MASERGY COMMUNICATIONS, INC. STOCK PURCHASE AGREEMENT

Exhibit 10.2C

MASERGY COMMUNICATIONS, INC.

STOCK PURCHASE AGREEMENT

AGREEMENT made as of this      day of             , 20    , by and between Masergy Communications, Inc., a Delaware corporation and                     , Optionee under the Corporation’s 2001 Stock Option/Stock Issuance Plan.

All capitalized terms in this Agreement shall have the meaning assigned to them in this Agreement or in the attached Appendix.

A. EXERCISE OF OPTION

1. Exercise. Optionee hereby purchases      shares of Common Stock (the “Purchased Shares”) pursuant to that certain option (the “Option”) granted Optionee on             , 200     (the “Grant Date”) to purchase up to      shares of Common Stock under the Plan at the exercise price of $          per share (the “Exercise Price”).

2. Payment. Concurrently with the delivery of this Agreement to the Corporation, Optionee shall pay the Exercise Price for the Purchased Shares in accordance with the provisions of the Option Agreement and shall deliver whatever additional documents may be required by the Option Agreement as a condition for exercise, together with a duly-executed blank Assignment Separate from Certificate (in the form attached hereto as Exhibit I) with respect to the Purchased Shares.

3. Escrow. The Corporation shall have the right to hold the certificates representing any Purchased Shares which are subject to the Repurchase Right in escrow.

4. Stockholder Rights. Until such time as the Corporation exercises the Repurchase Right or the First Refusal Right, Optionee (or any successor in interest) shall have all the rights of a stockholder (including voting, dividend and liquidation rights) with respect to the Purchased Shares, including any Purchased Shares held in escrow hereunder, subject, however, to the transfer restrictions of Articles B and C.

B. SECURITIES LAW COMPLIANCE

1. Restricted Securities. The Purchased Shares have not been registered under the 1933 Act and are being issued to Optionee in reliance upon the exemption from such registration provided by SEC Rule 701 for stock issuances under compensatory benefit plans such as the Plan. Optionee hereby confirms that Optionee has been informed that the Purchased Shares are restricted securities under the 1933 Act and may not be resold or transferred unless the Purchased Shares are first registered under the Federal securities laws or unless an exemption

from such registration is available. Accordingly, Optionee hereby acknowledges that Optionee is prepared to hold the Purchased Shares for an indefinite period and that Optionee is aware that SEC Rule 144 issued under the 1933 Act which exempts certain resales of unrestricted securities is not presently available to exempt the resale of the Purchased Shares from the registration requirements of the 1933 Act.

2. Restrictions on Disposition of Purchased Shares. Optionee shall make no disposition of the Purchased Shares (other than a Permitted Transfer) unless and until there is compliance with all of the following requirements:

(i) Optionee shall have provided the Corporation with a written summary of the terms and conditions of the proposed disposition.

(ii) Optionee shall have complied with all requirements of this Agreement applicable to the disposition of the Purchased Shares.

(iii) Optionee shall have provided the Corporation with written assurances, in form and substance satisfactory to the Corporation, that (a) the proposed disposition does not require registration of the Purchased Shares under the 1933 Act or (b) all appropriate action necessary for compliance with the registration requirements of the 1933 Act or any exemption from registration available under the 1933 Act (including Rule 144) has been taken.

The Corporation shall not be required (i) to transfer on its books any Purchased Shares which have been sold or transferred in violation of the provisions of this Agreement or (ii) to treat as the owner of the Purchased Shares, or otherwise to accord voting, dividend or liquidation rights to, any transferee to whom the Purchased Shares have been transferred in contravention of this Agreement.

3. Restrictive Legends. The stock certificates for the Purchased Shares shall be endorsed with the following restrictive legends:

(i) “The shares represented by this certificate have not been registered under the Securities Act of 1933. The shares may not be sold or offered for sale in the absence of (a) an effective registration statement for the shares under such Act, (b) a ‘no action’ letter of the Securities and Exchange Commission with respect to such sale or offer or (c) satisfactory assurances to the Corporation that registration under such Act is not required with respect to such sale or offer.”

