Exhibit 2.4 SECOND AMENDMENT TO CONTRIBUTION AGREEMENT THIS SECOND AMENDMENT TO CONTRIBUTION AGREEMENT ("Second Amendment") is made and executed as of this 28th day of September, 1998 by and between CORPORATE OFFICE PROPERTIES TRUST and CORPORATE OFFICE PROPERTIES, L.P. (collectively, the "Buyer") and the Sellers listed on the signature page to this Second Amendment and as defined in the Contribution Agreement (collectively, the "Sellers" and each individually, a "Seller"). A. Sellers and Buyer entered into a Contribution Agreement dated May 14, 1988, as amended on July 16, 1998 by a First Amendment to Contribution Agreement (the "Contribution Agreement"), pursuant to which Sellers agreed to contribute a property known as Brandon and certain interests in Entities which own certain real estate and a mortgage in Maryland to the Buyer in exchange for cash, the assumption of certain debt, and Common Shares and Convertible Preferred Shares. Capitalized terms used, but not defined, in this Second Amendment shall have the meanings given to such terms in the Contribution Agreement. B. Sellers and Buyer desire to amend the Contribution Agreement as set forth in this Second Amendment. NOW, THEREFORE, in consideration of the agreements contained herein and intending to be legally bound hereby, Sellers and Buyer agree as follows: 1. Exhibit "TIF Agreement" is hereby deleted from the Contribution Agreement, and Exhibit "TIF Agreement" attached hereto and made a part hereof, is hereby attached to and made part of the Contribution Agreement as Exhibit "TIF Agreement". 2. Buyer hereby elects to convert all of the Satisfied Indebtedness to Assumed Indebtedness pursuant to Section 1.83 of the Contribution Agreement. Sellers and CREG shall be released from all future liability under such converted Assumed Indebtedness. 3. Pursuant to Section 11.1.4 of the Contribution Agreement, Sellers have elected to transfer certain partnership and limited liability company interests prior to Closing as shown in Exhibit "Interest Changes" attached hereto and made a part hereof. Except as shown on Exhibit "Interest Changes", there have been no changes in the composition of any Entity between May 14, 1998 and the date hereof. Sellers represent and warrant that certified copies of all documents necessary to effectuate the transfers shown on Exhibit "Interest Changes" will be delivered to Buyer on or before the First Closing. 4. The term "Development Management Agreement" is hereby deleted from Section 1.31 of the Contribution Agreement, and the term "Project Consulting and Management Agreement" is substituted in its place. The term "Development Management Agreement" is hereby deleted wherever it appears in Section 5.7 of the Contribution Agreement, and the term "Project Consulting and Management Agreement" is hereby substituted in its place. Exhibit "Development Management Agreement" is hereby deleted from the Contribution Agreement, and Exhibit "Projects Consulting and Management Agreement" attached hereto and made a part hereof, is hereby attached to and made part of the Contribution Agreement as Exhibit "Project Management and Consulting Agreement". 5. The first sentence of Section 6.2.1 of the Contribution Agreement is amended by changing "December 31, 1998" to "March 31, 1999". The second sentence of Section 6.2.2 is revised by adding at the end thereof the following language: "; provided, however, that notwithstanding the foregoing, Buyer and Sellers shall consummate the Woodlands Closing simultaneously with the closing of the first financing transaction by Buyer for all or any portion of the Projects transferred to Buyer at the First Closing. In the event of such a simultaneous closing of a financing transaction with the Woodlands Closing, the Woodlands Gross Value shall be $17,600,000, and shall not be reduced pursuant to Section 3.2.5; and Sellers shall, from time to time, reimburse Buyer, within seven (7) days after presentation of a bill therefor, for all interest payments with respect to financing on the Woodlands I Project from the date of the Woodlands Closing until October 21, 1998." 6. Exhibit "Option Projects" to the Contribution Agreement is hereby deleted from the Contribution Agreement, and Exhibit "Option Projects" attached hereto and made a part hereof, is hereby attached to and made part of the Contribution Agreement as Exhibit "Option Projects". All references in the Contribution Agreement to the Option Project identified as "Annapolis Exchange" are deleted. 