PLEDGE AND SECURITY AGREEMENT

Exhibit 99.2

PLEDGE AND SECURITY AGREEMENT

THIS PLEDGE AND SECURITY AGREEMENT (this “ Agreement ”) is entered into as of April 16, 2007 by and between Wells Advisory Services I, LLC , a Georgia limited liability company (“ Pledgor ”), Wells Real Estate Investment Trust, Inc. , a Maryland corporation (“ REIT ”), WRT Acquisition Company, LLC , a Georgia limited liability company (“ REIT Sub ”), WGS Acquisition Company, LLC , a Georgia limited liability company (“ REIT GS Sub ” and, collectively with REIT, REIT Sub and the respective successors and assigns of REIT, REIT Sub and REIT GS Sub, “ Secured Party ”).

WHEREAS , Secured Party and Pledgor, among other parties, have entered into that certain Agreement and Plan of Merger, dated as of February 2, 2007 (as the same may be amended or modified in accordance with its terms, the “ Merger Agreement ”), pursuant to which, among other things, Pledgor has agreed to indemnify the Secured Party on the terms and conditions set forth in the Merger Agreement;

WHEREAS , pursuant to the Merger Agreement, Pledgor is required to execute and deliver this Agreement and to pledge and grant a continuing security interest in the Collateral (as defined herein) as additional security for the Secured Obligations (as defined herein);

WHEREAS , concurrent with the execution of this Agreement, the parties will enter into a Custodian Agreement with SunTrust Bank (the “Custodian”) pursuant to which the Custodian will act as custodian with respect to the Pledged Shares (as defined herein);

WHEREAS , all capitalized terms used herein which are not defined herein shall have the meanings ascribed to them in the Merger Agreement.

NOW, THEREFORE , in consideration of the foregoing and of the mutual covenants and agreements hereinafter set forth, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto hereby agree as follows:

For the purposes of this Agreement:

(a) “ Collateral ” means (i) (A) during the period (the “ Lock-Up Period ”) of eighteen (18) months commencing on the date of this Agreement, an aggregate of 19,546,302 REIT Common Shares issued by the Secured Party to the Pledgor pursuant to the Merger Agreement (the “ Pledged Shares ”); provided, that, in the case of any spilt or combination of REIT Common Shares or other recapitalization, the Pledged Shares shall constitute the securities into which the previously-outstanding Pledged Shares are converted or otherwise changed, (B) during the period of six (6) months following the end of the Lock-Up Period (the “ Follow-On Period ”), the Follow-On Collateral, and (C) following the end of the Follow-On Period, the Remaining Collateral; (ii) except as provided in Section 3(a)(ii), any dividends or distributions, distributions in property or other distributions made on or with respect to any of the Pledged Shares constituting Collateral in clause (i)(A) above and, if applicable, any Follow-On Collateral in clause (i)(B) and/or any Remaining Collateral in clause (i)(C) above; (iii) any money or other property paid to Secured Party pursuant to Section 3(b); (iv) any Replacement Assurances, as defined in, and provided pursuant to, Section 4; (v) all new, substituted and/or additional shares or other securities issued upon conversion or exchange of or by reason of any stock dividend, reclassification, readjustment, stock split or other change declared or made with respect to the Collateral in clauses (i)—(iv) above, or any warrants or any other rights, options or securities issued in respect of such Collateral; and (vi) all proceeds of the foregoing. The Collateral shall not include the 22,339 REIT Common Shares issued to Wells Capital, Inc. pursuant to Section 2.12 of the Merger Agreement.

(b) “ Event of Default ” means (i) any failure by Pledgor to fully pay or perform one or more of its obligations pursuant to Sections 7.3 or 8.2 of the Merger Agreement (collectively, the “ Secured Obligations ”), as

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determined by at least a majority of all of REIT’s disinterested directors who are non-employee directors, regardless of whether Secured Party has exercised its rights under Sections 7.3 or 8.2 of the Merger Agreement except that, if the obligation is disputed in good faith by Pledgor by notice given to Secured Party before the close of business on the tenth Business Day after Pledgor’s receipt of notice of such determination, Pledgor shall be deemed in default only if it fails to pay or perform within ten (10) Business Days after agreeing to do so or after being ordered to do so by an arbitration ruling or a court of competent jurisdiction pursuant to a judgment, order or decree that becomes final and non-appealable; (ii) the unenforceability of the Secured Party’s security interest in the Collateral with the priority set forth herein for any reason whatsoever (other than as a result of Secured Party’s actions or inactions); or (iii) any material breach by Pledgor (of any of its obligations under this Agreement that is not cured within ten (10) Business Days after Pledgor’s receipt of Secured Party’s written notice thereof except that if the obligation is disputed in good faith by Pledgor by notice to the Secured Party by the tenth Business Day after Pledgor’s receipt of such notice of breach, then, with respect to the portion of such obligation that is disputed in good faith, Pledgor shall be deemed in default only if it fails to perform within ten (10) Business Days after being ordered to do so by an arbitration ruling or a court of competent jurisdiction pursuant to a judgment, order or decree that becomes final and non-appealable or after such dispute is otherwise resolved by the parties.