(ii) “The shares represented by this certificate are unvested and are subject to certain repurchase rights and rights of first refusal granted to the Corporation and accordingly may not be sold, assigned, transferred, encumbered, or in any manner disposed of except in conformity with the terms of a written agreement dated             , 200     between the Corporation and the registered holder of the shares (or the predecessor in interest to the shares). A copy of such agreement is maintained at the Corporation’s principal corporate offices.”

2.

C. TRANSFER RESTRICTIONS

1. Restriction on Transfer. Except for any Permitted Transfer, Optionee shall not transfer, assign, encumber or otherwise dispose of any of the Purchased Shares which are subject to the Repurchase Right. In addition, Purchased Shares which are released from the Repurchase Right shall not be transferred, assigned, encumbered or otherwise disposed of in contravention of the First Refusal Right or the Market Stand-Off.

2. Transferee Obligations. Each person (other than the Corporation) to whom the Purchased Shares are transferred by means of a Permitted Transfer must, as a condition precedent to the validity of such transfer, acknowledge in writing to the Corporation that such person is bound by the provisions of this Agreement and that the transferred shares are subject to (i) the Repurchase Right, (ii) the First Refusal Right and (iii) the Market Stand-Off, to the same extent such shares would be so subject if retained by Optionee.

3. Market Stand-Off.

(a) In connection with any underwritten public offering by the Corporation of its equity securities pursuant to an effective registration statement filed under the 1933 Act, including the Corporation’s initial public offering, Owner shall not sell, make any short sale of, loan, hypothecate, pledge, grant any option for the purchase of, or otherwise dispose or transfer for value or otherwise agree to engage in any of the foregoing transactions with respect to, any Purchased Shares without the prior written consent of the Corporation or its underwriters. Such restriction (the “Market Stand-Off”) shall be in effect for such period of time from and after the effective date of the final prospectus for the offering as may be requested by the Corporation or such underwriters. In no event, however, shall such period exceed one hundred eighty (180) days and the Market Stand-Off shall in all events terminate two (2) years after the effective date of the Corporation’s initial public offering.

(b) Owner shall be subject to the Market Stand-Off provided and only if the officers and directors of the Corporation are also subject to similar restrictions.

(c) Any new, substituted or additional securities which are by reason of any Recapitalization or Reorganization distributed with respect to the Purchased Shares shall be immediately subject to the Market Stand-Off, to the same extent the Purchased Shares are at such time covered by such provisions.

(d) In order to enforce the Market Stand-Off, the Corporation may impose stop-transfer instructions with respect to the Purchased Shares until the end of the applicable stand-off period.

3.

D. REPURCHASE RIGHT

1. Grant. The Corporation is hereby granted the right (the “Repurchase Right”), exercisable at any time during the ninety (90)-day period following the date Optionee ceases for any reason to remain in Service or (if later) during the ninety (90)-day period following the execution date of this Agreement, to repurchase at the Exercise Price all or any portion of the Purchased Shares in which Optionee is not, at the time of his or her cessation of Service, vested in accordance with the Vesting Schedule (such shares to be hereinafter referred to as the “Unvested Shares”).

2. Exercise of the Repurchase Right. The Repurchase Right shall be exercisable by written notice delivered to each Owner of the Unvested Shares prior to the expiration of the ninety (90)-day exercise period. The notice shall indicate the number of Unvested Shares to be repurchased and the date on which the repurchase is to be effected, such date to be not more than thirty (30) days after the date of such notice. The certificates representing the Unvested Shares to be repurchased shall be delivered to the Corporation prior to the close of business on the date specified for the repurchase. Concurrently with the receipt of such stock certificates, the Corporation shall pay to Owner, in cash or cash equivalents (including the cancellation of any purchase-money indebtedness), an amount equal to the Exercise Price previously paid for the Unvested Shares which are to be repurchased from Owner.

