Exhibit 99.1

Supplemental Information

(Unaudited)

September 30, 2008

Corporate Office Properties Trust

Index to Supplemental Information (Unaudited)

September 30, 2008

	Page
Highlights and Discussion
Reporting Period Highlights – Quarter Ended September 30, 2008	1
Forward-Looking Statements	3
Financial Statements
Quarterly Selected Financial Summary Data	4
Quarterly Consolidated Balance Sheets	5
Quarterly Consolidated Statements of Operations	6
Quarterly Consolidated Reconciliations of Funds From Operations (FFO), Adjusted Funds From Operations (AFFO) and Earnings per diluted share, as adjusted	7
Quarterly Consolidated Reconciliations of Earnings Before Interest, Income Taxes, Depreciation and Amortization (EBITDA), Combined Net Operating Income (NOI), Discontinued Operations and Gains on Sales of Real Estate	8
Selected Financial Analyses
Quarterly Equity Analysis	9
Quarterly Debt Analysis	10
Quarterly Operating Ratios	11
Quarterly Dividend Analysis	12
Investor Composition and Analyst Coverage	13
Debt Maturity Schedule – September 30, 2008	14
Portfolio Summary
Property Summary by Region – September 30, 2008 – Wholly Owned Properties	15
Property Summary by Region – September 30, 2008 – Joint Venture Properties	21
Property Occupancy Rates by Region by Quarter – Wholly Owned Properties	22
Property Occupancy Rates by Region by Quarter – Joint Venture Properties	23
Top Twenty Office Tenants of Wholly Owned Properties as of September 30, 2008	24
Combined Real Estate Revenue and Combined Net Operating Income by Geographic Region by Quarter	25
Same Office Property Cash and GAAP Net Operating Income by Quarter	26
Average Occupancy Rates by Region for Same Office Properties	27
Office Lease Expiration Analysis by Year for Wholly Owned Properties	28
Quarterly and Year to Date Office Renewal Analysis for Wholly Owned Properties as of September 30, 2008	29
Year to Date Wholly Owned Acquisition and Disposition Summaries as of September 30, 2008	30
Development Summary as of September 30, 2008	31
Total Development Placed into Service as of September 30, 2008	33
Land Inventory as of September 30, 2008	34
Joint Venture Summary as of September 30, 2008	35
Reconciliations of Non GAAP Measurements	36

To Members of the Investment Community:

We prepared this supplemental information package to provide you with additional detail on our properties and operations. The information in this package is unaudited, furnished to the Securities and Exchange Commission (“SEC”) and should be read in conjunction with our quarterly and annual reports. If you have any questions or comments, please contact Ms. Mary Ellen Fowler, Vice President and Treasurer at (443) 285-5450 or maryellen.fowler@copt.com. Reconciliations between GAAP and non GAAP measurements have been provided on page 36. Refer to our Form 8-K for definitions of certain terms used herein.

Corporate Office Properties Trust (COPT) (NYSE: OFC) is a specialty office real estate investment trust (REIT) that focuses on strategic customer relationships and specialized tenant requirements in the U.S. Government, Defense Information Technology and Data sectors. The Company acquires, develops, manages and leases properties which are typically concentrated in large office parks primarily located adjacent to government demand drivers and/or in growth corridors. More information on COPT can be found at www.copt.com.

Reporting Period Highlights – Quarter Ended September 30, 2008

Financial Results

·Reported FFO – diluted of $36.2 million, or $0.64 per share/unit, for the quarter ended September 30, 2008 as compared to $32.4 million, or $0.58 per share/unit, for the comparable 2007 period, representing an increase of 10.3% per share/unit.

·Reported net income available to common shareholders of $8.9 million, or $0.19 per diluted share, for the quarter ended September 30, 2008 as compared to $7.4 million, or $0.15 per diluted share, for the comparable 2007 period.

·Reported AFFO – diluted of $25.8 million for the quarter ended September 30, 2008 as compared to $23.9 million for the comparable 2007 period, representing an increase of 8.0%.

·Our diluted FFO payout ratio was 61.4% for the quarter ended September 30, 2008 as compared to 58.3% for the comparable 2007 period. Our diluted AFFO payout ratio was 86.1% for the quarter ended September 30, 2008 as compared to 79.1% for the comparable 2007 period.

Acquisitions / Dispositions

·On July 16, 2008, we acquired, for $8.1 million, a 31-acre land parcel in San Antonio, Texas which we believe can support approximately 500,000 developable square feet.

·On August 28, 2008, we acquired, for $8.0 million, a 107-acre land parcel in Frederick, Maryland which we believe can support approximately 1.0 million developable square feet.

Development Activities

·During the quarter ended September 30, 2008, we placed into service 43,721 square feet of the 53,745 square foot property located at 9925 Federal Drive (Hybrid II) in Colorado Springs, Colorado.

·During the quarter ended September 30, 2008, we completed leases on an aggregate of 121,571 square feet in the following newly-constructed properties:

·38,900 of the 155,731 square foot property located at 302 Sentinel Drive (302 NBP) in Annapolis Junction, Maryland to a large credit-worthy tenant;

·33,809 of the 145,723 square foot property located at 10807 New Allegiance Drive (Epic One) in Colorado Springs, Colorado to Lockheed Martin Corporation;

·27,862 of the 105,964 square foot property located at 5520 Research Park Drive (UMBC) in Baltimore, Maryland to RMF Engineering, Inc.; and

·an aggregate of 21,000 square feet under two leases at 5825 University Research Court (M Square Research Park) in College Park, Maryland.

1

Operations

·Our wholly owned portfolio was 93.2% occupied and 94.3% leased as of September 30, 2008. Our entire portfolio was 93.1% occupied and 94.2% leased as of September 30, 2008.

·During the quarter ended September 30, 2008, we completed leases for 333,000 square feet on the Unisys Campus in Blue Bell, Pennsylvania, which included the following:

·a new lease with Merck, Inc. to continue occupancy of the entire 219,000 square foot property located at 785 Jolly Road; and

·a renewal of Unisys Corporation for the entire 114,000 square foot property located at 751 Jolly Road.

·Our same office property cash NOI, excluding the effect of a $431,000 reduction in lease termination fees, increased for the quarter ended September 30, 2008 by $1.8 million, or 3.1%, as compared to the quarter ended September 30, 2007. Including the effect of lower lease termination fees, our same office property cash NOI increased $1.4 million, or 2.4%, as compared to the quarter ended September 30, 2007. Our same office portfolio consists of 218 properties and represents 89.9% of the rentable square footage of our consolidated properties as of September 30, 2008.

