Arbinet Holdings, Inc.

                           33 Whitehall St, 19th floor

                                  New York, NY


                                                                March 29th, 2000


Mr J. Curt Hockemeier

3 Peacan Valley Court

Skillman, NJ 08558

Tel#: (609) 466-1260


Dear Curt,


On behalf of Arbinet Holdings, Inc. (the "Company"), I am pleased to extend to

you an offer of employment in accordance with the following terms:


     1.   Title and Position. Effective immediately following your acceptance of

          this offer you will serve as an executive of the Company, initially as

          President and Chief Operating Officer of the Company. After an initial

          period, not to exceed year end, December 31, 2000, you will be

          appointed to the position of Chief Executive Officer. You will report

          to the Chief Executive Officer and Chairman of the Board of Directors

          of the Company until your appointment as Chief Executive Officer;

          thereafter, you will report to the Board of Directors.


     2.   Duties and Obligations. During your employment, you will devote your

          full business time, interest and effort to the performance of your

          duties with the Company. You will have during the initial period as

          President and COO, all of the functions of the Company reporting to

          you other than the Founder, Finance, Business Development and Legal.

          Subsequent to your appointment as Chief Executive Officer, these

          functions will also report to you.


     3.   Employment Relationship. Should you decide to accept the Company's

          offer, your employment will be "at-will" and your employment may be

          terminated by either you or the Company at any time for any reason (or

          no reason), by providing sixty (60) days prior written notice to the

          other party. Further, your participation in any Company benefit or

          equity program does not constitute an agreement by the Company to

          employ or continue to employ you for any period of time.


     4.   Salary. While you are employed on a full-time basis by the Company,

          the Company will pay you abase salary, which annualizes to $300,000,

          payable in accordance with the usual payroll practices of the Company

          including the withholding of all income and




J. Curt Hockemeier - Offer Letter

March 29, 2000

Page 2 of 5


          employment taxes. You will receive a one time "sign-on" bonus of

          $200,000 upon commencement of employment, payable pursuant to your

          instructions. At the time of your appointment as Chief Executive

          Officer, your salary will be increased to $400,000 annually.

          Thereafter, your base salary will be reviewed by the Compensation

          Committee of the Board of Directors on an annual basis and may be

          subject to adjustment upward based on various factors including,

          without limitation, your performance and the Company's achievement of

          its business plan (as determined by the Board of Directors).


     5.   Equity.


          (a)  The Board of Directors (or a duly authorized committee thereof)

               will grant to you, in the form of stock options ("Options"), the

               right to purchase 1,200,000 shares of Common Stock of the

               Company, at the lowest available employee plan price as of the

               acceptance of this offer (the current employee plan exercise

               price as approved by the Board of Directors on March 12th, 1999

               is approximately $5.71), subject to minor adjustments to the

               capitalization table and the following vesting schedule: such

               Options will become exercisable as to l/48th of the Options on

               the last day of each full month you are employed by the Company

               (the "Vesting Dates"), provided you are employed by the Company

               on the applicable Vesting Dates. To the maximum extent

               permissible, these will be incentive stock option as defined by

               the Internal Revenue Code of 1986, as amended (the "Code"), and

               the Arbinet Holdings, Inc. 1997 Stock Incentive Plan (the "Stock



          (b)  At your option, you will be provided with a loan to acquire the

               Option shares at the current option price. The vesting schedule

               will be replaced by an agreement for the Company to repurchase

               the unvested shares at the exercise price. This agreement for

               repurchase will expire as to the option to repurchase at the rate

               of 1/48th of the shares per month. In the event you elect this

               option, the original Option shares will be vested co-incident

               with the execution of the loan agreement and repurchase option

               granted by you to the Company to permit your immediate purchase.


          (c)  Except as otherwise provided in the Stock Plan and Section 7

               below, you shall forfeit to the Company (without compensation)

               all unvested Options on the date your employment with the Company



          (d)  If you have not been appointed as Chief Executive Officer, then

               in the event of termination of your employment by the Company in

               the 12 months following a change of control of more than 50% of

               the Company's voting stock, other than an IPO (a "Change of

               Control"), all unvested options will accelerate, and become

               exercisable or, alternatively, all repurchase rights will expire

               (collectively, the "Acceleration"). If you have been appointed as

               Chief Executive Officer, then Acceleration will occur upon a

               Change of Control.