3. Termination of the Repurchase Right. The Repurchase Right shall terminate with respect to any Unvested Shares for which it is not timely exercised under Paragraph D.2. In addition, the Repurchase Right shall terminate and cease to be exercisable with respect to any and all Purchased Shares in which Optionee vests in accordance with the Vesting Schedule. All Purchased Shares as to which the Repurchase Right lapses shall, however, remain subject to (i) the First Refusal Right and (ii) the Market Stand-Off.

4. Aggregate Vesting Limitation. If the Option is exercised in more than one increment so that Optionee is a party to one or more other Stock Purchase Agreements (the “Prior Purchase Agreements”) which are executed prior to the date of this Agreement, then the total number of Purchased Shares as to which Optionee shall be deemed to have a fully-vested interest under this Agreement and all Prior Purchase Agreements shall not exceed in the aggregate the number of Purchased Shares in which Optionee would otherwise at the time be vested, in accordance with the Vesting Schedule, had all the Purchased Shares (including those acquired under the Prior Purchase Agreements) been acquired exclusively under this Agreement.

5. Recapitalization. Any new, substituted or additional securities or other property (including cash paid other than as a regular cash dividend) which is by reason of any Recapitalization distributed with respect to the Purchased Shares shall be immediately subject to the Repurchase Right, but only to the extent the Purchased Shares are at the time covered by such right. Appropriate adjustments to reflect such distribution shall be made to the number and/or class of Purchased Shares subject to this Agreement and to the price per share to be paid upon the exercise of the Repurchase Right in order to reflect the effect of any such Recapitalization upon the Corporation’s capital structure; provided, however, that the aggregate purchase price shall remain the same. Any securities or other property (including cash) distributed with respect to the Purchased Shares may be held in escrow.

4.

6. Corporate Transaction.

(a) The Repurchase Right shall lapse immediately prior to the consummation of the Corporate Transaction except to the extent assigned to the successor corporation (or parent thereof) in connection with the Corporate Transaction.

(b) To the extent the Repurchase Right remains in effect following a Corporate Transaction, such right shall apply to the new capital stock or other property (including any cash payments) received in exchange for the Purchased Shares in consummation of the Corporate Transaction, but only to the extent the Purchased Shares are at the time covered by such right. Appropriate adjustments shall be made to the price per share payable upon exercise of the Repurchase Right to reflect the effect of the Corporate Transaction upon the Corporation’s capital structure; provided, however, that the aggregate purchase price shall remain the same. Any capital stock or other property (including any cash payments) received in exchange for the Purchased Shares may be held in escrow.

E. RIGHT OF FIRST REFUSAL

1. Grant. The Corporation is hereby granted the right of first refusal (the “First Refusal Right”), exercisable in connection with any proposed transfer of the Purchased Shares in which Optionee has vested in accordance with the Vesting Schedule. For purposes of this Article E, the term “transfer” shall include any sale, assignment, pledge, encumbrance or other disposition of the Purchased Shares intended to be made by Owner, but shall not include any Permitted Transfer.

2. Notice of Intended Disposition. In the event any Owner of Purchased Shares in which Optionee has vested desires to accept a bona fide third-party offer for the transfer of any or all of such shares (the Purchased Shares subject to such offer to be hereinafter referred to as the “Target Shares”), Owner shall promptly (i) deliver to the Corporation written notice (the “Disposition Notice”) of the terms of the offer, including the purchase price and the identity of the third-party offeror, and (ii) provide satisfactory proof that the disposition of the Target Shares to such third-party offeror would not be in contravention of the provisions set forth in Articles B and C.

3. Exercise of the First Refusal Right. The Corporation shall, for a period of forty-five (45) days following receipt of the Disposition Notice, have the right to repurchase any or all of the Target Shares subject to the Disposition Notice upon the same terms as those specified therein or upon such other terms (not materially different from those specified in the Disposition Notice) to which Owner consents. Such right shall be exercisable by delivery of written notice (the “Exercise Notice”) to Owner prior to the expiration of the forty-five (45)-day exercise period. If such right is exercised with respect to all the Target Shares, then the Corporation shall effect the repurchase of such shares, including payment of the purchase price, not more than fifteen (15) business days after delivery of the Exercise Notice; and at such time the certificates representing the Target Shares shall be delivered to the Corporation.