·The weighted average lease term of our wholly owned portfolio was 4.8 years as of September 30, 2008, with an average contractual rental rate (including tenant reimbursements of operating costs) of $22.17 per square foot.

·For the quarter ended September 30, 2008, we renewed 850,000 square feet, or 79.6%, of our expiring office leases (based upon square footage), with an average committed cost of $8.24 per square foot. For our renewed space during the quarter ended September 30, 2008, we realized increases of 26.7% in total rent, as measured from the GAAP straight-line rent in effect preceding the renewal date, and 13.1% in total cash rent. For our renewed and retenanted space of 950,000 square feet during the quarter ended September 30, 2008, we realized increases of 23.1% in total rent, as measured from the GAAP straight-line rent in effect preceding the renewal date, and 9.8% in total cash rent. The average committed cost for our space renewed and retenanted during the quarter ended September 30, 2008 totaled $10.14 per square foot. For the nine months ended September 30, 2008, we renewed 1.6 million square feet, or 77.9%, of our expiring office leases (based upon square footage), with an average committed cost of $6.49 per square foot.

·We recognized $188,000 in lease termination fees, net of write-offs of related straight-line rents and accretion of intangible assets and liabilities (i.e., SFAS 141 revenues), in the quarter ended September 30, 2008, as compared to $1.2 million in the quarter ended September 30, 2007.

Financing Activity and Capital Transactions

·As of September 30, 2008, our ratio of debt to market capitalization was 41.4%, and our ratio of debt to undepreciated book value of real estate assets was 58.3%. We achieved an EBITDA to interest coverage ratio of 3.04x and an EBITDA to fixed charge coverage ratio of 2.53x for the quarter ended September 30, 2008.

·On July 18, 2008, we borrowed $221.4 million under a mortgage loan requiring interest only payments for the term at a variable rate of LIBOR plus 225 basis points. This loan facility has a four-year term with an option to extend by an additional year. We used $63.5 million of the proceeds from this loan to repay construction loan facilities that were due to mature in 2008, $11.8 million to repay borrowings under an additional construction loan facility, $142.0 million to repay borrowings under our unsecured revolving credit facility and the balance to fund transaction costs.

·The aggregate amount of debt repaid by us totaled $187.6 million in the quarter ended September 30, 2008 and $241.1 million in the nine months ended September 30, 2008, excluding scheduled principal amortization payments and repayments of our unsecured revolving credit facility and revolving construction facility. We have no remaining debt scheduled to mature during the balance of 2008 other than scheduled principal amortization.

·In September 2008, we issued 3.7 million common shares at a public offering price of $39.00 per share for net proceeds of $139.2 million  after underwriting discounts but before offering expenses. The net proceeds were used to pay down our Revolving Credit Facility.

·Our Board of Trustees increased our dividend per Common Share of beneficial interest for the third quarter of 2008 to $0.3725 per share, representing a 9.6% increase from the previous per share quarterly dividend of $0.34.

2

Other Transaction

·On August 26, 2008, we loaned $24.8 million to the owner of a 17-story Class A+ office property containing 470,603 square feet in Baltimore, Maryland. We have a secured interest in the ownership of the entity that owns the property and adjacent land parcels that is subordinate to that of a first mortgage on the property. The loan carries an interest rate of 16.0% and matures on August 26, 2011. The property was 91% leased as of August 26, 2008.

Subsequent Events

·On October 1, 2008, we placed into service 90,607 square feet in two properties located at 7700 Potranco Road in San Antonio, Texas.  These two buildings are leased 100% to a large credit-worthy tenant.

·On October 24, 2008, we executed a swap for an aggregate notional amount of $100.0 million at a fixed one-month LIBOR rate of 2.51%, which commences on November 3, 2008 and expires on December 31, 2009.

Forward-Looking Statements

This supplemental information contains “forward-looking” statements, as defined in Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934 that are based on our current expectations, estimates and projections about future events and financial trends affecting us.  Forward-looking statements can be identified by the use of words such as “may,” “will,” “should,” “expect,” “estimate” or other comparable terminology.  Forward-looking statements are inherently subject to risks and uncertainties, many of which we cannot predict with accuracy and some of which we might not even anticipate.  Accordingly, we can give no assurance that these expectations, estimates and projections will be achieved.  Future events and actual results may differ materially from those discussed in the forward-looking statements.

Important factors that may affect these expectations, estimates, and projections include, but are not limited to:

·our ability to borrow on favorable terms;

·general economic and business conditions, which will, among other things, affect office property demand and rents, tenant creditworthiness, interest rates and financing availability;

·adverse changes in the real estate markets including, among other things, increased competition with other companies;

·risk of real estate acquisition and development, including, among other things, risks that development projects may not be completed on schedule, that tenants may not take occupancy or pay rent or that development or operating costs may be greater than anticipated;

·risks of investing through joint venture structures, including risks that our joint venture partners may not fulfill their financial obligations as investors or may take actions that are inconsistent with our objectives;

·our ability to satisfy and operate effectively under federal income tax rules relating to real estate investment trusts and partnerships;

·governmental actions and initiatives; and

·environmental requirements.

We undertake no obligation to update or supplement any forward-looking statements.  For further information, please refer to our filings with the Securities and Exchange Commission, particularly the section entitled “Risk Factors” in Item 1 of our Annual Report on Form 10-K for the year ended December 31, 2007.

3

Quarterly Selected Financial Summary Data

(Dollars in thousands)

	2008									2007
	September 30			June 30			March 31			December 31			September 30
Revenues from real estate operations	$	101,644		$	98,111		$	97,151		$	94,567		$	94,102
Total revenues	$	191,646		$	120,535		$	107,765		$	103,065		$	105,059
Combined net operating income	$	65,781		$	64,228		$	62,692		$	63,734		$	62,573
EBITDA	$	62,372		$	60,327		$	60,150		$	61,255		$	61,783
Net income	$	12,949		$	12,853		$	11,395		$	9,929		$	11,431
Preferred share dividends	(4,025		)	(4,026		)	(4,025		)	(4,025		)	(4,025		)
Net income availableto common shareholders	$	8,924		$	8,827		$	7,370		$	5,904		$	7,406
Earnings per diluted share	$	0.19		$	0.18		$	0.15		$	0.12		$	0.15
Funds from operations (FFO) - diluted	$	36,187		$	34,205		$	32,373		$	32,832		$	32,352
FFO per diluted share	$	0.64		$	0.61		$	0.58		$	0.59		$	0.58
Adjusted FFO - diluted	$	25,774		$	25,148		$	24,490		$	23,232		$	23,856
Payout ratios:
Earnings payout	215.0		%	183.5		%	219.4		%	272.6		%	217.3		%
FFO - diluted	61.4		%	55.5		%	58.5		%	57.5		%	58.3		%
AFFO - diluted	86.1		%	75.4		%	77.4		%	81.2		%	79.1		%
Total dividends/distributions	$	26,394		$	23,160		$	23,134		$	23,064		$	23,059

Note: The above presentation does not separately report discontinued operations.