          (e)  Following a termination of employment you will have six (6)

               months to exercise all vested options unless a longer period is

               provided in the stock option plan or agreement.




J. Curt Hockemeier - Offer Letter


March 29, 2000

Page 3 of 5


     6.   Benefits. You will participate, to the extent you are eligible and

          subject to confirming coverage with the applicable underwriter (if

          any), in all of the Company's employee benefit programs generally

          provided to the other executive officers, in accordance with the terms

          thereof as in effect from time to time; provided that your annual

          vacation shall not exceed 4 weeks.


     7.   Termination of Employment.


          (a)  In the event your employment hereunder is terminated by the

               Company without cause or by you for Good Reason (as defined

               below), the Company will pay you, subject to your compliance with

               Sections 8 and 9 below, (i) any unpaid base salary through the

               date of termination and any accrued vacation pay; (ii) severance

               pay equal to twelve (12) months' base salary at the rate in

               effect on the date of termination; (iii) an amount reimbursing

               you for the applicable premium payment for any COBRA coverage

               payable under a Company health or welfare plan for you and your

               dependents during the twelve (12) month period following the date

               of termination (the "Twelve Month Period"); and (iv) an amount

               equal to any employer contribution that would have been made by

               the Company to any retirement plan of the Company on your behalf

               had you remained employed by the Company during the Twelve Month

               Period assuming you contributed the maximum amount to such plan.

               Notwithstanding the foregoing, the amounts paid to you pursuant

               to subsections (iii) and (iv) of this Section 7(a) shall not

               exceed $25,000. In addition, if your employment is terminated by

               the Company without cause or by you for Good Reason under the

               provisions this Section 7, you will be granted accelerated

               vesting of 16/48ths of the option share grant, or accelerated

               expiration of 16/48ths of the repurchase rights whichever is



          (b)  In the event your employment hereunder is terminated for any

               other reason, the Company will pay you any unpaid base salary and

               compensation for accrued vacation through the date of



     In addition, in all termination events, except as specifically provided in

     Section 5 hereof, the Company will pay you any other amounts or benefits

     owing to you under the then applicable employee benefit plans and programs

     of the Company in accordance with such plans and programs. For purposes of

     this letter "cause" shall mean any of the following: (w) your willful

     misconduct in the performance of your duties to the Company, or your

     willful failure to implement any legal policy of the Company, (x)

     conviction of or plea of guilty or any other plea other than "not guilty"

     to a felony; (y) the violation by you of any material provision of this

     letter which either is not cured within ten days after a written notice is

     given to you by the Company or constitutes a habitual breach; or (z) your

     dishonesty, misappropriation or fraud with regard to the property of the

     Company or its affiliates.


     You may terminate your employment for Good Reason. "Good Reason" means,

     without your written consent: (i) a material adverse change in your title

     or the duties assigned to you; (ii) any material failure by the Company to

     comply with the provisions of this Agreement; or (iii) any requirement by

     the Company that your primary office location be other than in the states

     of New York, New Jersey or Connecticut.




J. Curt Hockemeier - Offer Letter

March 29, 2000

Page 4 of 5


     8.   Confidential Information. While providing your services, you will have

          access to and will obtain confidential information as to the Company,

          its affiliates, its employees and its customers and you may during the

          course of your employment develop certain information, inventions or

          other intellectual property. As a condition of your employment with

          the Company, you will be required to enter into the Company's Employee

          Inventions and Confidentiality Agreement (the "Confidentiality

          Agreement") The Confidentiality Agreement exists to assure the Company

          and its investors that the Company's valuable intellectual property

          and its rights thereto are protected.


