<PAGE>


                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   FORM 10-K/A
                               AMENDMENT NO. 1 TO
                    ANNUAL REPORT PURSUANT TO 13 OR 15(d) OF
                       THE SECURITIES EXCHANGE ACT OF 1934

                   For the fiscal year ended December 31, 1999
                        Commission file number: 000-24653

                          NORTHEAST OPTIC NETWORK, INC.
             (Exact name of registrant as specified in its charter)

            DELAWARE                                 04-3056279
  (State or other jurisdiction                    (I.R.S. Employer
of incorporation or organization)               Identification Number)

                              2200 WEST PARK DRIVE
                                    SUITE 200
                        WESTBOROUGH, MASSACHUSETTS 01581
                                 (508) 616-7800
    (Address, including zip code, and telephone number, including area code,
                  of registrant's principal executive offices)

          Securities registered pursuant to Section 12(b) of the Act:
                                      None

          Securities registered pursuant to Section 12(g) of the Act:
                          Common Stock, Par Value $0.01

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Sections 13 or 15(d) of the Securities Exchange Act of 1934
during the preceding 12 months (or for such shorter period that the registrant
was required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days. Yes /X/ No / /

Indicate by a check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to the
Form 10-K. /X/

The aggregate market value of the Common Stock held by non-affiliates of the
registrant, based on the last sale price of the Common Stock reported on the
Nasdaq National Market on March 31, 2000 was $474,822,429.

The number of shares of Common Stock outstanding as of March 31, 2000 was
16,624,380.

                       DOCUMENTS INCORPORATED BY REFERENCE

None.



                                      -1-
<PAGE>


         NorthEast Optic Network, Inc. (the "Company") hereby amends its Annual
Report on Form 10-K for the year ended December 31, 1999 to include the
information required under Part III.

PART III

ITEM 10. DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT

The following table sets forth our executive officers and directors and their
ages as of April 1, 2000:


<TABLE>
<CAPTION>

Name                            Age     Position
------------------------------------------------------------------------------------
<S>                             <C>     <C>
Vincent C. Bisceglia.......     45      Chairman of the Board of Directors and Chief
                                                Executive Officer
Victor Colantonio..........     52      Vice Chairman of the Board of Directors and
                                                President
William F. Fennell.........     55      Chief Financial Officer, Treasurer and Vice
                                                President, Finance
Michael C. Musen...........     51      Vice President, Operations
Arthur W. Adelberg.........     48      Director
Katherine Dietze Courage...     41      Director (1)(2)
John H. Forsgren...........     53      Director (1)
F. Michael McClain.........     50      Director (1)(2)
Gary D. Simon..............     51      Director (2)
</TABLE>


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

(1) Member of Compensation Committee

(2) Member of Audit Committee

VINCENT C. BISCEGLIA, our chairman and chief executive officer, has served in
his current position since November 1998. From December 1997 to November 1998,
Mr. Bisceglia served as an independent consultant. From February 1994 to
December 1997, Mr. Bisceglia served as president and chief executive officer and
a director of Technology Service Group, Inc., a manufacturer of advanced
technology pay telephones. Prior to 1994, he served Technology Service Group,
Inc. in various management positions. From 1982 to 1986, Mr. Bisceglia was
executive vice president and chief operating officer of Transaction Management,
Inc., a manufacturer of point-of-sale systems, and from 1978 to 1982, he held
senior marketing positions with National Semiconductor-DTS and Siemens-Nixdorf
Computer Corporation.

VICTOR COLANTONIO, our founder, vice chairman of the board of directors and
president, has been a member of our board of directors since 1989. From 1987 to
1991, Mr. Colantonio was president of International Communications Services
Corp. He served as president of Ireland-based Murray International from 1986 to
1987, where he sold network services. From 1983 to 1986, Mr. Colantonio served
as director of marketing for Tele-Engineering Corp., an advanced WAN/LAN
developer and video switch and ad-insertion manufacturer.

WILLIAM F. FENNELL joined us in August 1996 and became our chief financial
officer and treasurer in May 1997 and our vice president, finance in May 1998.
From October 1986 to January 1996, Mr. Fennell was chief financial officer of
Philips Electronics Group of North America, a manufacturer and distributor of
electronic and electrical products. From 1970 to 1986, Mr. Fennell served in
various positions at GTE Corporation, including director of operations for the
Communications Products Group.




                                      -2-
<PAGE>

MICHAEL A. MUSEN has served as one of our officers since 1992, and became vice
president, operations in 1996.

ARTHUR W. ADELBERG has served as one of our directors since May 1999.
Mr. Adelberg has served as executive vice president and chief financial officer
of CMP Group, Inc. since December 1999. From September 1998 through
November 1999, Mr. Adelberg served as executive vice president of CMP Group,
Inc. and from March 1994 through August 1998 served as vice president law and
power supply of Central Maine Power Company and served in a number of senior
management roles at Central Maine Power Company from 1985 through March 1994.
Mr. Adelberg is a member of the Executive Committee of the New England Power
Pool.

KATHERINE DIETZE COURAGE has served as a member of our board of directors since
August 1998. Ms. Courage has served since 1996 as a managing director in the
Global Media and Telecommunications Group in the Investment Banking Department
of Credit Suisse First Boston.  Prior to joining Credit Suisse First Boston in
September 1996, Ms. Courage worked at Salomon Brothers, Inc. for ten years where
she was a managing director with responsibility for the Global
Telecommunications Group. Ms. Courage also worked at Merrill Lynch & Co. in its
corporate finance department.