4

Quarterly Consolidated Balance Sheets

(Dollars in thousands except per share data)

	2008									2007
	September 30			June 30			March 31			December 31			September 30
Assets
Investment in real estate:
Land - operational	$	421,311		$	420,182		$	416,632		$	416,711		$	415,061
Land - development	221,066			208,742			210,449			214,696			218,890
Construction in progress	281,098			247,422			198,514			181,316			193,081
Buildings and improvements	2,159,530			2,145,700			2,095,178			2,079,963			2,029,300
Less: accumulated depreciation	(339,429		)	(320,879		)	(303,709		)	(288,747		)	(270,899		)
Net investment in real estate	2,743,576			2,701,167			2,617,064			2,603,939			2,585,433
Cash and cash equivalents	21,316			12,857			37,607			24,638			21,895
Restricted cash	15,534			23,066			16,712			15,121			16,874
Accounts receivable, net	13,044			23,452			19,832			24,831			20,680
Deferred rent receivable	62,137			59,238			56,330			53,631			50,891
Intangible assets on real estate acquisitions, net	98,282			104,136			102,647			108,661			116,368
Deferred charges, net	51,680			48,620			48,231			49,051			46,019
Prepaid and other assets	94,159			37,934			38,321			51,981			57,863
Total assets	$	3,099,728		$	3,010,470		$	2,936,744		$	2,931,853		$	2,916,023
Liabilities and shareholders’ equity
Liabilities:
Mortgage and other loans payable	$	1,656,280		$	1,704,351		$	1,645,968		$	1,625,842		$	1,599,912
3.5% Exchangeable Senior Notes	200,000			200,000			200,000			200,000			200,000
Accounts payable and accrued expenses	93,676			82,526			66,210			75,535			80,281
Rents received in advance and security deposits	26,372			32,569			33,169			31,234			25,568
Dividends and distributions payable	25,774			22,548			22,519			22,441			22,433
Deferred revenue associated with acquired operating leases	11,832			12,762			10,665			11,530			12,475
Distributions in excess of investment in unconsolidated real estate joint ventures	4,668			4,506			4,215			4,246			4,124
Other liabilities	7,059			8,820			10,171			8,288			6,855
Total liabilities	2,025,661			2,068,082			1,992,917			1,979,116			1,951,648
Minority interests:
Common units in the Operating Partnership	122,557			111,033			111,904			114,127			115,837
Preferred units in the Operating Partnership	8,800			8,800			8,800			8,800			8,800
Other consolidated real estate joint ventures	10,169			10,259			8,421			7,168			6,970
Total minority interests	141,526			130,092			129,125			130,095			131,607
Commitments and contingencies	—			—			—			—			—
Shareholders’ equity:
Preferred Shares ($0.01 par value; 15,000,000 authorized)	81			81			81			81			81
Common Shares of beneficial interest ($0.01 par value; 75,000,000 authorized, 51,530,162 shares issued as of September 30, 2008)	515			477			476			474			473
Additional paid-in capital	1,086,210			956,683			953,473			950,615			949,392
Cumulative distributions in excess of net income	(152,589		)	(142,330		)	(134,960		)	(126,156		)	(115,963		)
Accumulated other comprehensive loss	(1,676		)	(2,615		)	(4,368		)	(2,372		)	(1,215		)
Total shareholders’ equity	932,541			812,296			814,702			822,642			832,768
Total shareholders’ equity and minority interests	1,074,067			942,388			943,827			952,737			964,375
Total liabilities and shareholders’ equity	$	3,099,728		$	3,010,470		$	2,936,744		$	2,931,853		$	2,916,023

Note: The above presentation does not separately report discontinued operations.

5

Quarterly Consolidated Statements of Operations

(Dollars and units in thousands)

	2008									2007
	September 30			June 30			March 31			December 31			September 30
Revenues
Rental revenue	$	85,060		$	83,154		$	81,710		$	81,046		$	80,038
Tenant recoveries and other real estate operations revenue	16,584			14,957			15,441			13,521			14,064
Construction contract revenues (1)	89,653			21,899			10,136			7,716			10,047
Other service operations revenues	349			525			478			782			910
Total revenues	191,646			120,535			107,765			103,065			105,059
Expenses
Property operating expenses	35,854			33,957			34,542			31,090			31,577
Depreciation and amortization associated with real estate operations	25,583			24,955			24,892			25,889			26,025
Construction contract expenses (1)	87,111			21,472			9,905			7,597			9,507
Other service operations expenses	546			454			602			733			806
General and administrative expenses	6,103			6,036			5,933			5,758			5,743
Total operating expenses	155,197			86,874			75,874			71,067			73,658
Operating income	36,449			33,661			31,891			31,998			31,401
Interest expense	(20,506		)	(19,437		)	(20,309		)	(20,719		)	(20,968		)
Amortization of deferred financing costs	(1,169		)	(910		)	(803		)	(970		)	(901		)
Gain on sales of non-real estate investments	1			5			46			—			—
Income from continuing operations before equity in loss of unconsolidated entities, income taxes and minority interests	14,775			13,319			10,825			10,309			9,532
Equity in loss of unconsolidated entities	(57		)	(56		)	(54		)	(27		)	(46		)
Income tax (expense) benefit	(97		)	107			(112		)	(89		)	(197		)
Income from continuing operations before minority interests	14,621			13,370			10,659			10,193			9,289
Minority interest in income from continuing operations
Common units in the Operating Partnership	(1,593		)	(1,378		)	(987		)	(916		)	(789		)
Preferred units in the Operating Partnership	(165		)	(165		)	(165		)	(165		)	(165		)
Other consolidated entities	90			(120		)	14			32			12
Income from continuing operations	12,953			11,707			9,521			9,144			8,347
(Loss) income from discontinued operations, net of minority interests	(8		)	1,115			1,072			424			2,046
Income before gain on sales of real estate	12,945			12,822			10,593			9,568			10,393
Gain on sales of real estate, net of income taxes and minority interests	4			31			802			361			1,038
Net income	12,949			12,853			11,395			9,929			11,431
Preferred share dividends	(4,025		)	(4,026		)	(4,025		)	(4,025		)	(4,025		)
Net income available to common shareholders	$	8,924		$	8,827		$	7,370		$	5,904		$	7,406
For EPS Computations:
Numerator for Dilutive EPS	$	8,924		$	8,827		$	7,370		$	5,904		$	7,406
Denominator:
Weighted average common shares - basic	47,273			47,110			47,001			46,947			46,781
Dilutive effect of share-based compensation awards	916			888			765			914			1,005
Weighted average common shares - diluted	48,189			47,998			47,766			47,861			47,786
Earnings per diluted share	$	0.19		$	0.18		$	0.15		$	0.12		$	0.15

(1) Reflects the effect of increases from amounts previously reported for construction contract revenues and expenses by equal dollar amounts (zero net effect) in the quarters ended June 30 and March 31, 2008 resulting from a change in our presentation of activity from a construction contract.

