act of 1933, as
     amended.
 
     On March 19, 1999, the Company completed a high yield offering through
     which it raised approximately $365.5 million of gross proceeds. A portion
     of the proceeds from this offering were used to purchase securities which
     were pledged as security for the first four interest payments on the notes
     issued.
 
     The indentures pursuant to which the senior notes and the senior discount
     notes were issued contain certain covenants that, among other things, limit
     the ability of the Company to incur additional indebtedness, pay dividends
     or make certain other distributions, enter into transactions with
     stockholders and affiliates and create liens on its assets. In addition,
     upon a change of control, the Company is required to make an offer to
     purchase the senior notes and the senior discount notes at a purchase price
     equal to 101% of the principal amount, in the case of the senior notes, and
     101% of the accreted value of the notes, in the case of the senior discount
     notes. The indenture pursuant to which the Subordinated Debentures were
     issued also required that the Company offer to repurchase the debentures at
     101% of the principal amount in the event of a change of control.
 
                                      F-28
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
        NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF MARCH 31, 1999 AND FOR THE PERIODS
                  ENDED MARCH 31, 1998 AND 1999 IS UNAUDITED)
 
 (6) LONG TERM DEBT (CONTINUED)
     Long term debt consists of the following as of (in thousands):
 
<TABLE>
<CAPTION>
                                                                                   MARCH 31,
                                                                                      1999
                                                                                  ------------
<S>                                                                               <C>
11.25% Senior Notes.............................................................  $    400,000
11.15% Senior Notes ([EURO]91,010)..............................................        98,389
11.50% Senior Notes.............................................................       200,000
11.50% Senior Notes ([EURO]150,000).............................................       162,162
12.50% Senior Discount Notes, less discount of $193,664.........................       306,336
12.40% Senior Discount Notes ([EURO]115,552), less discount of $48,093
  ([EURO]44,486)................................................................        76,828
10% Subordinated convertible debentures ([EURO]11,545)..........................        12,481
                                                                                  ------------
                                                                                  $  1,256,196
                                                                                  ------------
                                                                                  ------------
</TABLE>
 
     During 1997, the Company entered into Loan and Security Agreements pursuant
     to which the Company borrowed an aggregate of $11.1 million. Under the
     terms of these agreements, the Company is required to satisfy certain
     covenants and restrictions. As of March 31, 1999, the Company was either in
     compliance with, or had received waivers to, these covenants. Obligations
     under these Loan and Security Agreements are secured by the grant of a
     security interest in certain telecommunications equipment, as well as a
     portion of the payment obligations also being secured by letters of credit.
 
 (7) STOCK INCENTIVE PLAN
 
     The Amended Stock Incentive Plan (the "Stock Incentive Plan") provides for
     the issuance of up to a maximum of 4,166,666 shares of the Company's common
     stock.
 
     Stock option activity for the three months ended March 31, 1999 under the
     Stock Incentive Plan is shown below (number of shares in thousands):
 
<TABLE>
<CAPTION>
                                                                  WEIGHTED AVERAGE    NUMBER OF
                                                                   EXERCISE PRICES     SHARES
                                                                  -----------------  -----------
<S>                                                               <C>                <C>
Outstanding at December 31, 1998................................      $    7.41           2,594
Granted.........................................................          22.88             573
Exercised.......................................................           5.27              (9)
                                                                         ------      -----------
Outstanding at March 31, 1999...................................      $   10.22           3,158
                                                                         ------      -----------
                                                                         ------      -----------
</TABLE>
 
     As of March 31, 1999, 950,471 options were exercisable under the Stock
     Incentive Plan.
 