JOHN H. FORSGREN has served as a member of our board of directors since May
1998. Mr. Forsgren has served as executive vice president and chief financial
officer of Northeast Utilities and certain of its affiliates since February
1996. From September 1996 to the present, he has served as a director of
Connecticut Yankee Atomic Power Company. From January 1990 to July 1994, he
served as senior vice president-chief financial officer of Euro Disney (a
division of the Walt Disney Company). From December 1994 to January 1996, he was
a managing director of Chase Manhattan Bank.

F. MICHAEL MCCLAIN has served as a member of our board of directors since May
1998. Mr. McClain has served as vice president, corporate development of CMP
Group, Inc. since September 1998. He held the same position at Central Maine
Power Company from February 1998 to August 1998. From 1979 to December 1996, he
was group vice president-petroleum for Dead River Company, a petroleum and real
estate company.

GARY D. SIMON has served as a member of our board of directors since May 1998.
Mr. Simon has served as senior vice president-strategy and development for the
Northeast Utilities System since April 1998. From 1989 to April 1998, he was
senior director, Electric Power of Cambridge Energy Research Associates. From
1984 to 1989, Mr. Simon was director of California affairs and then vice
president of marketing for El Paso Natural Gas Company. From 1981 to 1984, he
served as president of Sigma Group, an economics consulting and project
development company which he founded in 1981.



                                      -3-
<PAGE>


Item 11. EXECUTIVE COMPENSATION

Compensation Earned

The following table sets forth the compensation for the fiscal years ended
December 31, 1997, 1998 and 1999 for (1) our chief executive officer and (2) our
three most highly compensated executive officers (other than our chief executive
officer) whose total annual salary and bonus exceeded $100,000 in 1999,
collectively referred to as the named executive officers.

                           Summary Compensation Table

<TABLE>
<CAPTION>

                                                                                      Long-Term
                                                                                     Compensation
                                                         Annual Compensation            Awards
                                                        ----------------------     ----------------
                                                                                        Shares
                                                                                      Underlying        All Other
Name and Principal Position               Year               Salary         Bonus         Options       Compensation (1)
------------------------------------    ---------        -------------  ---------- -----------------   -----------------
<S>                                       <C>                 <C>         <C>               <C>                  <C>
Vincent C. Bisceglia...........           1999               $211,746   $ 299,628                --             $4,124
    CHAIRMAN OF THE BOARD, CHIEF          1998                 25,845          --           350,000                 --
    EXECUTIVE OFFICER AND DIRECTOR        1997                     --          --                --                 --

Victor Colantonio..............           1999                203,325          --                --              4,994
    VICE CHAIRMAN OF THE BOARD,           1998                174,556     500,000           649,628              4,800
    PRESIDENT AND DIRECTOR                1997                150,000       2,885                --                 --

William F. Fennell.............           1999                127,175          --                --              3,840
    CHIEF FINANCIAL OFFICER,              1998                111,436          --           162,407              3,246
    TREASURER AND ASSISTANT               1997                 91,731          --                --                 --
    SECRETARY

Michael A. Musen...............           1999                115,855          --            60,000              3,557
    VICE PRESIDENT, OPERATIONS            1998                123,313          --            40,601              3,592
                                          1997                112,000       2,154                --                 --
</TABLE>

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

1. These amounts represent amounts paid by us on behalf of the named executive
officer as 401K contributions and group life insurance premiums.



                                      -4-
<PAGE>


OPTION GRANTS


         The table below contains information concerning the grant of options
to purchase shares of our common stock to each of the named executive
officers during the year ended December 31, 1999. The percentage of total
options granted to employees set forth below is based on an aggregate of
710,165 shares subject to options granted to our employees in 1999. All
options were granted at or above fair market value as determined by the board
of directors on the date of grant.


                                  Option Grants in Last Fiscal Year


<TABLE>
<CAPTION>

                                                                                Potential Realizable Value at
                                                                                Assumed Annual Rates of Stock
                                                                                Price Appreciation for Option
                                              Individual Grants                              Term (1)
                             ---------------------------------------------------- -------------------------------
                              Number of    Percent of
                             Securities      Total      Exercise
                             Underlying     Options     Price Per
                               Options     Granted to   Share        Expiration
Name                           Granted     Employees     ($/sh)       Date (2)             5%             10%
----                         ----------    ----------   ---------    ----------        ----------     ----------
<S>                          <C>           <C>          <C>          <C>               <C>            <C>
Vincent C. Biscaglia(3)..    299,628         42.1%        $12.00        01/01/09       $2,261,213     $5,730,358

Victor Colantonio........         --          --           --                 --               --             --

William F. Fennell.......         --          --           --                 --               --             --

Michael A. Musen(4)......     60,000          8.4         29.38         08/18/09        1,108,427      2,808,971
</TABLE>


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

1. The amounts shown in these columns represent hypothetical gains that could be
achieved if the options were exercised at the end of the option term. These
gains are based on assumed rates of stock appreciation of 5% and 10%, compounded
annually from the date the option was granted to its expiration date. The gains
shown are net of the option exercise price, but do not include deductions for
taxes or other expenses associated with an exercise. Actual gains, if any, on a
stock option exercise will depend on the future performance of our common stock,
the option holder's continued employment, and the date on which the option is
exercised.

2. The expiration date of each option is the tenth anniversary of the date on
which the option was granted.


3. This option becomes exercisable as to 137,221 shares on November 11, 2001
and as to the remaining shares on November 11, 2002.