5.

Should the purchase price specified in the Disposition Notice be payable in property other than cash or evidences of indebtedness, the Corporation shall have the right to pay the purchase price in the form of cash equal in amount to the value of such property. If Owner and the Corporation cannot agree on such cash value within thirty (30) days after the Corporation’s receipt of the Disposition Notice, the valuation shall be made by an appraiser of recognized standing selected by Owner and the Corporation or, if they cannot agree on an appraiser within forty-five (45) days after the Corporation’s receipt of the Disposition Notice, each shall select an appraiser of recognized standing and the two (2) appraisers shall designate a third appraiser of recognized standing, whose appraisal shall be determinative of such value. The cost of such appraisal shall be shared equally by Owner and the Corporation. The closing shall then be held on the later of (i) the fifteenth (15th) business day following delivery of the Exercise Notice or (ii) the fifteenth (15th) business day after such valuation shall have been made.

4. Non-Exercise of the First Refusal Right. In the event the Exercise Notice is not given to Owner prior to the expiration of the forty-five (45)-day exercise period, Owner shall have a period of thirty (30) days thereafter in which to sell or otherwise dispose of the Target Shares to the third-party offeror identified in the Disposition Notice upon terms (including the purchase price) no more favorable to such third-party offeror than those specified in the Disposition Notice; provided, however, that any such sale or disposition must not be effected in contravention of the provisions of Article B and Paragraph C.3. The third-party offeror shall acquire the Target Shares free and clear of the Repurchase Right and the First Refusal Right, but the acquired shares shall remain subject to Article B and Paragraph C.3. In the event Owner does not effect such sale or disposition of the Target Shares within the specified thirty (30)-day period, the First Refusal Right shall continue to be applicable to any subsequent disposition of the Target Shares by Owner until such right lapses.

5. Partial Exercise of the First Refusal Right. In the event the Corporation makes a timely exercise of the First Refusal Right with respect to a portion, but not all, of the Target Shares specified in the Disposition Notice, Owner shall have the option, exercisable by written notice to the Corporation delivered within fifteen (15) business days after Owner’s receipt of the Exercise Notice, to effect the sale of the Target Shares pursuant to either of the following alternatives:

(i) sale or other disposition of all the Target Shares to the third-party offeror identified in the Disposition Notice, but in full compliance with the requirements of Paragraph E.4, as if the Corporation did not exercise the First Refusal Right; or

(ii) sale to the Corporation of the portion of the Target Shares which the Corporation has elected to purchase, such sale to be effected in substantial conformity with the provisions of Paragraph E.3. The First Refusal Right shall continue to be applicable to any subsequent disposition of the remaining Target Shares until such right lapses.

6.

Failure of Owner to deliver timely notification to the Corporation shall be deemed to be an election by Owner to sell the Target Shares pursuant to alternative (i) above.

6. Recapitalization/Reorganization.

(a) Any new, substituted or additional securities or other property which is by reason of any Recapitalization distributed with respect to the Purchased Shares shall be immediately subject to the First Refusal Right, but only to the extent the Purchased Shares are at the time covered by such right.

(b) In the event of a Reorganization, the First Refusal Right shall remain in full force and effect and shall apply to the new capital stock or other property received in exchange for the Purchased Shares in consummation of the Reorganization, but only to the extent the Purchased Shares are at the time covered by such right.

7. Lapse. The First Refusal Right shall lapse upon the earliest to occur of (i) the first date on which shares of the Common Stock are held of record by more than five hundred (500) persons, (ii) a determination is made by the Board that a public market exists for the outstanding shares of Common Stock or (iii) a firm commitment underwritten public offering, pursuant to an effective registration statement under the 1933 Act, covering the offer and sale of the Common Stock in the aggregate amount of at least ten million dollars ($10,000,000). However, the Market Stand-Off shall continue to remain in full force and effect following the lapse of the First Refusal Right.