                                      F-29
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
        NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF MARCH 31, 1999 AND FOR THE PERIODS
                  ENDED MARCH 31, 1998 AND 1999 IS UNAUDITED)
 
(8) COMPREHENSIVE LOSS
 
    The Company's comprehensive loss is as follows (in thousands):
 
<TABLE>
<CAPTION>
                                                                         FOR THE THREE MONTHS
                                                                                ENDED
                                                                              MARCH 31,
                                                                        ----------------------
                                                                           1998        1999
                                                                        ----------  ----------
<S>                                                                     <C>         <C>
Net loss..............................................................  $  (13,003) $  (37,111)
Foreign currency translation adjustment...............................        (517)     (8,836)
                                                                        ----------  ----------
Comprehensive loss....................................................  $  (13,520) $  (45,947)
                                                                        ----------  ----------
                                                                        ----------  ----------
</TABLE>
 
(9) SEGMENT AND GEOGRAPHIC DATA
 
    Company's chief decision maker monitors revenue streams of the various
products and geographic locations, operations are managed and financial
performance is evaluated based on the delivery of multiple, integrated services
to customers over a single network. As a result, there are many shared expenses
generated by the various revenue streams and management believes that any
allocation of the expenses incurred to multiple revenue streams or geographic
locations would be impractical and arbitrary. Management does not currently make
such allocations internally.
 
     The Company groups its products and services by wholesale, retail, and
     capacity. The information below summarizes revenue by customer type for the
     three months ended March 31, 1998 and 1999, respectively (in thousands):
 
<TABLE>
<CAPTION>
                                                                               MARCH 31,
                                                                          --------------------
                                                                            1998       1999
                                                                          ---------  ---------
<S>                                                                       <C>        <C>
Wholesale...............................................................  $   9,477  $  21,061
Retail..................................................................     11,762     27,334
Capacity................................................................         --     13,246
                                                                          ---------  ---------
Consolidated............................................................  $  21,239  $  61,641
                                                                          ---------  ---------
                                                                          ---------  ---------
</TABLE>
 
     The information below summarizes revenue by geographic area for the three
     months ended March 31, 1998 and 1999, respectively (in thousands):
 
<TABLE>
<CAPTION>
                                                                               MARCH 31,
                                                                          --------------------
                                                                            1998       1999
                                                                          ---------  ---------
<S>                                                                       <C>        <C>
Western Europe..........................................................  $  11,228  $  41,449
North America...........................................................      5,707     17,252
Latin America...........................................................      3,694      2,897
Asia/Pacific Rim and other..............................................        610         43
                                                                          ---------  ---------
Consolidated............................................................  $  21,239  $  61,641
                                                                          ---------  ---------
                                                                          ---------  ---------
</TABLE>
 
                                      F-30
<PAGE>
                         VIATEL, INC. AND SUBSIDIARIES
 
        NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF MARCH 31, 1999 AND FOR THE PERIODS
                  ENDED MARCH 31, 1998 AND 1999 IS UNAUDITED)
 
(9) SEGMENT AND GEOGRAPHIC DATA (CONTINUED)
     The information below summarizes long lived assets by geographic area as of
     March 31, 1999 (in thousands):
 
<TABLE>
<CAPTION>
                                                                                    MARCH 31,
                                                                                       1999
                                                                                    ----------
<S>                                                                                 <C>
Western Europe....................................................................  $  381,712
North America.....................................................................      98,558
Latin America.....................................................................         218
                                                                                    ----------
Consolidated......................................................................  $  480,488
                                                                                    ----------
                                                                                    ----------
</TABLE>
 
(10) SUBSEQUENT EVENT--CONVERSION
 
     On May 13, 1999, the Series A Preferred Stock and its Subordinated
     Debentures converted into shares of the Company's common stock. The
     conversion was based upon maintenance of the Company's stock price above a
     certain per share price for a specified time period. The Preferred Stock
     and the Subordinated Debentures converted at a conversion price equal to
     $13.20 and DM24.473, at the then applicable exchange rate, respectively.
     Accordingly, the Company will issue approximately 4.6 million shares of
     common stock and will pay cash for any fractional shares due upon
     conversion, which is deemed to be immaterial.
 