     9.   Non-Competition/Non-Solicitation. (a) You agree that during your

          employment and for a period following the date your employment

          terminates of (i) two (2) years if your employment is terminated by

          the Company for cause or by you without Good Reason or (ii) one (1)

          year if your employment is terminated for any other reason, as the

          case may be, (the "Restricted Period"), you will not enter into

          Competition with the Company. "Competition" shall mean participating,

          directly or indirectly, as an individual proprietor, partner,

          stockholder, officer, employee, director, joint venturer, investor,

          lender, consultant or in any capacity whatsoever in a business in

          competition with any business conducted by the Company or its

          affiliates (a "Competitor") in any jurisdiction where the Company

          and/or its affiliates conduct as of the date your employment

          terminates such business, which shall be deemed to include, without

          limitation, any business activity or j jurisdiction which is covered

          by or included in a written proposal of business plan existing on the

          date of the termination; provided, however, that such participation

          shall not include (i) the mere ownership of not more than one percent

          (1%) of the total outstanding stock of a publicly-held company; (ii)

          the performance of services for any enterprise to the extent such

          services are not performed, directly or indirectly, for a business

          unit of the enterprise in the aforesaid Competition; or (iii) any

          activity engaged in with the prior written approval of the Board.


          (a)  You agree that, during the Restricted Period, you will not,

               directly or indirectly (i) solicit, recruit or hire any

               non-administrative or non-clerical employee of the Company for

               the purpose of being employed by you or by any Competitor of the

               Company on whose behalf you are acting as an agent,

               representative or employee and that you will not convey any

               confidential information or trade secrets about other employees

               of the Company to any other person or (ii) influence or attempt

               to influence customers or suppliers of the Company or its

               affiliates to direct their business to any Competitor of the



          (b)  You acknowledge that Sections 8 and 9 above are reasonable and

               necessary for the protection of the business of the Company and

               its affiliates and that part of the compensation to be paid under

               this letter is in consideration for the provisions contained in

               Sections 8 and 9. If any restriction set forth with regard to

               competition or solicitation of employees or customers is found by

               any court of competent jurisdiction to be unenforceable because

               it extends for too long a period of time or over too great a

               range of activities or over too broad a geographic area, it shall

               be interpreted to extend over a maximum period of time, range of

               activities or geographic area as to which it may be enforceable.

               You further acknowledge and consent that the Company would by

               reason of such




J. Curt Hockemeier - Offer Letter

March 29, 2000

Page 5 of 5


               competition or solicitation of employees or customers be entitled

               to injunctive relief in a court of appropriate jurisdiction

               prohibiting you from competing with the Company or its affiliates

               or engaging in solicitation in violation of this letter.


     10.  Governing Law/Miscellaneous. This letter is subject to the laws of the

          State of New York. This letter, along with the Confidentiality

          Agreement, sets forth the terms of your employment with the Company

          and supercedes all prior agreements, arrangements and communications,

          whether oral or written, between the Company and you. This letter may

          not be altered, modified, or amended except by written instrument

          signed by an individual authorized to sign of behalf of the Company

          (other than you) and by you. This letter may not be assigned in whole

          or in part, except that the Company may assign it to an acquiror of

          all or substantially all of the assets of the Company. This letter

          shall be binding on the successors and permitted assignees of the

          parties hereto. Except with regard to disputes arising under Section 8

          or 9 hereof, any dispute arising hereunder will be submitted to a

          neutral arbitrator selected by the parties. Such arbitrator shall

          conduct such arbitration in New York City under the rules of the

          American Arbitration Association. The Company will reimburse you for

          reasonable fees and expenses incurred by you in conjunction with this

          offer letter, up to $5,000.


This offer is made to you based on your representation to the Company that your

acceptance of employment with the Company and performance of the contemplated

services does not and will not conflict with or result in any breach or default

under, any agreement, contract or arrangement to which you are a party or

violate any other legal restriction. If you find this offer of employment

acceptable, please sign the enclosed copy of this letter and return it to us.


                                         Very truly yours,


                                         Arbiner Holdings, Inc.



                                         By: /s/ Anthony L. Craig


                                         Name: Anthony L. Craig

                                         Title: Chairman and Chief Executive




Agreed and Accepted:


/s/ J. Curt Hockemeier


J. Curt Hockemeier


Dated: April 4, 2000