4. This option is exercisable in three equal annual installments beginning
on August 18, 2000.


AGGREGATED OPTION EXERCISES IN LAST FISCAL YEAR AND FISCAL YEAR-END OPTION
VALUES

The following table sets forth certain information concerning each exercise of a
stock option during the fiscal-year ended December 31, 1999 by each of the named
executive officers and the number and "value" of unexercised options held by
each of the named executive officers on December 31, 1999. The value of an
unexercised option for purposes of this table is the difference between the fair
market value of our common stock on December 31, 1999 ($62.563 per share, as
quoted on the Nasdaq National Market) and the option's exercise price,
multiplied by the number of shares underlying the option.



                                      -5-
<PAGE>


                   Aggregated Option Exercised in Fiscal 1999
                        and Fiscal Year-End Option Values

<TABLE>
<CAPTION>

                                                           Number of Securities
                                                           Underlying Unexercised       Value of Unexercised In-the-Money
                                                         Options at Fiscal Year-End         Options at Fiscal Year-End

                             Shares Acquired
Name                           on Exercise     Value Realized   Exercisable   Unexercisable      Exercisable       Unexercisable
----                         ---------------   --------------   -----------   -------------      -----------       -------------
<S>                             <C>            <C>               <C>             <C>             <C>               <C>
Vincent C. Bisceglia.......     51,827         $3,149,361        110,580         487,221         $6,245,006        $25,744,405

Victor Colantonio..........         85              4,420        324,729         324,814         16,419,272         16,423,570

William F. Fennell.........     28,500          1,553,330         52,704          81,203          2,664,872          4,105,867

Michael A. Musen...........         --                 --         40,602          60,000          2,052,958          1,991,280
</TABLE>


EMPLOYMENT, TERMINATION AND CHANGE-IN-CONTROL ARRANGEMENTS

     Mr. Bisceglia serves as our chief executive officer pursuant to the terms
of an employment agreement dated November 12, 1998 and made effective November
5, 1998. The agreement has an initial term expiring on December 31, 2001 and is
automatically extended for one year periods unless either party gives notice no
later than the immediately preceding July 1 of its desire to terminate the
agreement. The agreement provides for an annual base salary of not less than
$210,000 and for the grant of two options in November 1998 and a third option in
January 1999. The first two options cover 350,000 shares in the aggregate which
become exercisable at $6.0875 per share, as to 162,407 shares on each of
November 11, 1999 and 2000 and as to 25,186 shares on November 11, 2001; the
third option covers 299,628 shares and becomes exercisable at $12.00 per share
as to 137,221 shares on November 11, 2001 and as to 162,407 shares on November
11, 2002. In addition to being eligible to participate in our executive and
employee plans, Mr. Bisceglia has an opportunity to earn an annual bonus of up
to 35% of his base salary upon achieving certain performance goals. If Mr.
Bisceglia's employment is terminated for any reason other than death, total
disability or cause or if we elects not to renew the agreement after the
occurrence of a change of control, Mr. Bisceglia will be entitled to receive a
lump sum payment in an amount equal to 2.99 times his then-current base salary.
If in the absence of a change of control the agreement is not renewed or Mr.
Bisceglia's employment is terminated for any reason other than death, total
disability or cause or by him within six months of a constructive discharge, Mr.
Bisceglia will be entitled to receive a lump sum payment in an amount equal to
his base salary in effect immediately preceding his termination or constructive
discharge, as the case may be.


     Mr. Colantonio serves as our president pursuant to the terms of an
employment agreement dated October 15, 1997, as amended. The agreement has an
initial term of three years and is automatically extended for one-year terms
thereafter unless either party gives written notice no later than the
immediately preceding April 1 of its desire to terminate the agreement. The
agreement provides for an annual base salary of not less than $150,000. If
Mr. Colantonio's employment is terminated without cause after the occurrence
of a change of control, Mr. Colantonio will be entitled to receive a lump sum
payment in an amount equal to 2.99 times his then-current base salary. Upon
consummation of our initial public offering of Common Stock, Mr. Colantonio's
annual base salary was increased to $200,000, as provided for in the
agreement. Mr. Colantonio and the Company have decided not to renew Mr.
Colantonio's current agreement, but intend to negotiate a new agreement
commensurate with Mr. Colantonio's position as Vice Chairman and President
and which takes into account the fact that the Company is now publicly
traded, among other matters.


     Mr. Fennell serves as our chief financial officer pursuant to the terms of
an employment agreement dated July 1, 1998. The agreement has an initial term
expiring on July 30, 2001. The agreement provides for an annual base salary of
not less than $125,000 per year, as well as an option to purchase 162,407 shares
of our common stock at $12.00 per share evidenced by a stock option agreement
which provides that the option vests as to 40,602 shares on each of May 20,
1998, August 5, 1999 and August 5, 2000 and as to 40,601 shares on August 5,
2001. Pursuant to the agreement,



                                      -6-
<PAGE>


Mr. Fennell is also entitled to participate in our executive incentive plan and
has an opportunity to earn an annual bonus, targeted at 25% of his base salary.

     Mr. Musen serves as our vice president, operations pursuant to the terms of
an employment agreement dated September 29, 1994. The agreement has a term of
three years and renews automatically on an annual basis unless terminated by
either party on at least 180 days' notice. The agreement provides for an annual
base salary of not less than $112,000. In addition, in June 1998 the board of
directors granted to Mr. Musen an option to purchase 40,601 shares of our common
stock, exercisable in full upon August 5, 1998 with an exercise price per share
of $12.00.