(c) “ Follow-On Collateral ” means assets (net of liabilities) having a fair market value measured as of the last day of the Lock-Up Period of not less than the sum of $20 million plus an amount reasonably sufficient to cover any indemnity claims asserted in good faith in accordance with Section 7.3 or Article VIII of the Merger Agreement against any of the Advisor Companies (as defined in the Merger Agreement) before the end of the Follow-On Period, to the extent those claims remain unresolved or unpaid; the amount reasonably sufficient to cover such indemnity claims shall be equal to Secured Party’s good faith estimate of such amount as specified in a notice executed by Secured Party and delivered to Pledgor prior to the end of the Follow-On Period.

(d) “ REIT Change in Control ” means any of the following: (i) the consummation of a merger or consolidation of REIT with or into another entity or any other corporate reorganization, if more than fifty percent (50%) of the combined voting power of the continuing or surviving entity’s securities outstanding immediately after such merger, consolidation or reorganization is owned by Persons who were not shareholders of REIT immediately prior to such merger, consolidation or reorganization; (ii) the sale, transfer or other disposition of all or substantially all of REIT’s assets; (iii) the dissolution, liquidation or winding up of REIT; or (iv) any transaction as a result of which any Person is the “beneficial owner” (as defined in Rule 13d-3 under the Securities Exchange Act of 1934, as amended), directly or indirectly, of securities of REIT representing more than fifty percent (50%) of the total voting power represented by REIT’s then outstanding voting securities. A listing of the REIT Common Shares on a national securities exchange shall not constitute a “REIT Change of Control.”

(e) “ Remaining Collateral ” means assets having a fair market value measured as of the last day of the Follow-On Period of not less than an amount sufficient to cover any indemnity claims asserted in good faith in accordance with Section 7.3 or Article VIII against any of the Advisor Companies (assuming that the party asserting the claims prevails with respect to all such claims) before the end of the Follow-On Period to the extent those claims remain unresolved or unpaid; the amount reasonably sufficient to cover such indemnity claims shall be equal to Secured Party’s good faith estimate of such amount as specified in a notice executed by Secured Party and delivered to Custodian and Pledgor prior to the end of the Follow-On Period.

(a) As additional security for the payment and performance by Pledgor of all of the Secured Obligations and all of its obligations under this Agreement, Pledgor hereby pledges, assigns and grants to the Secured Party a first-priority security interest in all of its right, title and interest in and to the Collateral (the “ Pledge ”).

(b) Pledgor agrees to take such actions and to execute, deliver and file such instruments and documents, including, without limitation, one or more financing statements, as Secured Party may reasonably request to perfect Secured Party’s interest in the Collateral pursuant to this Agreement and to cause Secured Party to have a good, valid and perfected first pledge of, lien on and security interest in the Collateral, free and clear of any mortgage, pledge, lien, security interest, hypothecation, assignment, charge, right, encumbrance or restriction (individually, “ Encumbrance ,” and collectively, “ Encumbrances ”), but subject to restrictions on resale imposed

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pursuant to applicable federal and state securities laws or pursuant to Section 5.21 of the Merger Agreement (the “ Resale Restrictions ”). Without limiting the generality of the foregoing, to the extent that the Follow-On Collateral or the Remaining Collateral includes any cash or cash equivalents, then Pledgor agrees to execute and deliver a control account agreement with respect to such cash or cash equivalents and to comply with the terms thereof. At any time following an Event of Default, any or all of the Pledged Shares or other securities included in the Collateral may, at the option of Secured Party exercised in accordance with Sections 3(b) and 5(c), be registered in the name of Secured Party or in the name of its nominee.

(c) Pledgor shall deliver to Custodian all certificates representing the Pledged Shares which do not constitute the Escrow Shares to be held in custody in an account with the Custodian pursuant to the Custody Agreement (the “ Custodial Fund ”) simultaneously with the execution of this Agreement and, if at any time the Collateral consists of additional securities, then Pledgor shall deliver to Escrow Agent, all certificates or other documents evidencing such securities relating to such Collateral within five (5) Business Days after Pledgor’s acquisition thereof. Furthermore, Pledgor shall deliver to the Custodial Fund all certificates or other documents representing or evidencing the Escrow Shares which are released during the Lock-Up Period by the Escrow Agent to Pledgor pursuant to the terms of the Escrow Agreement to the Custodian to be held in the Custodial Fund. All certificates delivered to Custodian pursuant to this Agreement shall be registered in the name of Pledgor (except as provided in Section 2(b)), duly endorsed in blank or accompanied by instruments of transfer, duly executed by Pledgor, undated and in blank, together with any documentary tax stamps and any other necessary documents.

(a) So long as no Event of Default shall have occurred and be continuing:

(i) Pledgor shall be entitled to exercise any and all voting and/or consensual rights and powers relating or pertaining to the Collateral, subject to the terms hereof.