F. SPECIAL TAX ELECTION

The acquisition of the Purchased Shares may result in adverse tax consequences which may be avoided or mitigated by filing an election under Code Section 83(b). Such election must be filed within thirty (30) days after the date of this Agreement. A description of the tax consequences applicable to the acquisition of the Purchased Shares and the form for making the Code Section 83(b) election are set forth in Exhibit II. OPTIONEE SHOULD CONSULT WITH HIS OR HER TAX ADVISOR TO DETERMINE THE TAX CONSEQUENCES OF ACQUIRING THE PURCHASED SHARES AND THE ADVANTAGES AND DISADVANTAGES OF FILING THE CODE SECTION 83(b) ELECTION. OPTIONEE ACKNOWLEDGES THAT IT IS OPTIONEE’S SOLE RESPONSIBILITY, AND NOT THE CORPORATION’S, TO FILE A TIMELY ELECTION UNDER CODE SECTION 83(b), EVEN IF OPTIONEE REQUESTS THE CORPORATION OR ITS REPRESENTATIVES TO MAKE THIS FILING ON HIS OR HER BEHALF.

7.

G. GENERAL PROVISIONS

1. Assignment. The Corporation may assign the Repurchase Right and/or the First Refusal Right to any person or entity selected by the Board, including (without limitation) one or more stockholders of the Corporation.

2. No Employment or Service Contract. Nothing in this Agreement or in the Plan shall confer upon Optionee any right to continue in Service for any period of specific duration or interfere with or otherwise restrict in any way the rights of the Corporation (or any Parent or Subsidiary employing or retaining Optionee) or of Optionee, which rights are hereby expressly reserved by each, to terminate Optionee’s Service at any time for any reason, with or without cause.

3. Notices. Any notice required to be given under this Agreement shall be in writing and shall be deemed effective upon personal delivery or upon deposit in the U.S. mail, registered or certified, postage prepaid and properly addressed to the party entitled to such notice at the address indicated below such party’s signature line on this Agreement or at such other address as such party may designate by ten (10) days advance written notice under this paragraph to all other parties to this Agreement.

4. No Waiver. The failure of the Corporation in any instance to exercise the Repurchase Right or the First Refusal Right shall not constitute a waiver of any other repurchase rights and/or rights of first refusal that may subsequently arise under the provisions of this Agreement or any other agreement between the Corporation and Optionee. No waiver of any breach or condition of this Agreement shall be deemed to be a waiver of any other or subsequent breach or condition, whether of like or different nature.

5. Cancellation of Shares. If the Corporation shall make available, at the time and place and in the amount and form provided in this Agreement, the consideration for the Purchased Shares to be repurchased in accordance with the provisions of this Agreement, then from and after such time, the person from whom such shares are to be repurchased shall no longer have any rights as a holder of such shares (other than the right to receive payment of such consideration in accordance with this Agreement). Such shares shall be deemed purchased in accordance with the applicable provisions hereof, and the Corporation shall be deemed the owner and holder of such shares, whether or not the certificates therefor have been delivered as required by this Agreement.

6. Optionee Undertaking. Optionee hereby agrees to take whatever additional action and execute whatever additional documents the Corporation may deem necessary or advisable in order to carry out or effect one or more of the obligations or restrictions imposed on either Optionee or the Purchased Shares pursuant to the provisions of this Agreement.

7. Governing Law. This Agreement shall be governed by, and construed in accordance with, the laws of the State of Texas without resort to that State’s conflict-of-laws rules.

8.

8. Successors and Assigns. The provisions of this Agreement shall inure to the benefit of, and be binding upon, the Corporation and its successors and assigns and upon Optionee, Optionee’s permitted assigns and the legal representatives, heirs and legatees of Optionee’s estate, whether or not any such person shall have become a party to this Agreement and have agreed in writing to join herein and be bound by the terms hereof.

IN WITNESS WHEREOF, the parties have executed this Agreement on the day and year first indicated above.

9.