                                      F-31
<PAGE>
                                 [VIATEL LOGO]
<PAGE>
                                    PART II
                     INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION
 
    The following table sets forth the various expenses, all of which will be
paid by the Registrant in connection with the sale and distribution of the
securities being registered. All of the amounts shown are estimates except the
SEC registration fee.
 
<TABLE>
<S>                                                                               <C>
SEC Registration Fee............................................................  $  68,556
Legal Fees and Expenses.........................................................  $ 400,000
Accounting Fees and Expenses....................................................  $ 300,000
Printing expenses...............................................................  $ 650,000
Miscellaneous expenses..........................................................  $ 381,444
                                                                                  ---------
  Total.........................................................................  $1,800,000
                                                                                  ---------
                                                                                  ---------
</TABLE>
 
ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS
 
    Section 145 of the General Corporations Law of the State of Delaware (the
"DGCL") provides that a Delaware corporation may indemnify any person who was or
is a party or is threatened to be made a party to any threatened, pending or
completed action, suit or proceeding, whether civil, criminal, administrative or
investigative (a "proceeding") (other than an action by or in the right of the
corporation) by reason of the fact that he is or was a director, officer,
employee or agent of the corporation, or is or was serving at the request of the
corporation as a director, officer, employee or agent of another corporation,
partnership, joint venture, trust or other enterprise, against expenses
(including attorneys' fees), judgments, fines and amounts paid in settlement
actually and reasonably incurred by him in connection with such action, suit or
proceeding if he acted in good faith and in a manner he reasonably believed to
be in or not opposed to the best interests of the corporation, and, with respect
to any criminal action or proceeding, had no reasonable cause to believe his
conduct was unlawful. A Delaware corporation may indemnify any person under such
Section in connection with a proceeding by or in the right of the corporation to
procure judgment in its favor, as provided in the preceding sentence, against
expenses (including attorneys' fees) actually and reasonably incurred by him in
connection with the defense or settlement of such action, except that no
indemnification shall be made with respect thereto unless, and then only to the
extent that, a court of competent jurisdiction shall determine upon application
that such person is fairly and reasonably entitled to indemnity for such
expenses as the court shall deem proper. A Delaware corporation must indemnify
present or former directors and officers who are successful on the merits or
otherwise in defense of any action, suit or proceeding or in defense of any
claim, issue or matter in any proceeding, by reason of the fact that he is or
was a director, officer, employee or agent of the corporation or is or was
serving at the request of the corporation, against expenses (including
attorneys' fees) actually and reasonably incurred by him in connection
therewith. A Delaware corporation may pay for the expenses (including attorneys'
fees) incurred by an officer or director in defending a proceeding in advance of
the final disposition upon receipt of an undertaking by or on behalf of such
officer or director to repay such amount if it shall ultimately be determined
that he is not entitled to be indemnified by the corporation. Article Tenth of
the Registrant's Amended and Restated Certificate of Incorporation and Article X
of the Registrant's Amended and Restated Bylaws provide for indemnification of
directors and officers to the fullest extent permitted by Section 145 of the
DGCL.
 
    Section 102(b)(7) of the DGCL permits a corporation to provide in its
certificate of incorporation that a director shall not be personally liable to
the corporation or its stockholders for monetary damages for a breach of
fiduciary duty as a director, except for liability (i) for any breach of the
director's duty of loyalty to the corporation or its stockholders, (ii) for any
acts or omissions not in good faith or which involve intentional misconduct or a
knowing violation of law, (iii) with respect to certain unlawful dividend
 
                                      II-1
<PAGE>
payments or stock redemptions or repurchases or (iv) for any transaction from
which the director derived an improper personal benefit. Article Ninth of the
Registrant's Amended and Restated Certificate of Incorporation eliminates the
liability of directors to the fullest extent permitted by Section 102(b)(7) of
the DGCL.
 