     Pursuant to the provisions of our Amended and Restated 1998 Stock Incentive
Plan, under which the foregoing options were granted, all options become
exercisable in full upon a change in control.

COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION

     During 1999, Messrs. Bisceglia and Colantonio served on the board of
directors and served as executive officers. No interlocking relationship exists
between any member of our compensation committee and any member of any other
corporation's board of directors or compensation committee.

     The current members of our compensation committee are Ms. Courage and
Messrs. Forsgren and McClain. None of our executive officers have served as a
director or member of the compensation committee (or other committee serving an
equivalent function) of any other entity, whose executive officers served as a
director of or member of our compensation committee.

COMPLIANCE WITH SECTION 16(a) OF THE EXCHANGE ACT


     Section 16(a) of the Exchange Act and regulations of the Securities and
Exchange Commission (the "Commission") thereunder require our executive officers
and directors, and persons who own more than ten percent of a registered class
of the our equity securities, to file reports of initial ownership and changes
in ownership with the Commission and the National Association of Securities
Dealers, Inc. Such officers, directors and ten-percent stockholders are also
required by the rules of the Commission to furnish us with copies of all Section
16(a) forms they file. Based solely on our review of the copies of such forms
received by it, or written representations from certain reporting persons that
no other reports were required for such persons, we believe that, during or with
respect to the period from January 1, 1999 to December 31, 1999, all of our
executive officers, directors and ten-percent stockholders complied with their
Section 16(a) filing obligations.


REPORT OF THE COMPENSATION COMMITTEE ON EXECUTIVE COMPENSATION

     The Compensation Committee seeks to achieve two primary goals in connection
with executive compensation programs and decisions regarding individual
compensation. First, the Compensation Committee structures executive
compensation programs in a manner that it believes will enable the company to
attract and retain key executives. In order to ensure continuity of certain key
members of management, in 1998 the Board of Directors approved multi-year
employment contracts for our executive officers. Second, executive compensation
programs are intended to provide executives with an equity interest in us so as
to link a portion of their compensation with the performance of our common
stock.

     The compensation programs for executives established by the Compensation
Committee consist of a base salary plus an annual cash bonus and/or a
stock-based equity incentive award.

     In establishing base salaries for executive officers, the Compensation
Committee monitored salaries at other companies, particularly those that are in
the same industry as we are or related industries and/or located in the same
general geographic area as we are, considered historic salary levels of the
individual and the nature of the individual's experience and responsibilities
and compared the individual's base salary with those of other executives. To the
extent determined to be appropriate, the Compensation Committee also considered
our financial performance and the individual's performance.



                                      -7-
<PAGE>


     In establishing bonuses for executive officers, including the Chief
Executive Officer, the Compensation Committee considered a combination of
individual and corporate performance goals to be achieved during the coming
year.

     It is not currently the policy of the Compensation Committee to grant stock
options to executives annually, and the timing of grants to executives, if any,
will depend upon a number of factors, including new hires of executives, the
executives' current stock and option holdings and such other factors as the
Compensation Committee deems relevant. When granting stock options, it has
generally been the policy of the Compensation Committee to fix the exercise
price at 100% of the fair market value of our common stock on the date of grant.

     The compensation of the Chief Executive Officer is currently governed by
his employment agreement established in 1998, which is described under the
heading "Employment, Termination and Change-in-Control Arrangements," above.

COMPENSATION OF DIRECTORS

     The board of directors has adopted a Board Compensation Plan which provides
for the payment of certain fees to non-employee directors. The Board
Compensation Plan specifies that each non-employee director will be paid $20,000
per year of service as a director, payable quarterly in arrears; $500 per board
meeting attended; $250 per committee meeting attended; $300 per telephonic board
meeting attended; and $150 per telephonic committee meeting attended. All
directors are reimbursed for their expenses of attending board and committee
meetings.

     Also pursuant to the Board Compensation Plan, each non-employee director
was granted an initial option to purchase 16,241 shares of our common stock
which is exercisable at $12.00 per share. New non-employee directors will be
granted an option to purchase 16,241 shares of our common stock exercisable at
the then current market price per share. In addition, at the first meeting of
directors following each annual meeting of stockholders, each non-employee
director will be granted an additional option to purchase one-tenth of one
percent (0.1%) of the number of shares of our common stock outstanding on a
fully diluted basis at the then current market price. Options granted under the
Board Compensation Plan vest in four equal installments on the date of grant and
on the first three anniversaries of the date of grant.

ITEM 12.  SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

     The following table sets forth certain information regarding beneficial
ownership of our common stock as of March 31, 2000 by (1) each person who owns
beneficially more than 5% of the outstanding shares of our common stock, which
includes the selling stockholder, (2) each of our directors, (3) our chief
executive officer and the four other most highly compensated executive officers
and (4) all of our directors and executive officers as a group.

     The number of shares of common stock deemed outstanding includes:

-   16,624,380 shares of our common stock outstanding as of March 31, 2000; and

-   shares issuable pursuant to options held by each person included in this
    table which may be exercised within 60 days after March 31, 2000, as set
    forth below.

     Beneficial ownership is determined in accordance with the rules of the
Securities and Exchange Commission, and includes voting and investment power
with respect to shares. Unless otherwise indicated below, to our knowledge, all
persons named in the table have sole voting and investment power with respect to
their shares of common stock, except to the extent authority is shared by
spouses under applicable law. The inclusion of any shares in this table does not
constitute an admission of beneficial ownership for the person named below.