7. Exhibit "Projects" to the Contribution Agreement is hereby amended by adding to the reference for One Constellation Centre the following: "Unit 5, Constellation Centre Condominium vacant land 30,495 sq. ft. tract" and by changing the reference to Constellation Centre - Nations Bank Parcel from "25,933 sq. ft. tract" to "47,701 sq. ft. tract". 8. The address for notices to Buyer is hereby changed as follows: Corporate Office Properties Trust 401 City Avenue, Suite 615 Bala Cynwyd, PA 19004-1126 Attention: Clay W. Hamlin, III President and Chief Executive Officer 2 Copies of notices to Buyer shall still be sent as set forth in the Contribution Agreement. IN WITNESS WHEREOF, and intending to be legally bound hereby, Sellers and Buyer have executed this Second Amendment on the day and year first above written. BUYER: CORPORATE OFFICE PROPERTIES, L.P. By: Corporate Office Properties Trust, its sole general partner By: ----------------------------------- Clay W. Hamlin, III President and Chief Executive Officer SELLERS: CONSTELLATION PROPERTIES, INC., a Maryland corporation By: ----------------------------------- Dan R. Skowronski Secretary CPI NATIONAL BUSINESS PARK I, INC., a Maryland corporation By: ----------------------------------- Dan R. Skowronski Secretary CPI NATIONAL BUSINESS PARK II, INC., a Maryland corporation By: ----------------------------------- Dan R. Skowronski Secretary 3 [SIGNATURES CONTINUED ON NEXT PAGE] CPI NATIONAL BUSINESS PARK IV, INC., a Maryland corporation By: ----------------------------------- Dan R. Skowronski Secretary CPO CONSTELLATION CENTRE, INC., a Maryland corporation By: ----------------------------------- Dan R. Skowronski Secretary CPO LAUREL TOWER, INC., a Maryland corporation By: ----------------------------------- Dan R. Skowronski Secretary CPO THREE CENTRE PARK, INC., a Maryland corporation By: ----------------------------------- Dan R. Skowronski Secretary CPI BROWN'S WHARF, INC., a Maryland corporation By: ----------------------------------- Dan R. Skowronski Secretary 4 [SIGNATURES CONTINUED ON NEXT PAGE] CPI PARTNER, INC., a Maryland corporation By: ----------------------------------- Dan R. Skowronski Secretary CPI TRED AVON, INC., a Maryland corporation By: ----------------------------------- Dan R. Skowronski Secretary CPI GATESPRING, INC., a Maryland corporation By: ----------------------------------- Dan R. Skowronski Secretary 5 EXHIBIT "TIF AGREEMENT " INDEMNIFICATION AGREEMENT (National Business Park--TIF) THIS INDEMNIFICATION AGREEMENT ("Agreement") is made this day of September, 1998 by CONSTELLATION PROPERTIES, INC. ("CPI") in favor of CORPORATE OFFICE PROPERTIES L.P. ("COPLP"); CPI being sometimes referred to as "Indemnitor" and COPLP, and its successors and assigns, being sometimes referred to as "Indemnitee." WITNESSETH WHEREAS, CPI, through various related and affiliated entities, has developed and continues to develop the "National Business Park", which is located in Annapolis Junction, Anne Arundel County, Maryland (the "Park"); WHEREAS, in connection with the development of the Park, CPI determined, in conjunction with the County Council of Anne Arundel County, Maryland, that in order to most efficiently and effectively develop the necessary infrastructure and public improvements in and around the vicinity of the Park, that Anne Arundel County would (i) impose tax incremental financing on certain properties located in the County, including, among others, the Park, and (ii) create a Special Tax District which included the Park pursuant to the authority granted to the County Council by Article 6, Title 4A, Section 4A-101 et seq. of the Anne Arundel County Code; WHEREAS, the Special Tax District pertaining to the Park is commonly referred to as the "NBP Special Tax District" and was approved by the County Council of Anne Arundel County on March 4, 1998, in Bill No. 15-98; WHEREAS, as of the date hereof, COPLP has (i) acquired an ownership interest in several of the NBP Properties described as Lot 3B (commonly referred to as the "Tower" or "One National Business Park"), Lot 6AR (known as "131 National Business Park"), Lot 6-BR (known as "133 National Business Park"), Lot 7A (known as "135 National Business Park") and Lot 7B (known as "141 National Business Park") and (ii) will acquire an interest in Lot 11 (known as "134 National Business Park") pursuant to the terms of that certain Option Agreement dated May 14, 1998 by and between NBP-III, LLC and COPLP; WHEREAS, One National Business Park, 131 National Business Park, 133 National