    Section 145 of the DGCL permits a corporation to purchase and maintain
insurance on behalf of any person who is or was a director, officer, employee or
agent of the corporation, or is or was serving at the request of the corporation
as a director, officer, employee or agent of another corporation, partnership,
joint venture, trust or other employee against any liability asserted against
such person and incurred by such person in such capacity, or arising out of
their status as such, whether or not the corporation would have the power to
indemnify directors and officers against such liability. The Registrant has
obtained officers' and directors' liability insurance of $15 million for members
of its Board of Directors and executive officers. In addition, the Registrant
has entered into agreements to indemnify its directors and officers from and
against any Expenses (as defined in the indemnity agreement) incurred by such
person in connection with investigating, defending, serving as a witness in,
participating in (including on appeal) or preparing for any of the foregoing in
any threatened, pending or contemplated action, suit or proceeding (including an
action by or in the right of the Registrant), or any inquiry, hearing or
investigation, to the fullest extent permitted by law, as such law may be
amended or interpreted (but only to the extent that such amendment or
interpretation provides for broader indemnification rights). The indemnity
agreement contains certain provisions to ensure that the indemnitee receives the
benefits contemplated by the agreement in the event of a "change in control" (as
defined in the indemnity agreement) such as the establishment and funding of a
trust in an amount sufficient to satisfy any and all expenses reasonably
anticipated to be incurred by the indemnitee in connection with investigating,
preparing for, participating in and/or defending a proceeding.
 
    At present, there is no pending litigation or other proceeding involving a
director or officer of the Registrant as to which indemnification is being
sought, nor is the Registrant aware of any threatened litigation that may result
in claims for indemnification by any officer or director.
 
ITEM 16. EXHIBITS
 
<TABLE>
<CAPTION>
  EXHIBIT
  NUMBER                                             DESCRIPTION OF DOCUMENT
- -----------  --------------------------------------------------------------------------------------------------------
<C>          <S>
 
     1.1***  Form of Underwriting Agreement between Viatel, Inc. and the representatives of the Underwriters.
 
     4.1***  Indenture, dated as of April 8, 1998, between Viatel, Inc. and The Bank of New York, as Trustee,
             relating to Viatel, Inc.'s 12.50% Senior Discount Notes Due 2008 (including form of 12.50% Senior
             Discount Note) (incorporated herein by reference to Exhibit 4.1 to Viatel, Inc.'s Registration Statement
             on Form S-4, filed on July 10, 1998, Registration No. 333-58921 ("Viatel's 1998 Form S-4")).
 
      4.2*   Indenture, dated as of April 8, 1998, between Viatel, Inc. and The Bank of New York, as Trustee,
             relating to Viatel, Inc.'s 11.25% Senior Notes Due 2008 (including form of 11.25% Senior Note)
             (incorporated herein by reference to Exhibit 4.2 to Viatel's 1998 Form S-4).
 
      4.3*   Indenture, dated as of April 8, 1998, among Viatel, Inc., The Bank of New York, as Trustee, and Deutsche
             Bank, Aktiengesellschaft, as German Paying Agent and Co-Registrar, relating to Viatel, Inc.'s 12.40%
             Senior Discount Notes Due 2008 (including form of 12.40% Senior Discount Note) (incorporated herein by
             reference to Exhibit 4.3 to Viatel's 1998 Form S-4).
</TABLE>
 
                                      II-2
<PAGE>
<TABLE>
<CAPTION>
  EXHIBIT
  NUMBER                                             DESCRIPTION OF DOCUMENT
- -----------  --------------------------------------------------------------------------------------------------------
<C>          <S>
      4.4*   Indenture, dated as of April 8, 1998, among Viatel, Inc., The Bank of New York, as Trustee, and Deutsche
             Bank, Aktiengesellschaft, as German Paying Agent and Co-Registrar, relating to Viatel, Inc.'s 11.15%
             Senior Notes Due 2008 (including form of 11.15% Senior Note) (incorporated herein by reference to
             Exhibit 4.4 to Viatel's 1998 Form S-4).
 