(ii) Pledgor shall be entitled to receive and retain (A) all regular periodic cash dividends or distributions payable on the Collateral, including dividends or distributions of income and dividend or distributions constituting returns of capital and (B) an amount equal to the federal and state taxes owed on any other cash dividend constituting a return of capital; provided, however, that all other dividends or distributions (including, without limitation, dividends payable in limited partnership interests), distributions in property and other distributions made on or in respect of the Collateral, whether resulting from a subdivision, combination or reclassification of the outstanding capital stock of REIT or stock dividend, and any and all cash and other property received in exchange for or redemption of any of the Collateral, shall be retained by Secured Party, or, if delivered to Pledgor, shall be held in trust for the benefit of Secured Party and forthwith delivered to Custodian within five (5) Business Days of the acquisition thereof and shall be considered as part of the Collateral, and shall be included in the Custodial Fund, for all purposes of this Agreement.

(iii) Secured Party shall execute and deliver (or cause to be executed and delivered) to Pledgor all such proxies, powers of attorney, dividend or distribution orders, and other instruments as Pledgor may reasonably request for the purpose of enabling Pledgor to exercise its voting and/or consensual rights and powers which Pledgor is entitled to exercise pursuant to Section 3(a)(i) and/or to receive the dividends or distributions which Pledgor is authorized to receive and retain pursuant to Section 3(a)(ii), and Pledgor shall execute and deliver (or cause to be executed and delivered) to Secured Party such instruments as may be reasonably required or may be reasonably requested by Secured Party to enable Secured Party to receive and retain the dividends or distributions, distributions in property, returns of capital and other distributions it is authorized to receive and retain pursuant to Section 3(a)(ii).

(b) Upon the occurrence and during the continuance of an Event of Default, all rights of Pledgor to exercise the voting and/or consensual rights and powers which Pledgor is entitled to exercise pursuant to Section 3(a)(i) and/or to receive the dividends or distributions which Pledgor is authorized to receive and retain pursuant to Section 3(a)(ii) shall cease, at the option of Secured Party, on not less than ten (10) days’ written notice to Pledgor, and all such rights shall thereupon become vested in Secured Party, who shall have the sole and exclusive right and authority to exercise such voting and/or consensual rights and powers and/or to receive and retain such dividends or distributions. In such case, Pledgor shall execute and deliver such documents as Secured

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Party may request to enable Secured Party to exercise such rights and receive such dividends or distributions. In addition, Secured Party is hereby appointed the attorney-in-fact of Pledgor, with full power of substitution, which appointment as attorney-in-fact is irrevocable and coupled with an interest, to take all such actions after the occurrence and during the continuance of an Event of Default, whether in the name of Secured Party or Pledgor, as Secured Party may consider necessary or desirable for the purpose of exercising such rights and receiving such dividends or distributions. Any and all money and other property paid over to or received by Secured Party pursuant to the provisions of this Section 3(b) shall be retained by Secured Party as part of the Collateral and shall be applied in accordance with the provisions hereof.

Pledgor may at any time propose that Secured Party accept substitute collateral in lieu of any of Pledgor’s portion of the Follow-On Collateral or Remaining Collateral as may be specified in writing by Pledgor. If, in the sole judgment of Secured Party, such proposed substitute collateral (hereinafter referred to as “ Replacement Assurance ”) is satisfactory in form and substance to Secured Party and affords Secured Party protection at least equivalent to the protection afforded by Pledgor’s portion of such Follow-On Collateral or Remaining Collateral, then Pledgor and Secured Party shall cooperate, at Pledgor’s sole cost and expense, to effect the substitution of such Replacement Assurances for Pledgor’s portion of the Follow-On Collateral or Remaining Collateral, including (i) the preparation, execution, delivery and filing of such agreements and other documents as may be requested by Secured Party in order to create and perfect in favor of Secured Party a perfected first-priority security interest in the Replacement Assurance, and (ii) execution and delivery of such documents as may be necessary to release Secured Party’s security interest in such Follow-On Collateral or Remaining Collateral. This Section 4 shall only apply with respect to Follow-On Collateral and Remaining Collateral.

(a) If at any time an Event of Default shall have occurred and be continuing, then, in addition to having the right to exercise any right or remedy of a secured party upon default under the Uniform Commercial Code as then in effect in any applicable jurisdiction and the right to exercise any right or remedy of Secured Party under the Merger Agreement or otherwise, Secured Party (or its nominee) shall, to the extent permitted by law, without being required to give any notice to Pledgor except as provided below:

(i) Apply any cash or cash equivalents held by Custodian or Secured Party hereunder in the manner provided in Section 5(f);

(ii) If there shall be no such cash or cash equivalents or if the cash or cash equivalents so applied shall be insufficient to pay in full the items specified in Sections 5(f)(i) and (ii), collect, receive, appropriate and realize upon the Collateral or any part thereof, and/or sell, assign, contract to sell or otherwise dispose of and deliver the Collateral or any part thereof, in its entirety or in portions, at public or private sale or at any broker’s board, on any securities exchange or at any of Secured Party places of business or elsewhere, for cash, upon credit or for future delivery, and at such price or prices as Secured Party may deem best, and Secured Party may (except as otherwise provided by law) be the purchaser of any or all of the Collateral so sold and thereafter may hold the same, absolutely, free from any right or