Business Park, 135 National Business Park and 141 National Business Park and 134 National Business Park are referred to collectively herein as the "COPLP Properties"; WHEREAS, CPI does not anticipate that there will be any increase in the taxes or assessments levied on the COPLP Properties as a result of the tax incremental financing or the creation of the NBP Tax District, as compared to the taxes or assessments that would be levied on the COPLP Properties if the tax incremental financing or the NBP Tax District did not exist; WHEREAS, in consideration of COPLP acquiring an ownership interest in the COPLP Properties, to the extent that the taxes and/or assessments levied on the COPLP Properties as a result of the creation and continued existence of the tax incremental financing and/or the NBP Tax District exceed those taxes and/or assessments which would be levied if the tax incremental financing and/or NBP Tax District did not exist (the "Tax Differential"), CPI has agreed to indemnify and hold COPLP harmless from and against any additional taxes and/or assessments resulting from the Tax Differential which are levied on the COPLP Properties in which COPLP or any affiliates or subsidiary acquires an ownership interest. NOW THEREFORE, it is mutually agreed, as follows: 1. Incorporation of Recitals. The Recitals shall be deemed to be an integral part of this Agreement. 2. Indemnification. 2.1 Indemnitor hereby indemnifies Indemnitee and undertakes to hold it harmless from the Tax Differential and shall reimburse Indemnitee within forty-five (45) days after receipt from Indemnitee of a written notice identifying the amount of the Tax Differential and reasonable supporting documentation ("Indemnitee's Request"). 2.2 Indemnitor shall notify Indemnitee in writing within thirty (30) days after receipt of Indemnitee's Request of any objections to the Indemnitee's Request (the "Objection Notice"). If Indemnitor delivers an Objection Notice within the thirty (30) day period, Indemnitor shall have the right to extend the forty-five (45) day period for payment for an additional period of forty-five (45) days (resulting in payment being required within ninety (90) days after the date of Indemnitee's Request) to permit the Indemnitor to evaluate the cause for the Tax Differential with the appropriate officials of Anne Arundel County. 2 2.3 If Indemnitor determines, in conjunction with Anne Arundel County, that the Tax Differential claimed by the Indemnitor was not computed accurately, Indemnitor shall notify the Indemnitee in writing on or before that day which is sixty (60) days after the date of Indemnitee's Request of the accurate amount of the Tax Differential, if any, together with reasonable supporting documentation which is either prepared by Anne Arundel County or obtained from its records. 2.4 Any claims made by Indemnitee under the terms of this Agreement shall be made within three (3) years after the date of that the Tax Differential is assessed or levied. 3. Term. The term of this Agreement shall be from the date hereof to that date which is twenty (20) calendar years after the date hereof ("Term"). Indemnitee shall have no further rights to deliver an Indemnitee's Request after the expiration of the Term. 4. Binding Nature. This Agreement and all duties and rights hereunder shall run with the land and shall be binding on Indemnitor's successors and assigns and shall inure to the benefit of Indemnitee's successors and assigns. 5. Miscellaneous. (a) Notices. Any notice required by the terms hereof shall be given in writing at the address set forth below by any of the following means: (a) personal service, (b) electronic communication, whether by facsimile, telex, telegram or telecopy, (c) registered or certified United State mail, postage prepaid, return receipt requested, or (d) by nationally recognized overnight delivery service, as follows: CPI: Constellation Properties, Inc. 8815 Centre Park Drive, Suite 100 Columbia, Maryland 21045 Attn: President With a copy to: Constellation Properties, Inc. 250 West Pratt Street, 24th Floor Baltimore, Maryland 21201 Attn: General Counsel COPLP: Corporate Office Properties, L.P. 8815 Centre Park Drive, Suite 400 Columbia, Maryland 21045 Attn: General Counsel 3 With a copy to: Corporate Office Properties L.P. Corporate Office Properties Trust 401 City Avenue, Suite 615 Bala Cynwyd, PA 19004-1126 Attention: Clay W. Hamlin, III President and Chief Executive Officer Such address(es) may be changed by either party by notice to the other