      4.5*   Indenture, dated as of April 8, 1998, among Viatel, Inc., The Bank of New York, as Trustee, and Deutsche
             Bank, Aktiengesellschaft, as German Paying Agent and Co-Registrar, relating to Viatel, Inc.'s 10%
             Subordinated Convertible Debentures Due 2011 (including form of 10% Subordinated Convertible Debenture)
             (incorporated herein by reference to Exhibit 4.5 to Viatel's 1998 Form S-4).
 
      4.6*   Conversion Shares Registration Rights Agreement, dated April 3, 1998, among Viatel, Inc., Morgan Stanley
             & Co. Incorporated, Morgan Stanley Bank AG, Salomon Brothers Inc, ING Baring (U.S.) Securities, Inc. and
             NationsBanc Montgomery Securities LLC (incorporated herein by reference to Exhibit 4.7 to Viatel's 1998
             Form S-4).
 
      4.7*   Amended and Restated Certificate of Incorporation of Viatel, Inc. (incorporated herein by reference to
             Exhibit 3.1(i)(a) to Viatel, Inc.'s Registration Statement on Form S-1, Registration No. 333-09699,
             filed on August 7, 1996; Certificate of Designations, Preferences and Rights of 10% Series A Redeemable
             Convertible Preferred Stock, $.01 par value (incorporated herein by reference to Exhibit 3(i)(b) to
             Viatel's 1998 Form S-4); Certificate of Amendment to Viatel, Inc.'s Amended and Restated Certificate of
             Incorporation (incorporated herein by reference to Exhibit 4.9 to Viatel, Inc.'s quarterly report on
             Form 10-Q for the quarter ended September 30, 1998, File No. 000-21261).
 
      4.8*   Second Amended and Restated Bylaws of Viatel, Inc. (incorporated herein by reference to Exhibit 3(ii) of
             Viatel, Inc.'s quarterly report on Form 10-Q for the quarter ended September 30, 1997, File No.
             000-21261).
 
      4.9*   Indenture, dated as of March 19, 1999, between Viatel, Inc. and The Bank of New York, as Trustee,
             relating to Viatel, Inc.'s US dollar denominated 11.50% Senior Notes Due 2009 (including form of 11.50%
             Senior Note) (incorporated by reference to Exhibit 4.9 of Viatel's Registration Statement on Form S-3,
             filed on February 12, 1999, Registration No. 333-72309 ("Viatel's February 1999 Form S-3)).
 
      4.10*  Indenture, dated as of March 19, 1999, between Viatel, Inc. and The Bank of New York, as Trustee,
             relating to Viatel, Inc.'s Euro denominated 11.50% Senior Notes Due 2009 (including form of 11.50%
             Senior Note) (incorporated by reference to Exhibit 4.10 of Viatel's February 1999 Form S-3).
 
      4.11*  Registration Rights Agreement, dated as of March 12, 1999, among Viatel, Inc. and the Initial Purchasers
             (incorporated by reference to Exhibit 4.11 of Viatel's February 1999 Form S-3).
 
      4.12*  Specimen common stock certificate (incorporated by reference to Exhibit 4.4 of Viatel's Registration
             Statement on Form S-1, filed on August 7, 1996, Registration No. 333-09699).
 
     5.1***  Opinion of Kelley Drye & Warren LLP.
 
    23.1***  Consent of Kelley Drye & Warren LLP (included in their opinion filed as Exhibit 5.1).
 
     23.2**  Consent of KPMG LLP.
 
   24**      Powers of Attorney (included on signature page).
</TABLE>
 
- ------------------------
 
*   Incorporated herein by reference.
 