6

Quarterly Consolidated Reconciliations of Funds From Operations (FFO), Adjusted Funds From

Operations (AFFO) and Earnings per diluted share, as adjusted

(Dollars in thousands)

	2008									2007
	September 30			June 30			March 31			December 31			September 30
Net income	$	12,949		$	12,853		$	11,395		$	9,929		$	11,431
Combined real estate related depreciation and other amortization	25,583			24,955			24,944			26,607			26,266
Depreciation and amortization of unconsolidated real estate entities	162			163			164			163			166
Depreciation and amortization allocable to minority interests in other consol. entities	(74		)	(75		)	(49		)	(51		)	(48		)
Gain on sales of real estate properties, excluding development, net of income taxes	—			(1,250		)	(1,380		)	(1,049		)	(2,789		)
Funds from operations (FFO)	38,620			36,646			35,074			35,599			35,026
Minority interest - common units, gross	1,592			1,585			1,324			1,258			1,351
Preferred share dividends	(4,025		)	(4,026		)	(4,025		)	(4,025		)	(4,025		)
Funds from operations (FFO) - basic & diluted	36,187			34,205			32,373			32,832			32,352
Straight line rent adjustments	(2,850		)	(2,778		)	(2,656		)	(2,680		)	(3,247		)
Amortization of deferred market rental revenue	(555		)	(458		)	(445		)	(416		)	(585		)
Recurring capital expenditures	(7,008		)	(5,821		)	(4,782		)	(6,504		)	(4,664		)
Adjusted funds from operations (AFFO) - diluted	$	25,774		$	25,148		$	24,490		$	23,232		$	23,856
Preferred dividends	$	4,025		$	4,026		$	4,025		$	4,025		$	4,025
Preferred distributions	165			165			165			165			165
Common distributions	3,021			2,772			2,771			2,777			2,777
Common dividends	19,183			16,197			16,173			16,097			16,092
Total dividends/distributions	$	26,394		$	23,160		$	23,134		$	23,064		$	23,059
Denominator for earnings per share - diluted	48,189			47,998			47,766			47,861			47,786
Common units	8,130			8,151			8,154			8,167			8,297
Denominator for funds from operations per share - diluted	56,319			56,149			55,920			56,028			56,083

7

Quarterly Consolidated Reconciliations of Earnings Before Interest, Income Taxes, Depreciation and Amortization

(EBITDA), Combined Net Operating Income (NOI), Discontinued Operations and Gains on Sales of Real Estate

(Dollars in thousands)

	2008									2007
	September 30			June 30			March 31			December 31			September 30
Net income	$	12,949		$	12,853		$	11,395		$	9,929		$	11,431
Combined interest expense	20,506			19,447			20,350			20,799			21,145
Combined amortization of deferred financing costs	1,169			910			803			970			901
Combined income tax expense (benefit) (1)	97			(102		)	685			1,201			197
Depreciation of furniture, fixtures and equipment (FF&E)	401			392			384			358			339
Combined real estate related depreciation and other amortization	25,583			24,955			24,944			26,607			26,266
Minority interest - preferred units	165			165			165			165			165
Minority interest - other consolidated entities	(90		)	122			100			(32		)	(12		)
Minority interest - common units, gross	1,592			1,585			1,324			1,258			1,351
Earnings before interest, income taxes, depreciation and amortization (EBITDA)	$	62,372		$	60,327		$	60,150		$	61,255		$	61,783
Add back:
General and administrative	6,103			6,036			5,933			5,758			5,743
Depreciation of FF&E included in general and administrative expense	(401		)	(392		)	(384		)	(358		)	(339		)
Income from service operations	(2,345		)	(498		)	(107		)	(168		)	(644		)
Gain on sales of depreciated real estate properties	—			(1,250		)	(1,276		)	(1,093		)	(2,789		)
Gain on sale of non-real estate investments	(1		)	(5		)	(46		)	—			—
Non-operational property sales and real estate services	(4		)	(46		)	(1,632		)	(1,687		)	(1,227		)
Equity in loss of unconsolidated entities	57			56			54			27			46
Combined net operating income (NOI)	$	65,781		$	64,228		$	62,692		$	63,734		$	62,573
Discontinued Operations
Revenues from real estate operations	$	3		$	85		$	270		$	549		$	736
Property operating expenses	(12		)	(11		)	(187		)	(292		)	(688		)
Depreciation and amortization	—			—			(52		)	(718		)	(241		)
Income taxes	—			—			—			(44		)	—
Interest	—			(10		)	(41		)	(80		)	(177		)
Gain on sales of depreciated real estate properties	—			1,250			1,276			1,093			2,789
(Loss) income from discontinued operations	(9		)	1,314			1,266			508			2,419
Minority interests in discontinued operations	1			(199		)	(194		)	(84		)	(373		)
(Loss) income from discontinued operations, net of minority interests	$	(8	)	$	1,115		$	1,072		$	424		$	2,046
Gain on sales of real estate, net, per statements of operations	$	4		$	31		$	802		$	361		$	1,038
Add income taxes and minority interest	—			15			830			1,326			189
Gain on sales of real estate from discontinued operations	—			1,250			1,276			1,093			2,789
Combined gain on sales of real estate	4			1,296			2,908			2,780			4,016
Non-operational property sales and real estate services	(4		)	(46		)	(1,632		)	(1,687		)	(1,227		)
Gain on sales of depreciated real estate properties	$	—		$	1,250		$	1,276		$	1,093		$	2,789

(1) Includes income taxes from continuing operations, discontinued operations and gains on other sales of real estate (see components on page 36).