in the manner provided above. Any notice sent (i) pursuant to subsection (a) shall be deemed received upon personal service, (ii) pursuant to subsection (b) shall be deemed received upon dispatch by electronic means, (iii) pursuant to subsection (c) shall be deemed received three (3) days following deposit in the United States mail, and (iv) pursuant to subsection (d) shall be deemed received one (1) business day after delivery to the nationally recognized overnight delivery service. (b) Applicable Law. The formation of this Agreement and the respective rights and obligations of the parties under this Agreement shall be construed in accordance with the laws of the State of Maryland. (c) Captions. The captions of the Agreement are for convenience purposes only and shall have no effect on its construction or interpretation. (d) Counterparts. This Agreement may be executed simultaneously in one or more counterparts, each of which shall be deemed an original but all of which together shall constitute one and the same instrument. (e) Entire Agreement.This Agreement, together with any exhibits attached hereto, represents the entire agreement between Owner and Manager and all prior agreements and negotiations have been merged herein. This Agreement may not be changed or terminated orally. (f) Severability. Each provision of this Agreement is intended to be severable. If any term or provision of this Agreement shall be determined by a court of competent jurisdiction to be illegal or invalid for any reason whatsoever, that provision shall be severed from this Agreement and shall not affect the validity of the remainder of this Agreement. (g) Attorney's Fees. If any action at law or in equity is necessary to enforce or interpret the terms of this Agreement, the prevailing party shall be entitled to reasonable attorney's fees, costs and necessary disbursements in addition to any other relief to which such may be entitled. 4 IN WITNESS WHEREOF, the parties have executed this Agreement to be effective on the day and year first set forth above. ATTEST: CONSTELLATION PROPERTIES, INC. By: - ------------------------------- ------------------------------------- Dan R. Skowronski, Secretary ATTEST: CORPORATE OFFICE PROPERTIES L.P. By: Corporate Office Properties Trust, its sole general partner By: - ------------------------------- ------------------------------------- Clay W. Hamlin, III President and Chief Executive Officer 5 STATE OF COUNTY OF ,TO WIT: ------------ ------------------- I HEREBY CERTIFY, that on this day of , 1998, before --- ----------- me, undersigned Notary Public of said State, personally appeared , who acknowledged himself to be the - --------------------------- --------------- of Constellation Properties, Inc., a Maryland corporation, known to me or satisfactorily proven to be the person whose name is subscribed to the within instrument, and acknowledged that he executed the same for the purposes therein contained as the duly authorized of said corporation ---------------- by signing the name of the corporation himself as . ------------------------ IN WITNESS WHEREOF, I have set my hand and Notarial Seal, the day and year first above written. ------------------------------------ Notary Public My commission expires: STATE OF COUNTY OF ,TO WIT: ------------ ------------------- I HEREBY CERTIFY, that on this day of , 1998, ---- ------------ before me, undersigned Notary Public of said State, personally appeared CLAY W. HAMLIN, III, known to me or satisfactorily proven to be the person whose name is subscribed to the within instrument, who acknowledged himself to be the President and Chief Executive Officer of Corporate Office Proerties Trust, general partner of Corporate Office Properties L.P., a limited partnership and acknowledged that he executed the same for the purposes therein contained as the duly authorized President and Chief Executive Officer of said general partner of said limited partnership by signing the name of the corporation by himself as President and Chief Executive Officer. IN WITNESS WHEREOF, I have set my hand and Notarial Seal, the day and year first above written. ----------------------------------- Notary Public My commission expires: ------------- 6 ATTORNEY CERTIFICATION THE UNDERSIGNED, an attorney admitted to practice before the Court of Appeals of Maryland, hereby certifies that the above instrument was prepared by me or under my supervision. ----------------------------------- John Harris Gurley, Attorney-at-Law 7 EXHIBIT "INTEREST CHANGES"