**  Filed herewith.
 
*** To be filed by amendment.
 
                                      II-3
<PAGE>
ITEM 17. UNDERTAKINGS
 
    (a) The undersigned Registrant hereby undertakes:
 
(1) To file, during any period in which offers or sales are being made, a
    post-effective amendment to this Registration Statement:
 
        (i) To include any prospectus required by Section 10(a)(3) of the
    Securities Act of 1933;
 
        (ii) To reflect in the prospectus any facts or events arising after the
    effective date of this Registration Statement (or the most recent
    post-effective amendment thereof) which, individually or in the aggregate,
    represent a fundamental change in the information set forth in this
    Registration Statement. Notwithstanding the foregoing, any increase or
    decrease in volume of securities offered (if the total dollar value of
    securities offered would not exceed that which was registered) and any
    deviation from the low or high end of the estimated maximum offering range
    may be reflected in the form of prospectus filed with the Commission
    pursuant to Rule 424(b) if, in the aggregate, the changes in volume and
    price, represent no more than 20 percent change in the maximum aggregate
    offering price set forth in the "Calculation of Registration Fee" table in
    the effective Registration Statement; and
 
        (iii) To include any material information with respect to the plan of
    distribution not previously disclosed in this Registration Statement or any
    material change to such information in this Registration Statement.
 
PROVIDED, HOWEVER, that paragraphs (a)(1)(i) and (a)(1)(ii) above do not apply
if the information required to be included in a post-effective amendment by
those paragraphs is contained in periodic reports filed with or furnished to the
Commission by the Registrant pursuant to Section 13 or Section 15(d) of the
Securities Exchange Act of 1934, that are incorporated by reference in this
Registration Statement.
 
        (2) That, for the purpose of determining any liability under the
    Securities Act of 1933, each such post-effective amendment shall be deemed
    to be a new registration statement relating to the securities offered
    therein, and the offering of such securities at that time shall be deemed to
    be the initial BONA FIDE offering thereof.
 
        (3) To remove from registration by means of a post-effective amendment
    any of the securities being registered which remain unsold at the
    termination of the offering.
 
    (b) The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
registrant's annual report pursuant to Section 13(a) or 15(d) of the Securities
Exchange Act of 1934 (and, where applicable, each filing of an employee benefit
plan's annual report pursuant to Section 15(d) of the Securities Exchange Act of
1934) that is incorporated by reference in this Registration Statement shall be
deemed to be a new registration statement relating to the securities offered
therein, and the offering of such securities at that time shall be deemed to be
the initial BONA FIDE offering thereof.
 
    (c) Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers and controlling persons of
the Registrant pursuant to the foregoing provisions, or otherwise, the
Registrant has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the
Securities Act of 1933 and is, therefore, unenforceable. In the event that a
claim for indemnification against such liabilities (other than the payment by
the Registrant of expenses incurred or paid by a director, officer or
controlling person of the Registrant in the successful defense of any action,
suit or proceeding) is asserted by such director, officer or controlling person
in connection with the securities being registered, the Registrant will, unless
in the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the
Securities Act of 1933 and will be governed by the final adjudication of such
issue.
 
                                      II-4
<PAGE>
                                   SIGNATURES
 
    Pursuant to the requirements of the Securities Act, the Registrant, Viatel,
Inc. certifies that it has reasonable grounds to believe that it meets all of
the requirements for filing on Form S-3 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of New York, State of New York on this 20th day of May,
1999.
 
                                VIATEL, INC.
 
                                BY:  /S/ MICHAEL J. MAHONEY
                                       ----------------------------------------
                                        Michael J. Mahoney
                                     CHAIRMAN OF THE BOARD, PRESIDENT AND CHIEF
                                             EXECUTIVE OFFICER
 
                               POWER OF ATTORNEY
 
    KNOW ALL PERSONS BY THESE PRESENTS, that the persons whose signatures appear
below, constitute and appoint Michael J. Mahoney, Allan L. Shaw and Sheldon M.
Goldman, and each of them, as their true and lawful attorneys-in-fact and
agents, with full power of substitution and resubstitution, for them and in
their names, places, steads, in any and all capacities, to sign this
Registration Statement to be filed with the Securities and Exchange Commission
and any and all amendments (including post-effective amendments) to this
Registration Statement, and any subsequent registration statement filed pursuant
to Rule 462 (b) under the Securities Act of 1933, as amended, and to file the
same, with all exhibits thereto, and other documents in connection therewith,
with the Securities and Exchange Commission, granting unto said
attorneys-in-fact and agents, and each of them, full power and authority to do
and perform each and every act and thing requisite and necessary to be done in
connection therewith, as fully to all intents and purposes as they might or
could do in person, thereby ratifying and confirming all that said
attorneys-in-fact and agents, or any of them, or their or his or her substitute
or substitutes, may lawfully do or cause to be done by virtue hereof.
 