8

Quarterly Equity Analysis

(Amounts in thousands except per share data, share prices and ratios)

	2008									2007
	September 30			June 30			March 31			December 31			September 30
Common Equity - End of Quarter
Common Shares	51,530			47,702			47,616			47,366			47,345
Common Units	8,111			8,151			8,151			8,167			8,168
Total	59,641			55,853			55,768			55,533			55,513
End of Quarter Common Share Price	$	40.35		$	34.33		$	33.61		$	31.50		$	41.63
Market Value of Common Shares/Units	$	2,406,514		$	1,917,433		$	1,874,353		$	1,749,290		$	2,310,995
Common Shares Trading Volume
Average Daily Volume (Shares)	649			438			548			482			446
Average Daily Volume (Dollars in thousands)	$	24,908		$	16,222		$	16,981		$	17,714		$	18,121
As a Percentage of Weighted Average Common Shares	1.4		%	0.9		%	1.2		%	1.0		%	1.0		%
Common Share Price Range
Quarterly High	$	43.50		$	40.00		$	36.16		$	45.39		$	44.63
Quarterly Low	$	32.00		$	33.65		$	25.43		$	30.81		$	35.21
Quarterly Average	$	38.06		$	37.05		$	30.97		$	36.75		$	40.66
Convertible Preferred Equity - End of Quarter
Convertible Series I Preferred Units Outstanding	352			352			352			352			352
Conversion Ratio	0.5000			0.5000			0.5000			0.5000			0.5000
Common Shares Issued Assuming Conversion	176			176			176			176			176
Convertible Series K Preferred Shares Outstanding	532			532			532			532			532
Conversion Ratio	0.8163			0.8163			0.8163			0.8163			0.8163
Common Shares Issued Assuming Conversion	434			434			434			434			434
Nonconvertible Preferred Equity - End of Quarter
Redeemable Series G Shares Outstanding	2,200			2,200			2,200			2,200			2,200
Redeemable Series H Shares Outstanding	2,000			2,000			2,000			2,000			2,000
Redeemable Series J Shares Outstanding	3,390			3,390			3,390			3,390			3,390
Total Nonconvertible Preferred Equity	7,590			7,590			7,590			7,590			7,590
Total Convertible Preferred Equity	884			884			884			884			884
Total Preferred Equity	8,474			8,474			8,474			8,474			8,474
Nonconvertible Preferred Equity ($25 par value)
Redeemable Series G Shares	$	55,000		$	55,000		$	55,000		$	55,000		$	55,000
Redeemable Series H Shares	50,000			50,000			50,000			50,000			50,000
Redeemable Series J Shares	84,750			84,750			84,750			84,750			84,750
Total Nonconvertible Preferred Equity	$	189,750		$	189,750		$	189,750		$	189,750		$	189,750
Convertible Preferred Equity ($25 par value)
Convertible Series I Units	$	8,800		$	8,800		$	8,800		$	8,800		$	8,800
Convertible Preferred Equity ($50 par value)
Convertible Series K Shares	26,583			26,583			26,583			26,583			26,583
Total Convertible Preferred Equity	$	35,383		$	35,383		$	35,383		$	35,383		$	35,383
Total Recorded Book Value of Preferred Equity	$	225,133		$	225,133		$	225,133		$	225,133		$	225,133
Weighted Average Shares:
Common Shares Outstanding	47,273			47,110			47,001			46,947			46,781
Dilutive effect of share-based compensation awards	916			888			765			914			1,005
Common Units	8,130			8,151			8,154			8,167			8,297
Denominator for funds from operations per share - diluted	56,319			56,149			55,920			56,028			56,083
Capitalization
Recorded Book Value of Preferred Shares/Units	$	225,133		$	225,133		$	225,133		$	225,133		$	225,133
Market Value of Common Shares/Units	2,406,514			1,917,433			1,874,353			1,749,290			2,310,995
Total Equity Market Capitalization	$	2,631,648		$	2,142,567		$	2,099,487		$	1,974,423		$	2,536,128
Total Debt	$	1,856,280		$	1,904,351		$	1,845,968		$	1,825,842		$	1,799,912
Total Market Capitalization	$	4,487,928		$	4,046,918		$	3,945,455		$	3,800,265		$	4,336,040
Debt to Total Market Capitalization	41.4		%	47.1		%	46.8		%	48.0		%	41.5		%
Debt to Total Assets	59.9		%	63.3		%	62.9		%	62.3		%	61.7		%
Debt to Undepreciated Book Value of Real Estate Assets	58.3		%	60.9		%	61.1		%	60.8		%	60.5		%

9

Quarterly Debt Analysis

(Dollars in thousands)

	2008									2007
	September 30			June 30			March 31			December 31			September 30
Debt Outstanding
Mortgage Loans	$	1,193,659		$	1,099,830		$	1,144,879		$	1,160,753		$	1,169,094
Construction Loans	82,121			139,521			104,089			104,089			103,818
Unsecured Revolving Credit Facility	380,500			465,000			397,000			361,000			327,000
Exchangeable Senior Notes	200,000			200,000			200,000			200,000			200,000
	$	1,856,280		$	1,904,351		$	1,845,968		$	1,825,842		$	1,799,912
Average Outstanding Balance
Mortgage Loans	$	1,253,145		$	1,107,674		$	1,157,866		$	1,163,419		$	1,172,087
Construction Loans	78,842			126,186			104,089			104,084			95,025
Unsecured Revolving Credit Facility	421,587			435,238			377,420			352,043			312,792
Exchangeable Senior Notes	200,000			200,000			200,000			200,000			200,000
	$	1,953,574		$	1,869,098		$	1,839,375		$	1,819,546		$	1,779,904
Interest Rate Structure
Fixed-Mortgage Loans	$	972,259		$	1,065,330		$	1,110,379		$	1,126,253		$	1,134,594
Fixed-Exchangeable Senior Notes	200,000			200,000			200,000			200,000			200,000
Variable	534,021			489,021			385,589			349,589			365,318
Variable Subject to Interest Rate Protection (1) (2) (3)	150,000			150,000			150,000			150,000			100,000
	$	1,856,280		$	1,904,351		$	1,845,968		$	1,825,842		$	1,799,912
% of Fixed Rate Loans (4)	71.23		%	74.32		%	79.11		%	80.85		%	79.70		%
% of Variable Rate Loans (1) (2) (3)	28.77		%	25.68		%	20.89		%	19.15		%	20.30		%
	100.00		%	100.00		%	100.00		%	100.00		%	100.00		%
Average Contract Interest Rates
Mortgage & Construction Loans	5.50		%	5.60		%	5.81		%	5.96		%	6.01		%
Unsecured Revolving Credit Facility	4.25		%	4.24		%	4.93		%	5.79		%	6.72		%
Exchangeable Senior Notes	3.50		%	3.50		%	3.50		%	3.50		%	3.50		%
Total Weighted Average	5.11		%	5.11		%	5.42		%	5.74		%	5.89		%
Coverage Ratios (excluding capitalized interest) – All coverage computations include the effect of discontinued operations
Interest Coverage - Combined NOI	3.21		x	3.30		x	3.08		x	3.06		x	2.96		x
Interest Coverage - EBITDA	3.04		x	3.10		x	2.96		x	2.95		x	2.92		x
Debt Service Coverage - Combined NOI	2.75		x	2.79		x	2.59		x	2.51		x	2.49		x
Debt Service Coverage - EBITDA	2.61		x	2.62		x	2.49		x	2.41		x	2.46		x
Fixed Charge Coverage - Combined NOI	2.66		x	2.72		x	2.55		x	2.55		x	2.47		x
Fixed Charge Coverage - EBITDA	2.53		x	2.55		x	2.45		x	2.45		x	2.44		x

(1)On March 28, 2006, we entered into a $50.0 million notional amount swap at a fixed one-month LIBOR rate of 5.036%, which commenced on the same day and expires March 30, 2009.