                                      -8-
<PAGE>



<TABLE>
<CAPTION>

                                Shares of Common Stock
                                  Beneficially Owned
Name of Beneficial Owner          Number      Percentage
------------------------       ---------      ----------
<S>                            <C>               <C>
CMP Group, Inc. (1)..........  6,180,801         37.2%
  41 Anthony Avenue
  Augusta, Maine 04330

Northeast Utilities (2)......  4,774,038         28.7
  107 Selden Street
  Berlin, Connecticut 06037

Vincent C. Bisceglia (3).....     74,607            *
Victor Colantonio (4)........    215,029          1.3
William F. Fennell (5).......     21,604            *
Michael C. Musen (6).........     31,501            *
Katherine Dietze Courage
  (7)........................     17,462            *
Arthur W. Adelberg (8).......      8,542            *
F. Michael McClain (9).......     17,462            *
Gary D. Simon (10)...........      5,462            *
John H. Forsgren (11)........      5,462            *
All directors and executive
  officers as a group

  (11 persons) (12)..........    401,530          2.4
</TABLE>


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

*  Represents less than 1% of the outstanding shares of common stock.

(1) All 6,180,801 shares of common stock are held by New England Business Trust.
    New England Business Trust is owned by New England Investment Corp., a
    wholly-owned subsidiary of Mainecom Services which is a wholly-owned
    subsidiary of CMP Group, Inc. The trustees of New England Business Trust are
    New England Investment Corp. and Joseph D. Fay. All actions of New England
    Business Trust require the signature of both trustees. Joseph D. Fay is
    General Counsel, Secretary and Clerk of Mainecom Services and a director of
    New England Investment Corp. Mr. McClain, one of our directors, is Vice
    President, corporate development of CMP Group, Inc. Mr. Adelberg, one of our
    directors, is Executive Vice President and Chief Financial Officer of CMP
    Group, Inc. each of Mr. Adelberg and Mr. McClain disclaim beneficial
    ownership of the shares held by CMP Group, Inc., except to the extent of his
    pecuniary interest, if any.

(2) All shares beneficially owned by Northeast Utilities are held by Mode 1
    Communications, Inc., a wholly-owned subsidiary of Northeast Utilities
    Enterprises, Inc., which is in turn, a wholly-owned subsidiary of Northeast
    Utilities. Mr. Forsgren, one of our directors, is the Executive Vice
    President and Chief Financial Officer of Northeast Utilities and certain of
    its affiliates. Mr. Simon, one of our directors, is the Senior Vice
    President, strategy and development for Northeast Utilities Service Company,
    a subsidiary of Northeast Utilities. each of Messrs. Forsgren and Simon
    disclaims beneficial ownership of the shares held by Mode 1 except to the
    extent of his pecuniary interest, if any.

(3) Includes 58,180 shares issuable pursuant to options.

(4) Includes 213,729 shares issuable pursuant to options and 300 shares held of
    record by Mr. Colantonio's minor child, as to which shares Mr. Colantonio
    disclaims beneficial ownership except as to the extent of his pecuniary
    interest, if any.

(5) Represents 21,204 shares issuable pursuant to options and 400 shares held of
    record by Mr. Fennell's minor children, as to which shares Mr. Fennell
    disclaims beneficial ownership except to the extent of his pecuniary
    interest, if any.

(6) Includes 300 shares held of record by Mr. Musen's minor child as to which
    shares Mr. Musen disclaims beneficial ownership except to the extent of his
    pecuniary interest, if any.



                                      -9-
<PAGE>


(7) Represents 17,462 shares issuable pursuant to options.

(8) Includes 8,042 shares issuable pursuant to options.

(9) Represents 17,462 shares issuable pursuant to options.

(10) Represents 5,462 shares issuable pursuant to options.

(11) Represents 5,462 shares issuable pursuant to options.

(12) Includes 347,003 shares issuable pursuant to options.

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

NORTHEAST UTILITIES AGREEMENTS

     In 1994 and 1995, we entered into a series of agreements (as subsequently
amended and restated in February 1998) with the three principal operating
subsidiaries of Northeast Utilities concerning the provision of rights-of-way
along electric utility towers and inside urban electric utility ducts. Pursuant
to the agreements with Northeast Utilities, the company acquired indefeasible
rights of use in fiber optic filaments placed along Northeast Utilities' rights
of way prior to February 1998 and acquired ownership of fiber optic filaments
placed along Northeast Utilities' rights of way subsequent to February 1998. We
and Northeast Utilities both agreed to use best efforts to complete installation
of the Northeast Utilities system by September 1999. We agreed to pay the cost
of installing the cable and to utilize Northeast Utilities' engineering staff in
carrying out the installation. Under the agreements with Northeast Utilities, we
agreed to pay to Northeast Utilities mileage-based annual fees and a percentage
of the gross revenues that the company generates on the portion of our system
located on Northeast Utilities' rights-of-way.

     A portion of the Northeast Utilities system, comprised of 12 fibers within
the cable, is owned by, and has been set aside for, Northeast Utilities.
Northeast Utilities may lease these fibers to third parties, provided that prior
to September 2001,Northeast Utilities is not permitted to assign any fibers or
resell capacity on its network to certain specified carriers except for certain
limited purposes. After September 2001,Northeast Utilities will be free to use
its network to compete with us.