    Pursuant to the requirements of the Securities Act of 1933, as amended, this
Registration Statement has been signed below by the following persons in the
capacities indicated on May 20, 1999.
 
          SIGNATURE                        TITLE
- ------------------------------  ---------------------------
                                Chairman of the Board,
    /s/ MICHAEL J. MAHONEY        President and Chief
- ------------------------------    Executive Officer
      Michael J. Mahoney          (Principal Executive
                                  Officer)
 
                                Senior Vice President,
      /s/ ALLAN L. SHAW           Finance, Chief Financial
- ------------------------------    Officer and Director
        Allan L. Shaw             (Principal Financial and
                                  Accounting Officer)
 
     /s/ PAUL G. PIZZANI        Director
- ------------------------------
       Paul G. Pizzani
 
     /s/ FRANCIS J. MOUNT       Director
- ------------------------------
       Francis J. Mount
 
      /s/ JOHN G. GRAHAM        Director
- ------------------------------
        John G. Graham
 
                                      II-5
<PAGE>
                               INDEX TO EXHIBITS
 
<TABLE>
<CAPTION>
 EXHIBIT
  NUMBER                                           DESCRIPTION OF DOCUMENT
- ----------  -----------------------------------------------------------------------------------------------------
<C>         <S>
    1.1***  Form of Underwriting Agreement between Viatel, Inc. and the representatives of the Underwriters.
    4.1*    Indenture, dated as of April 8, 1998, between Viatel, Inc. and The Bank of New York, as Trustee,
            relating to Viatel, Inc.'s 12.50% Senior Discount Notes Due 2008 (including form of 12.50% Senior
            Discount Note) (incorporated herein by reference to Exhibit 4.1 to Viatel, Inc.'s Registration
            Statement on Form S-4, filed on July 10, 1998, Registration No. 333-58921 ("Viatel's 1998 Form
            S-4")).
 
    4.2*    Indenture, dated as of April 8, 1998, between Viatel, Inc. and The Bank of New York, as Trustee,
            relating to Viatel, Inc.'s 11.25% Senior Notes Due 2008 (including form of 11.25% Senior Note)
            (incorporated herein by reference to Exhibit 4.2 to Viatel's 1998 Form S-4).
 
    4.3*    Indenture, dated as of April 8, 1998, among Viatel, Inc., The Bank of New York, as Trustee, and
            Deutsche Bank, Aktiengesellschaft, as German Paying Agent and Co-Registrar, relating to Viatel,
            Inc.'s 12.40% Senior Discount Notes Due 2008 (including form of 12.40% Senior Discount Note)
            (incorporated herein by reference to Exhibit 4.3 to Viatel's 1998 Form S-4).
 
    4.4*    Indenture, dated as of April 8, 1998, among Viatel, Inc., The Bank of New York, as Trustee, and
            Deutsche Bank, Aktiengesellschaft, as German Paying Agent and Co-Registrar, relating to Viatel,
            Inc.'s 11.15% Senior Notes Due 2008 (including form of 11.15% Senior Note) (incorporated herein by
            reference to Exhibit 4.4 to Viatel's 1998 Form S-4).
 
    4.5*    Indenture, dated as of April 8, 1998, among Viatel, The Bank of New York, as Trustee, and Deutsche
            Bank, Aktiengesellschaft, as German Paying Agent and Co-Registrar, relating to Viatel, Inc.'s 10%
            Subordinated Convertible Debentures Due 2011 (including form of 10% Subordinated Convertible
            Debenture) (incorporated herein by reference to Exhibit 4.5 to Viatel's 1998 Form S-4).
 