(2)On April 27, 2006, we entered into two notional amount swaps aggregating $50.0 million at a fixed one-month LIBOR rate of 5.232%, which commenced May 1, 2006 and expire May 1, 2009.

(3)On October 23, 2007, we entered into a $50.0 million notional amount swap at a fixed one-month LIBOR rate of 4.330%, which commenced on the same day and expires October 23, 2009.

(4)Includes interest rate protection agreements.

10

Quarterly Operating Ratios

(Dollars in thousands except per share data and ratios)

	2008									2007
	September 30			June 30			March 31			December 31			September 30
OPERATING RATIOS — All computations include the effect of discontinued operations
Net Income as a % of Combined Real Estate Revenues (Net Income / Combined Real Estate Revenues)	12.74		%	13.09		%	11.70		%	10.44		%	12.05		%
Combined NOI as a % of Combined Real Estate Revenues (Combined NOI / Combined Real Estate Revenues)	64.72		%	65.41		%	64.35		%	67.01		%	65.98		%
EBITDA as a % of Combined Real Estate Revenues (EBITDA / Combined Real Estate Revenues)	61.36		%	61.44		%	61.74		%	64.40		%	65.15		%
G&A as a % of Net Income (G&A / Net Income)	47.13		%	46.96		%	52.07		%	57.99		%	50.24		%
G&A as a % of Combined Real Estate Revenues (G&A / Combined Real Estate Revenues)	6.00		%	6.15		%	6.09		%	6.05		%	6.06		%
G&A as a % of EBITDA (G&A / EBITDA)	9.78		%	10.01		%	9.86		%	9.40		%	9.30		%
Recurring Capital Expenditures	$	7,008		$	5,821		$	4,782		$	6,504		$	4,664
Recurring Capital Expenditures per average square foot of wholly owned properties	$	0.38		$	0.32		$	0.27		$	0.37		$	0.26
Recurring Capital Expenditures as a % of NOI (Combined NOI)	10.65		%	9.06		%	7.63		%	10.20		%	7.45		%

11

Quarterly Dividend Analysis

	2008									2007
	September 30			June 30			March 31			December 31			September 30
Common Share Dividends
Dividends per share/unit	$	0.3725		$	0.3400		$	0.3400		$	0.3400		$	0.3400
Increase over prior quarter	9.6		%	0.0		%	0.0		%	0.0		%	9.7		%
Common Dividend Payout Ratios
Payout - Earnings	215.0		%	183.5		%	219.4		%	272.6		%	217.3		%
Payout - FFO - Diluted	61.4		%	55.5		%	58.5		%	57.5		%	58.3		%
Payout - AFFO - Diluted	86.1		%	75.4		%	77.4		%	81.2		%	79.1		%
Dividend Coverage - FFO - Diluted	1.63		x	1.80		x	1.71		x	1.74		x	1.71		x
Dividend Coverage - AFFO - Diluted	1.16		x	1.33		x	1.29		x	1.23		x	1.26		x
Common Dividend Yields
Dividend Yield	3.69		%	3.96		%	4.05		%	4.32		%	3.27		%
Series I Preferred Unit Distributions
Preferred Unit Distributions Per Unit	$	0.46875		$	0.46875		$	0.46875		$	0.46875		$	0.46875
Preferred Unit Distributions Yield	7.500		%	7.500		%	7.500		%	7.500		%	7.500		%
Quarter End Recorded Book Value	$	25.00		$	25.00		$	25.00		$	25.00		$	25.00
Series G Preferred Share Dividends
Preferred Share Dividends Per Share	$	0.50000		$	0.50000		$	0.50000		$	0.50000		$	0.50000
Preferred Share Dividend Yield	8.000		%	8.000		%	8.000		%	8.000		%	8.000		%
Quarter End Recorded Book Value	$	25.00		$	25.00		$	25.00		$	25.00		$	25.00
Series H Preferred Share Dividends
Preferred Share Dividends Per Share	$	0.46875		$	0.46875		$	0.46875		$	0.46875		$	0.46875
Preferred Share Dividend Yield	7.500		%	7.500		%	7.500		%	7.500		%	7.500		%
Quarter End Recorded Book Value	$	25.00		$	25.00		$	25.00		$	25.00		$	25.00
Series J Preferred Share Dividends
Preferred Share Dividends Per Share	$	0.47656		$	0.47656		$	0.47656		$	0.47656		$	0.47656
Preferred Share Dividend Yield	7.625		%	7.625		%	7.625		%	7.625		%	7.625		%
Quarter End Recorded Book Value	$	25.00		$	25.00		$	25.00		$	25.00		$	25.00
Series K Preferred Share Dividends
Preferred Share Dividends Per Share	$	0.70000		$	0.70000		$	0.70000		$	0.70000		$	0.70000
Preferred Share Dividend Yield	5.600		%	5.600		%	5.600		%	5.600		%	5.600		%
Quarter End Recorded Book Value	$	50.00		$	50.00		$	50.00		$	50.00		$	50.00

12

Investor Composition and Analyst Coverage

(as of September 30, 2008)

			As if Converted		Fully Diluted
	Common	Common	Preferred		Ownership
	Shares	Units	Shares / Units	Total	% of Total
SHAREHOLDER CLASSIFICATION
Insiders	985,352	7,032,152	—	8,017,504	13.31	%
Non-insiders	50,544,810	1,079,142	610,014	52,233,966	86.69	%
	51,530,162	8,111,294	610,014	60,251,470	100.00	%

	September 30,	June 30,	March 31,	December 31,	September 30,
	2008	2008	2008	2007	2007
RESEARCH COVERAGE
A.G. Edwards	n/a	n/a	n/a	n/a	x
BMO Capital Markets	x	x	x	x	x
Citigroup Global Markets	x	x	x	x	x
Ferris, Baker Watts, Incorporated	n/a	n/a	x	x	x
Friedman Billings Ramsey & Co.	x	x	x	x	x
Green Street Advisors	x	x	x	x	x
Merrill Lynch	x	x	x	x	x
RBC Capital Markets	x	x	x	x	x
Raymond James	x	x	x	x	x
Robert W. Baird & Co. Incorporated	x	x	x	x	x
Stifel, Nicolaus & Company, Incorporated	x	x	x	x	x
Wachovia Securities	x	x	x	x	x