EXHIBIT I

ASSIGNMENT SEPARATE FROM CERTIFICATE

FOR VALUE RECEIVED              hereby sell(s), assign(s) and transfer(s) unto Masergy Communications, Inc. (the “Corporation”),                      (    ) shares of the Common Stock of the Corporation standing in his or her name on the books of the Corporation represented by Certificate No.                      herewith and do(es) hereby irrevocably constitute and appoint                      Attorney to transfer the said stock on the books of the Corporation with full power of substitution in the premises.

Dated:                     

Instruction: Please do not fill in any blanks other than the signature line. Please sign exactly as you would like your name to appear on the issued stock certificate. The purpose of this assignment is to enable the Corporation to exercise the Repurchase Right without requiring additional signatures on the part of Optionee.

EXHIBIT II

FEDERAL INCOME TAX CONSEQUENCES

AND SECTION 83(b) TAX ELECTION

I. Federal Income Tax Consequences and Section 83(b) Election For Exercise of Non-Statutory Option. If the Purchased Shares are acquired pursuant to the exercise of a Non-Statutory Option, as specified in the Grant Notice, then under Code Section 83, the excess of the Fair Market Value of the Purchased Shares on the date any forfeiture restrictions applicable to such shares lapse over the Exercise Price paid for such shares will be reportable as ordinary income on the lapse date. For this purpose, the term “forfeiture restrictions” includes the right of the Corporation to repurchase the Purchased Shares pursuant to the Repurchase Right. However, Optionee may elect under Code Section 83(b) to be taxed at the time the Purchased Shares are acquired, rather than when and as such Purchased Shares cease to be subject to such forfeiture restrictions. Such election must be filed with the Internal Revenue Service within thirty (30) days after the date of the Agreement. Even if the Fair Market Value of the Purchased Shares on the date of the Agreement equals the Exercise Price paid (and thus no tax is payable), the election must be made to avoid adverse tax consequences in the future. The form for making this election is attached as part of this exhibit. FAILURE TO MAKE THIS FILING WITHIN THE APPLICABLE THIRTY (30)-DAY PERIOD WILL RESULT IN THE RECOGNITION OF ORDINARY INCOME BY OPTIONEE AS THE FORFEITURE RESTRICTIONS LAPSE.

II. Federal Income Tax Consequences and Conditional Section 83(b) Election For Exercise of Incentive Option. If the Purchased Shares are acquired pursuant to the exercise of an Incentive Option, as specified in the Grant Notice, then the following tax principles shall be applicable to the Purchased Shares:

(i) For regular tax purposes, no taxable income will be recognized at the time the Option is exercised.

(ii) The excess of (a) the Fair Market Value of the Purchased Shares on the date the Option is exercised or (if later) on the date any forfeiture restrictions applicable to the Purchased Shares lapse over (b) the Exercise Price paid for the Purchased Shares will be includible in Optionee’s taxable income for alternative minimum tax purposes.

(iii) If Optionee makes a disqualifying disposition of the Purchased Shares, then Optionee will recognize ordinary income in the year of such disposition equal in amount to the excess of (a) the Fair Market Value of the Purchased Shares on the date the Option is exercised or (if later) on the date any forfeiture restrictions applicable to the Purchased Shares lapse over (b) the Exercise Price paid for the Purchased Shares. Any additional gain recognized upon the disqualifying disposition will be either short-term or long-term capital gain depending upon the period for which the Purchased Shares are held prior to the disposition.

II-1

(iv) For purposes of the foregoing, the term “forfeiture restrictions” will include the right of the Corporation to repurchase the Purchased Shares pursuant to the Repurchase Right. The term “disqualifying disposition” means any sale or other disposition ¹ of the Purchased Shares within two (2) years after the Grant Date or within one (1) year after the exercise date of the Option.

(v) Optionee may, in connection with the exercise of the Option for any Purchased Shares at the time subject to forfeiture restrictions, file a protective election under Code Section 83(b) which would limit Optionee’s alternative minimum taxable income upon exercise to the excess of the Fair Market Value of the Purchased Shares on the date the Option is exercised over the Exercise Price paid for the Purchased Shares. In the absence of final Treasury Regulations relating to Incentive Options, it is not certain whether Optionee may similarly file a protective election under Section 83(b) which would limit Optionee’s ordinary income upon a disqualifying disposition to the excess of the Fair Market Value of the Purchased Shares on the date the Option is exercised over the Exercise Price paid for the Purchased Shares. Accordingly, such election if properly filed will only be allowed to the extent the final Treasury Regulations permit such a protective election. Page 2 of the attached form for making the election should be filed with any election made in connection with the exercise of an Incentive Option.