    4.6*    Conversion Shares Registration Rights Agreement, dated April 3, 1998, among Viatel, Inc., Morgan
            Stanley & Co. Incorporated, Morgan Stanley Bank AG, Salomon Brothers Inc, ING Baring (U.S.)
            Securities, Inc. and NationsBanc Montgomery Securities LLC (incorporated herein by reference to
            Exhibit 4.7 to Viatel's 1998 Form S-4).
 
    4.7*    Amended and Restated Certificate of Incorporation of Viatel, Inc. (incorporated herein by reference
            to Exhibit 3.1(i)(a) to Viatel, Inc.'s Registration Statement on Form S-1, Registration No.
            333-09699, filed on August 7, 1996; Certificate of Designations, Preferences and Rights of 10% Series
            A Redeemable Convertible Preferred Stock, $.01 par value (incorporated herein by reference to Exhibit
            3(i)(b) to Viatel's 1998 Form S-4); Certificate of Amendment to Viatel, Inc.'s Amended and Restated
            Certificate of Incorporation (incorporated herein by reference to Exhibit 4.9 to Viatel, Inc.'s
            quarterly report on Form 10-Q for the quarter ended September 30, 1998, File No. 000-21261).
 
    4.8*    Second Amended and Restated Bylaws of Viatel, Inc. (incorporated herein by reference to Exhibit 3(ii)
            of Viatel, Inc.'s Form 10-Q for the quarter ended September 30, 1997, File No. 000-21261).
 
    4.9*    Indenture, dated as of March 19, 1999, between Viatel, Inc. and The Bank of New York, as Trustee,
            relating to Viatel, Inc.'s US dollar denominated 11.50% Senior Notes Due 2009 (including form of
            11.50% Senior Note). (incorporated by reference to Exhibit 4.9 of Viatel's Registration Statement on
            Form S-3, filed on February 12, 1999, Registration No. 333-72309 ("Viatel's February 1999 Form S-3)).
</TABLE>
<PAGE>
<TABLE>
<CAPTION>
 EXHIBIT
  NUMBER                                           DESCRIPTION OF DOCUMENT
- ----------  -----------------------------------------------------------------------------------------------------
<C>         <S>
    4.10*   Indenture, dated as of March 19, 1999, between Viatel, Inc. and The Bank of New York, as Trustee,
            relating to Viatel, Inc.'s Euro denominated 11.50% Senior Notes Due 2009 (including form of 11.50%
            Senior Note) (incorporated by reference to Exhibit 4.10 of Viatel's February 1999 Form S-3).
 
    4.11*   Registration Rights Agreement, dated as of March 12, 1999, among Viatel, Inc. and the Initial
            Purchasers (incorporated by reference to Exhibit 4.11 of Viatel's February 1999 Form S-3).
 
    4.12*   Specimen common stock certificate (incorporated by reference to Exhibit 4.4 of Viatel's Registration
            Statement on Form S-1, filed on August 7, 1996, Registration No. 333-09699).
 
    5.1***  Opinion of Kelley Drye & Warren LLP as to the validity of the securities being registered.
 
   23.1***  Consent of Kelley Drye & Warren LLP (included in their opinion filed as Exhibit 5.1).
 
   23.2**   Consent of KPMG LLP.
 
 24**       Powers of Attorney (included on original S-3 signature page).
</TABLE>
 
- ------------------------
 
*   Incorporated herein by reference
 
**  Filed herewith.
 
*** To be filed by Amendment.

<PAGE>
                                                                    EXHIBIT 23.2
 
                         INDEPENDENT AUDITORS' CONSENT
 
The Board of Directors and Stockholders
Viatel, Inc.:
 
We consent to the use of our reports included herein and to the reference to our
firm under the heading "Selected Consolidated Financial Data" and "Experts" in
the registration statement.
 
                                            /s/ KPMG LLP
 
New York, New York
May 19, 1999


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