     Under the agreements with Northeast Utilities, if any proposed segment of
our system's route requires material modifications or unusual expense to make it
available for our fiber, or if Northeast Utilities withdraws any segment from
the route in order to give priority to electrical services, we have the right to
designate additional or alternative route segments, subject to Northeast
Utilities' approval, which shall not be withheld unless such additional or
alternative segments would materially adversely affect their ability to provide
reliable electric service, cause or create safety problems or would not be
feasible for structural reasons. If Northeast Utilities wants to create new
route segments in order to extend the their system, we have a right of first
refusal on the provision of any such segments. If Northeast Utilities obtains
such segments from third parties, Northeast Utilities has agreed to use its best
efforts to obtain for us the unimpeded use of not less than 12 usable single
mode fibers in such segment on terms no less favorable than those provided to
Northeast Utilities.

     The agreements with Northeast Utilities have an initial term of 30 years
and expire in September 2024. Thereafter they automatically renew for five-year
terms, unless one of the parties has given a one-year advance notice of
termination. In the event that Northeast Utilities gives such a notice and
terminates the agreements, it must either, at its option, pay us an amount equal
to the fair market value of their system less the value of their own network or
allow us to retain the indefeasible rights of use and receive from us an annual
payment equal to 10% of our gross revenue from the Northeast Utilities system,
which payment would be in addition to the other annual payments under the
agreements with Northeast Utilities.



                                      -10-
<PAGE>


     In addition to the foregoing, the agreements with Northeast Utilities may
be terminated by Northeast Utilities if we default in the performance of certain
of our obligations under the agreements, including the failure to establish
Northeast Utilities network by September 1999, the failure to obtain and
maintain all necessary government permits, licenses, franchises and approvals,
and the failure to pay amounts due under the agreements, subject in most cases
to cure periods of between 30 and 90 days.

CENTRAL MAINE POWER COMPANY AGREEMENT

     In January 1997, we and Central Maine Power Company entered into an
agreement in which Central Maine Power Company granted us a right of use in
fiber optic filaments within a cable along a certain route in Central Maine
Power Company's service territory. We and Central Maine Power Company both
agreed to use best efforts to complete installation of the Central Maine Power
Company system by January 1999. We have the right to install additional cable in
Central Maine Power Company's service territory, subject to the approval of
Central Maine Power Company, which must not be unreasonably withheld. We are
obligated to pay the cost of installing the cable.

     In exchange for the rights of use, we agreed to pay to Central Maine Power
Company an annual fee beginning, with regard to any particular route segment, in
the first calendar year following the installation date for such route segment.

     Our rights of use do not apply to six fibers that have been set aside for
Central Maine Power Company's use as their network. Central Maine Power Company
may use these fibers for its own business purposes, but may not lease them to
third parties prior to the seventh anniversary of any given installation date.
After the seven-year period, to the extent that Central Maine Power Company has
excess capacity on its network, Central Maine Power Company is required to
negotiate in good faith with us to provide such excess capacity before making it
available to third parties. If we do not enter into an agreement with Central
Maine Power Company for such excess capacity, Central Maine Power Company will
be able to use such capacity to compete with us.

     The agreement with Central Maine Power Company has an initial term of 30
years and expires in January 2027. Thereafter it is renewable at our option for
an additional ten-year term. In the event that we elect to renew the agreement,
we must pay to Central Maine Power Company an annual payment equal to 10% of our
gross annual revenue from the Central Maine Power Company system, which payment
would be in addition to the other annual payments under the agreement with
Central Maine Power Company.

     In addition to the foregoing, the agreement with Central Maine Power
Company may be terminated by them if we default in certain of our obligations
under the agreement and such default is not cured within a designated cure
period.

     We believe that the Northeast Utility agreements and the Central Maine
Power Company agreement are on terms at least as favorable to us as could have
been obtained from unaffiliated third parties. Northeast Utilities has waived
right-of-way fees otherwise payable by the company through 2004 in return for
our agreement to build our system to certain facilities of Northeast Utilities
and to allow them to use 12 fibers on designated route segments in their service
territory.

REORGANIZATION

     We were incorporated in Massachusetts in July 1989 under the name "FiveCom,
Inc." In May 1996, FiveCom LLC, an operating subsidiary a majority of whose
stock was owned by the company, was organized in Massachusetts. Also in May
1996, FiveCom LLC and Mode 1 Communications, Inc. , a subsidiary of Northeast
Utilities, organized NECOM LLC in Massachusetts, with FiveCom LLC owning
approximately 60%, and Mode 1 Communications owning approximately 40% of the
membership interests in NECOM LLC. In December 1996, FiveCom LLC and MaineCom
Services, a wholly-owned subsidiary of Central Maine Power Company, organized
FiveCom of Maine LLC in Massachusetts, with MaineCom Services owning 66.67%, and
FiveCom LLC owning 33.33%, of the membership interests in FiveCom of Maine LLC.