II-2

SECTION 83(b) ELECTION

This statement is being made under Section 83(b) of the Internal Revenue Code, pursuant to Treas. Reg. Section 1.83-2.

Name:

Address:

Taxpayer Ident. No.:

This election must be filed with the Internal Revenue Service Center with which taxpayer files his or her Federal income tax returns and must be made within thirty (30) days after the execution date of the Stock Purchase Agreement. This filing should be made by registered or certified mail, return receipt requested. Optionee must retain two (2) copies of the completed form for filing with his or her Federal and state tax returns for the current tax year and an additional copy for his or her records.

1.

The property described in the above Section 83(b) election is comprised of shares of common stock acquired pursuant to the exercise of an incentive stock option under Section 422 of the Internal Revenue Code (the “Code”). Accordingly, it is the intent of the Taxpayer to utilize this election to achieve the following tax results:

1. The purpose of this election is to have the alternative minimum taxable income attributable to the purchased shares measured by the amount by which the fair market value of such shares at the time of their transfer to the Taxpayer exceeds the purchase price paid for the shares. In the absence of this election, such alternative minimum taxable income would be measured by the spread between the fair market value of the purchased shares and the purchase price which exists on the various lapse dates in effect for the forfeiture restrictions applicable to such shares. The election is to be effective to the full extent permitted under the Code.

2. Section 421(a)(1) of the Code expressly excludes from income any excess of the fair market value of the purchased shares over the amount paid for such shares. Accordingly, this election is also intended to be effective in the event there is a “disqualifying disposition” of the shares, within the meaning of Section 421(b) of the Code, which would otherwise render the provisions of Section 83(a) of the Code applicable at that time. Consequently, the Taxpayer hereby elects to have the amount of disqualifying disposition income measured by the excess of the fair market value of the purchased shares on the date of transfer to the Taxpayer over the amount paid for such shares. Since Section 421(a) presently applies to the shares which are the subject of this Section 83(b) election, no taxable income is actually recognized for regular tax purposes at this time, and no income taxes are payable, by the Taxpayer as a result of this election.

THIS PAGE 2 IS TO BE ATTACHED TO ANY SECTION 83(b) ELECTION FILED IN CONNECTION WITH THE EXERCISE OF AN INCENTIVE STOCK OPTION UNDER THE FEDERAL TAX LAWS.

2.

APPENDIX

The following definitions shall be in effect under the Agreement:

A. Agreement shall mean this Stock Purchase Agreement.

B. Board shall mean the Corporation’s Board of Directors.

C. Code shall mean the Internal Revenue Code of 1986, as amended.

D. Common Stock shall mean the Corporation’s common stock.

E. Corporate Transaction shall mean either of the following stockholder-approved transactions:

(i) a merger, consolidation or other reorganization approved by the Corporation’s stockholders, unless securities representing more than fifty percent (50%) of the total combined voting power of the voting securities of the successor corporation are immediately thereafter beneficially owned, directly or indirectly and in substantially the same proportion, by the persons who beneficially owned the Corporation’s outstanding voting securities immediately prior to such transaction, or

(ii) the sale, transfer or other disposition of all or substantially all of the Corporation’s assets in complete liquidation or dissolution of the Corporation.

F. Corporation shall mean Masergy Communications, Inc., a Delaware corporation.

G. Disposition Notice shall have the meaning assigned to such term in Paragraph E2.

H. Exercise Notice shall have the meaning assigned to such term in Paragraph E.3.

I. Exercise Price shall have the meaning assigned to such term in Paragraph A.1.

J. Fair Market Value of a share of Common Stock on any relevant date, prior to the initial public offering of the Common Stock, shall be determined by the Plan Administrator after taking into account such factors as it shall deem appropriate.