13

Debt Maturity Schedule - September 30, 2008

(Dollars in thousands)

		Non-Recourse Debt (1)						Recourse Debt (1)
Year of Maturity		Annual Amortization of Monthly Payments		Due on Maturity		Weighted Average Interest Rate of Amounts Maturing (2)		Annual Amortization of Monthly Payments		Due on Maturity		Weighted Average Interest Rate of Amounts Maturing (2)		Revolver (3)		Total Scheduled Payments
October - December		$	2,667	$	—	0.00	%	$	191	$	1,750	2.55	%	$	—	$	4,608
Total 2008		$	2,667	$	—	0.00	%	$	191	$	1,750	2.55	%	$	—	$	4,608
2009		$	9,620	$	52,228			$	795	$	40,589			$	—	$	103,232
2010	(4)	9,103		52,177				272		12,481				—		74,033
2011	(5)	7,309		102,264				241		41,532				380,500		531,846
2012		5,816		257,523				260		—				—		263,599
2013		2,593		134,843				282		—				—		137,718
2014	(6)	890		8,212				305		—				—		9,407
2015		552		114,558				329		—				—		115,439
2016		321		113,169				356		—				—		113,846
2017		193		300,610				385		—				—		301,188
2018		—		—				417		—				—		417
2019		—		—				373		39				—		412
		$	39,064	$	1,135,584			$	4,206	$	96,391			$	380,500	$	1,655,745
				Net premium to adjust to fair value of debt												535
				Mortgage and Other Loans Payable												$	1,656,280
				Exchangeable Senior Notes (7)												$	200,000
				Total Debt												$	1,856,280

Notes:

(1)	Certain mortgages contain extension options, generally either for a period of six months or one year, subject to certain conditions. The maturity dates presented above in the table assume that the extension options have not been exercised.
(2)	For the variable rate loans expiring in 2008, the interest rate used for this calculation was the rate at September 30, 2008.
(3)	As of October 29, 2008, our borrowing capacity under the Revolving Credit Facility was $600.0 million, of which $190.6 million was available.
(4)	Our $9.1 million non-recourse loan that matures in September 2025 will be called in October 2010. The above table includes the $8.5 million amount due on maturity in 2010.
(5)	Includes $41.5 million due under our Revolving Construction Facility at September 30, 2008. As of October 29, 2008, the borrowing capacity under this agreement totaled $140.6 million, of which $85.8 million was available.
(6)	We have a $4.8 million non-recourse loan maturing in March 2034 that may be prepaid in March 2014, subject to certain conditions. The above table includes $4.3 million due on maturity of this loan in 2014.
(7)	Exchangeable Senior Notes mature in September 2026 but are subject to a put by the holders in September 2011 and every five years thereafter.

14

Property Summary by Region - September 30, 2008

Wholly Owned Properties

Operating Property Count		Submarket	Business Park	Year Built or  Renovated	S or M	Total  Operational  Square Feet	Total Square Feet  Under  Construction /  Redevelopment
	Office Properties
	Baltimore /Washington Corridor
1	2730 Hercules Road	BWI Airport	NBP	1990	M	240,336
	300 Sentinel Drive (300 NBP)	BWI Airport	NBP		M		185,719
2	304 Sentinel Drive (304 NBP)	BWI Airport	NBP	2005	M	162,498
3	306 Sentinel Drive (306 NBP)	BWI Airport	NBP	2006	M	157,896
4	2720 Technology Drive (220 NBP)	BWI Airport	NBP	2004	M	156,730
5	302 Sentinel Drive (302 NBP)	BWI Airport	NBP	2007	M	155,731
6	2711 Technology Drive (211 NBP)	BWI Airport	NBP	2002	M	152,000
7	320 Sentinel Way (320 NBP)	BWI Airport	NBP	2007	M	125,681
8	318 Sentinel Way (318 NBP)	BWI Airport	NBP	2005	M	125,681
9	322 Sentinel Way (322 NBP)	BWI Airport	NBP	2006	M	125,568
10	140 National Business Parkway	BWI Airport	NBP	2003	M	119,904
11	132 National Business Parkway	BWI Airport	NBP	2000	M	118,598
12	2721 Technology Drive (221 NBP)	BWI Airport	NBP	2000	M	118,093
13	2701 Technology Drive (201 NBP)	BWI Airport	NBP	2001	M	117,450
14	2691 Technology Drive (191 NBP)	BWI Airport	NBP	2005	M	103,683
15	134 National Business Parkway	BWI Airport	NBP	1999	M	93,482
16	135 National Business Parkway	BWI Airport	NBP	1998	M	87,655
17	133 National Business Parkway	BWI Airport	NBP	1997	M	87,401
18	141 National Business Parkway	BWI Airport	NBP	1990	M	87,206
19	131 National Business Parkway	BWI Airport	NBP	1990	M	69,039
20	114 National Business Parkway	BWI Airport	NBP	2002	S	9,908
						2,414,540	185,719
1	1306 Concourse Drive	BWI Airport	APS	1990	M	114,046
2	870-880 Elkridge Landing Road	BWI Airport	APS	1981	M	105,151
3	1304 Concourse Drive	BWI Airport	APS	2002	M	101,753
4	900 Elkridge Landing Road	BWI Airport	APS	1982	M	97,261
5	1199 Winterson Road	BWI Airport	APS	1988	M	96,636
6	920 Elkridge Landing Road	BWI Airport	APS	1982	M	96,566
7	1302 Concourse Drive	BWI Airport	APS	1996	M	84,505
8	881 Elkridge Landing Road	BWI Airport	APS	1986	M	73,572
9	1099 Winterson Road	BWI Airport	APS	1988	M	70,569
10	1190 Winterson Road	BWI Airport	APS	1987	M	69,127
11	849 International Drive	BWI Airport	APS	1988	M	68,791
12	911 Elkridge Landing Road	BWI Airport	APS	1985	M	68,296
13	1201 Winterson Road	BWI Airport	APS	1985	M	67,903
14	999 Corporate Boulevard	BWI Airport	APS	2000	M	67,455
15	891 Elkridge Landing Road	BWI Airport	APS	1984	M	58,454
16	901 Elkridge Landing Road	BWI Airport	APS	1984	M	57,628
17	930 International Drive	BWI Airport	APS	1986	S	57,409
18	800 International Drive	BWI Airport	APS	1988	S	57,379
19	900 International Drive	BWI Airport	APS	1986	S	57,140
20	921 Elkridge Landing Road	BWI Airport	APS	1983	M	54,175
21	939 Elkridge Landing Road	BWI Airport	APS	1983	M	53,218
22	938 Elkridge Landing Road	BWI Airport	APS	1984	M	52,988
						1,630,022	—
1	7467 Ridge Road	BWI Airport	Comm./Pkwy.	1990	M	74,326
2	7240 Parkway Drive	BWI Airport	Comm./Pkwy.	1985	M	74,160
3	7272 Park Circle Drive	BWI Airport	Comm./Pkwy.	1991/1996	M	59,436
4	7318 Parkway Drive	BWI Airport	Comm./Pkwy.	1984	S	59,204
5	7320 Parkway Drive	BWI Airport	Comm./Pkwy.	1983	S	58,453
6	1340 Ashton Road	BWI Airport	Comm./Pkwy.	1989	S	46,400
7	1362 Mellon Road	BWI Airport	Comm./Pkwy.	2006	M	44,134
8	1334 Ashton Road	BWI Airport	Comm./Pkwy.	1989	S	37,565
9	1331 Ashton Road	BWI Airport	Comm./Pkwy.	1989	S	29,153
10	1350 Dorsey Road	BWI Airport	Comm./Pkwy.	1989	S	19,992
11	1344 Ashton Road	BWI Airport	Comm./Pkwy.	1989	M	17,062
12	1341 Ashton Road	BWI Airport	Comm./Pkwy.	1989	S	15,841
13	1343 Ashton Road	BWI Airport	Comm./Pkwy.	1989	S	9,962
14	1348 Ashton Road	BWI Airport	Comm./Pkwy.	1988	S	3,108
						548,796	—
56	Subtotal (continued on next page)					4,593,358	185,719