                                      -11-
<PAGE>


     In order to simplify the corporate structure and in contemplation of our
initial public offering of common stock, our major stockholders decided to
reorganize the company. In April 1998, prior to the reorganization described
below, Central Maine Power Company exercised its warrants to purchase 5,876
shares of membership interests in FiveCom LLC for a total exercise price of
$58.76. In July 1998, the company entered into a Restructuring and Contribution
Agreement with, among others, Central Maine Power Company, MaineCom Services (an
affiliate of Central Maine Power Company) and Mode 1 Communications, Inc. (an
affiliate of Northeast Utilities) relating to the reorganization described
below, pursuant to which each of the minority members in FiveCom LLC (and each
of Mode 1 Communications, Inc. and MaineCom Services) exchanged their membership
interests in FiveCom LLC, NECOM LLC and FiveCom of Maine LLC, respectively, for
shares of the Series B Convertible Preferred Stock of the company; FiveCom LLC
and NECOM LLC were each merged with and into a wholly-owned subsidiary of the
company; FiveCom of Maine LLC was merged into FiveCom of Maine, Inc., a
wholly-owned subsidiary of the company; and the company was reincorporated in
Delaware under the name "NorthEast Optic Network, Inc." and our Certificate of
Incorporation was amended and restated. The foregoing actions constituted a
reorganization of the company. The shares of membership interest in FiveCom LLC
received by Central Maine Power Company upon exercise of its warrant were
exchanged for 144,172 shares of the Series B Convertible Preferred Stock of the
company, and those shares had an estimated value at the time of the
reorganization of approximately $4.3 million. Mr. Colantonio and Mr. Musen
exchanged their membership interests in FiveCom LLC for 17,788 shares and 14,549
shares, respectively, of our Series B Convertible Preferred Stock, and those
shares had an estimated value at the time of the reorganization of approximately
$542,000 and $443,000, respectively. The Company believes that the value of the
membership interests exchanged in the reorganization was equivalent to the value
of the shares issued in respect of each such membership interest.

CMP GROUP, INC., MAINECOM SERVICES, NEW ENGLAND BUSINESS TRUST AND NORTHEAST
UTILITIES AGREEMENT

     In March 2000, we entered into a memorandum of understanding with CMP
Group, Inc., MaineCom Services, New England Business Trust and Northeast
Utilities. Under the memorandum of understanding, we agreed to file a
registration statement to register certain shares of common stock held by New
England Business Trust in response to the exercise of a demand registration
request by New England Business Trust under a 1995 agreement. The registration
statement of which this prospectus forms a part is in response to that request.
New England Business Trust also agreed to reimburse us for some of the expenses
that we incur in connection with this offering, which amount shall not exceed
$575,000. Pursuant to the 1995 agreement, we agreed to indemnify New England
Business Trust against certain liabilities, including liabilities under the
Securities Act.

     Under the memorandum of understanding, Northeast Utilities and New
England Business Trust also agreed to amend the existing stockholders
agreement between them to provide that each of them may sell shares of common
stock pursuant to Rule 144 of the Securities Act without regard to the right
of first offer provision contained in the stockholders agreement between them
and that each of them would agree to vote for two directors nominated to our
board of directors by the other. See "Principal Stockholders Agreement"
below. Northeast Utilities and New England Business Trust also agreed that in
the event Northeast Utilities holds less than 2,060,953 shares, New England
Business Trust would only be obligated to vote for one director nominated by
Northeast Utilities and that the voting obligation would be eliminated if
Northeast Utilities holds less than 772,917 shares. Likewise, in the event
that New England Business Trust holds less than 2,701,629 shares, Northeast
Utilities would only be obligated to vote for one director nominated by New
England Business Trust and the voting obligation would be eliminated if New
England Business Trust holds less than 1,000,672 shares.

     New England Business Trust, Northeast Utilities and we also agreed under
the memorandum of understanding to use commercially reasonable efforts to cause
the form of stockholders agreement which is to be executed in connection with
the closing of the Consolidated Edison Communications and Exelon Corporation
agreements to be amended to add New England Business Trust as a party and to
provide for amendments similar to those to be made to the existing stockholders
agreement between New England Business Trust and Northeast Utilities, which are
described above.



                                      -12-
<PAGE>


     In addition, New England Business Trust and Northeast Utilities agreed
under the memorandum of understanding to vote in favor of the issuance of shares
to Consolidated Edison Communications and Exelon Corporation in connection with
our agreements with each of them in the event stockholder approval is required.

OTHER TRANSACTIONS

         Ms. Courage, a director of the company, is Managing Director at Credit
Suisse First Boston, which acts on a regular basis as our financial advisor and
provided a fairness opinion in connection with the agreements we entered into
with Consolidated Edison Corporation and Exelon Corporation.

         During the years ended December 31, 1997, 1998 and 1999, the company
reimbursed Central Maine Power Company and/or MaineCom Services for personnel
and construction costs related to our activities. The amount paid to Central
Maine Power Company totaled $725,000, $1.2 million and $241,000 for the years
ended December 31, 1997, 1998 and 1999, respectively. Of those amounts,$29,779
and $151,933 was included in accounts payable at December 31, 1997 and 1998
respectively.

         The Company paid Northeast Utilities $946,000 in 1997, $1,907,000 in
1998 and $1,159,000 in 1999 for materials, labor and other contractor charges
related to the construction of the NEON system. Approximately $494,500, $359,300
and $486,000 was included in accounts payable at December 31, 1997, 1998 and
1999, respectively.

REGISTRATION RIGHTS

         In November 1995, we entered into a Stock Subscription Agreement with
Mainecom Services pursuant to which MaineCom Services purchased shares of our
Series B Convertible Preferred Stock. Pursuant to the terms of the agreement,
MaineCom Services has the right to have the shares of Common Stock that were
issued upon conversion of its shares of Series B Convertible Preferred Stock
included in any registration statement we file relating to any public offering
of our Common Stock, except to the extent the number of such shares may be
limited by the managing underwriter of any such offering. In addition, MaineCom
Services may request that we register all or part of the those shares at any
time at least 180 days after the effective date of a registered underwritten
offering of our Common Stock, provided that the anticipated aggregate net
offering price for such securities is at least $10,000,000. MaineCom Services
through its affiliate, New England Business Trust, made such a demand by a
letter addressed to the company and dated January 28, 2000.