K. First Refusal Right shall mean the right granted to the Corporation in accordance with Article E.

L. Grant Date shall have the meaning assigned to such term in Paragraph A.1.

M. Grant Notice shall mean the Notice of Grant of Stock Option pursuant to which Optionee has been informed of the basic terms of the Option.

A-1.

N. Incentive Option shall mean an option which satisfies the requirements of Code Section 422.

O. Market Stand-Off shall mean the market stand-off restriction specified in Paragraph C.3.

P. 1933 Act shall mean the Securities Act of 1933, as amended.

Q. Non-Statutory Option shall mean an option not intended to satisfy the requirements of Code Section 422.

R. Option shall have the meaning assigned to such term in Paragraph A.1.

S. Option Agreement shall mean all agreements and other documents evidencing the Option.

T. Optionee shall mean the person to whom the Option is granted under the Plan.

U. Owner shall mean Optionee and all subsequent holders of the Purchased Shares who derive their chain of ownership through a Permitted Transfer from Optionee.

V. Parent shall mean any corporation (other than the Corporation) in an unbroken chain of corporations ending with the Corporation, provided each corporation in the unbroken chain (other than the Corporation) owns, at the time of the determination, stock possessing fifty percent (50%) or more of the total combined voting power of all classes of stock in one of the other corporations in such chain.

W. Permitted Transfer shall mean (i) a gratuitous transfer of the Purchased Shares, provided and only if Optionee obtains the Corporation’s prior written consent to such transfer, (ii) a transfer of title to the Purchased Shares effected pursuant to Optionee’s will or the laws of intestate succession following Optionee’s death or (iii) a transfer to the Corporation in pledge as security for any purchase-money indebtedness incurred by Optionee in connection with the acquisition of the Purchased Shares.

X. Plan shall mean the Corporation’s 2001 Stock Option/Stock Issuance Plan.

Y. Plan Administrator shall mean either the Board or a committee of Board members, to the extent the committee is at the time responsible for administration of the Plan.

Z. Prior Purchase Agreement shall have the meaning assigned to such term in Paragraph D.4.

AA. Purchased Shares shall have the meaning assigned to such term in Paragraph A.1.

A-2.

BB. Recapitalization shall mean any stock split, stock dividend, recapitalization, combination of shares, exchange of shares or other change affecting the Corporation’s outstanding Common Stock as a class without the Corporation’s receipt of consideration.

CC. Reorganization shall mean any of the following transactions:

(i) a merger or consolidation in which the Corporation is not the surviving entity,

(ii) a sale, transfer or other disposition of all or substantially all of the Corporation’s assets,

(iii) a reverse merger in which the Corporation is the surviving entity but in which the Corporation’s outstanding voting securities are transferred in whole or in part to a person or persons different from the persons holding those securities immediately prior to the merger, or

(iv) any transaction effected primarily to change the state in which the Corporation is incorporated or to create a holding company structure.

DD. Repurchase Right shall mean the right granted to the Corporation in accordance with Article D.

EE. SEC shall mean the Securities and Exchange Commission.

FF. Service shall mean Optionee’s provision of services to the Corporation (or any Parent or Subsidiary) in the capacity of an employee, subject to the control and direction of the employer entity as to both the work to be performed and the manner and method of performance, a non-employee member of the board of directors or a consultant or independent advisor.

GG. Subsidiary shall mean any corporation (other than the Corporation) in an unbroken chain of corporations beginning with the Corporation, provided each corporation (other than the last corporation) in the unbroken chain owns, at the time of the determination, stock possessing fifty percent (50%) or more of the total combined voting power of all classes of stock in one of the other corporations in such chain.

HH. Target Shares shall have the meaning assigned to such term in Paragraph E.2.

II. Vesting Schedule shall mean the vesting schedule specified in the Grant Notice, subject to the acceleration provisions upon an Involuntary Termination following a Corporate Transaction.

JJ. Unvested Shares shall have the meaning assigned to such term in Paragraph D.1.

A-3.