PRINCIPAL STOCKHOLDERS AGREEMENT

     Central Maine Power Company and Northeast Utilities have entered into a
Principal Stockholders Agreement dated May 28, 1998, whereby each such party
agrees that, following the completion of our initial public offering it will not
permit or cause the company to merge or consolidate, liquidate or dissolve,
change its form of organization or sell, lease, exchange or transfer all or
substantially all of its assets; or seek bankruptcy protection or certain other
protection from creditors, without the consent of both parties. In addition,
each of Northeast Utilities and Central Maine Power Company has rights of first
offer in connection with the proposed sale of our common stock held by the other
party and the option to purchase the shares of common stock held by the other
party if such other party seeks bankruptcy protection or similar relief. This
agreement will remain in effect for so long as Northeast Utilities owns at least
10% of our outstanding common stock, fully diluted; and the aggregate shares of
common stock owned by Northeast Utilities and Central Maine Power Company is at
least 33-1/3% of our outstanding common stock, on a fully diluted basis.

     For a description of employment agreements between the company and the
Named Executive Officers, see "Executive Compensation - Employment, Termination
and Change-in-Control Arrangements," above. For a description of stock options
granted to certain directors of the company, see "Compensation of Directors,"
above.

Comparative Stock Performance



                                      -13-
<PAGE>


     The following graph compares the cumulative total stockholder return on the
Common Stock between July 31, 1998 (the date our common stock commenced public
trading) and December 31, 1999 with the cumulative total return of the Nasdaq
(U.S.) Index and the Nasdaq Telephone Communications Index, over the same
period. This graph assumes the investment of $100 on July 31, 1998 in our common
stock, the Nasdaq U.S. Index and the Nasdaq Telecommunications Index, and
assumes any dividends are reinvested.

           Comparison of Seventeen Month Cumulative Total Return Among
                          NorthEast Optic Network, Inc.
                              The Nasdaq U.S. Index
                       The Nasdaq Telecommunications Index

Northeast Optic Network Inc (NOPT)


<TABLE>
<CAPTION>

                                                           CUMULATIVE TOTAL RETURN
                             -------------------------------------------------------------------------------------------------------
                                  7/98      8/98     9/98      10/98     11/98      12/98       1/99       2/99      3/99       4/99

<S>                             <C>        <C>      <C>        <C>       <C>        <C>       <C>        <C>       <C>        <C>
NORTHEAST OPTIC NETWORK, INC.   100.00     51.04    69.79      51.04     88.54      86.46     131.25     125.00    117.71     142.71

NASDAQ STOCK MARKET (U.S.)      100.00     80.18    91.30      95.32    105.00     118.64     135.86     123.67    132.98     137.24

NASDAQ TELECOMMUNICATIONS       100.00     75.51    85.10      92.94     98.47     117.60     135.82     134.26    146.14     154.15
</TABLE>


<TABLE>
<CAPTION>

                                                                 CUMULATIVE TOTAL RETURN
                               ---------------------------------------------------------------------------------------
                                      5/99      6/99       7/99       8/99       9/99     10/99      11/99      12/99
<S>                                 <C>       <C>        <C>        <C>        <C>       <C>        <C>        <C>
NORTHEAST OPTIC NETWORK, INC.       135.42    125.52     301.56     300.00     314.58    303.13     541.67     521.36

NASDAQ STOCK MARKET (U.S.)          133.58    145.50     142.93     148.90     149.03    160.66     179.43     219.57

NASDAQ TELECOMMUNICATIONS           155.99    155.36     151.56     145.05     144.01    170.51     177.79     204.80
</TABLE>



                                      -14-
<PAGE>

                                    SIGNATURES

     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this Amendment to its
Annual Report on Form 10-K/A to be signed on its behalf by the undersigned,
thereunto duly authorized, in Westborough, Massachusetts, on this 27th day of
April 2000.


                                    NORTHEAST OPTIC NETWORK, INC.


                                    By: /s/ Vincent C. Bisceglia
                                        ------------------------
                                        Vincent C. Bisceglia
                                        Chief Executive Officer and
                                        Chairman of the Board of Directors


     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, as amended, this Amendment to the Registrant's Annual
Report on Form 10-K/A has been signed by the following persons in the
capacities and on the dates indicated.

<TABLE>
<CAPTION>

        SIGNATURE                              TITLE                              DATE
        ---------                              -----                              ----
<S>                                    <C>                                   <C>
  /s/ Vincent C. Bisceglia             Chief Executive Officer and           April 27, 2000
-----------------------------       Chairman of the Board of Directors
    Vincent C. Bisceglia              (Principal Executive Officer)


                                       President and Vice Chairman           April 27, 2000
-----------------------------           of the Board of Directors
    Victor Colantonio


             *                          Vice President, Finance,             April 27, 2000
-----------------------------     Chief Financial Officer and Treasurer
    William F. Fennell             (Principal Financial and Accounting
                                                Officer)


-----------------------------                  Director                      April 27, 2000
   Katherine D. Courage

             *
-----------------------------                  Director                      April 27, 2000
     John W. Forsgren

             *
-----------------------------                  Director                      April 27, 2000
     Gary D. Simon

             *
-----------------------------                  Director                      April 27, 2000
   F. Michael McClain

             *
-----------------------------                  Director                      April 27, 2000
    Arthur Adelberg

</TABLE>


*By:   /s/ Vincent C. Bisceglia
    -------------------------------
         Vincent C. Bisceglia
           Attorney-in-fact
                                 -15-