The S or M notation indicates single story or multi-story, respectively.

15

Property Summary by Region - September 30, 2008 (continued)

Wholly Owned Properties

Operating Property Count		Submarket	Business Park	Year Built or  Renovated	S or M	Total  Operational  Square Feet	Total Square Feet  Under  Construction /  Redevelopment
56	Subtotal (continued from prior page)					4,593,358	185,719
	5520 Research Park Drive (UMBC) (1)	BWI Airport	bwtech@UMBC		M		105,964
1	5522 Research Park Drive (UMBC) (1)	BWI Airport	bwtech@UMBC	2007	S	23,500
						23,500	105,964
1	2500 Riva Road	Annapolis		2000	M	155,000
1	Old Annapolis Road	Howard Co. Perimeter	Oakland Ridge	1985	M	171,436
1	7125 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	1973/1999	M	611,379
2	7000 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	1999	M	145,806
	6721 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway		M		131,451
3	6731 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	2002	M	123,911
4	6711 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	2006-2007	M	123,410
5	6940 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	1999	M	109,003
6	6950 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	1998	M	107,778
7	7067 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	2001	M	86,055
8	8621 Robert Fulton Drive	Howard Co. Perimeter	Columbia Gateway	2005-2006	M	86,033
9	6750 Alexander Bell Drive	Howard Co. Perimeter	Columbia Gateway	2001	M	79,135
10	6700 Alexander Bell Drive	Howard Co. Perimeter	Columbia Gateway	1988	M	74,852
11	6740 Alexander Bell Drive	Howard Co. Perimeter	Columbia Gateway	1992	M	63,480
12	7015 Albert Einstein Drive	Howard Co. Perimeter	Columbia Gateway	1999	S	61,203
13	8671 Robert Fulton Drive	Howard Co. Perimeter	Columbia Gateway	2002	S	56,350
14	6716 Alexander Bell Drive	Howard Co. Perimeter	Columbia Gateway	1990	M	52,203
15	8661 Robert Fulton Drive	Howard Co. Perimeter	Columbia Gateway	2002	S	49,307
16	7142 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	1994	S	47,668
17	7130 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	1989	S	46,460
18	6708 Alexander Bell Drive	Howard Co. Perimeter	Columbia Gateway	1988	M	39,203
19	7065 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	2000	S	38,560
20	7138 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	1990	S	38,225
21	7063 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	2000	S	36,813
22	6760 Alexander Bell Drive	Howard Co. Perimeter	Columbia Gateway	1991	M	36,440
23	7150 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	1991	S	35,812
24	7061 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	2000	M	29,910
25	6724 Alexander Bell Drive	Howard Co. Perimeter	Columbia Gateway	2001	M	28,420
26	7134 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	1990	S	21,991
27	6741 Columbia Gateway Drive	Howard Co. Perimeter	Columbia Gateway	2008	S	4,592
						2,233,999	131,451
1	7200 Riverwood Drive	Howard Co. Perimeter	Rivers Corporate Park	1986	S	160,000
2	7160 Riverwood Drive	Howard Co. Perimeter	Rivers Corporate Park	2000	M	62,084
3	9140 Guilford Road	Howard Co. Perimeter	Rivers Corporate Park	1983	S	41,704
4	7150 Riverwood Drive	Howard Co. Perimeter	Rivers Corporate Park	2000	M	41,382
5	9160 Guilford Road	Howard Co. Perimeter	Rivers Corporate Park	1984	M	37,034
6	7170 Riverwood Drive	Howard Co. Perimeter	Rivers Corporate Park	2000	M	29,162
7	9150 Guilford Road	Howard Co. Perimeter	Rivers Corporate Park	1984	S	18,592
8	10280 Old Columbia Road	Howard Co. Perimeter	Rivers Corporate Park	1988/2001	S	16,796
9	10270 Old Columbia Road	Howard Co. Perimeter	Rivers Corporate Park	1988/2001	S	16,686
10	9130 Guilford Road	Howard Co. Perimeter	Rivers Corporate Park	1984	S	13,700
11	10290 Old Columbia Road	Howard Co. Perimeter	Rivers Corporate Park	1988/2001	S	10,890
						448,030	—
1	9720 Patuxent Woods Drive	Howard Co. Perimeter	Owen Brown South	1986/2001	M	40,004
2	9740 Patuxent Woods Drive	Howard Co. Perimeter	Owen Brown South	1986/2001	M	38,292
3	9700 Patuxent Woods Drive	Howard Co. Perimeter	Owen Brown South	1986/2001	M	31,261
4	9730 Patuxent Woods Drive	Howard Co. Perimeter	Owen Brown South	1986/2001	M	31,012
5	9710 Patuxent Woods Drive	Howard Co. Perimeter	Owen Brown South	1986/2001	M	15,229
						155,798	—
1	9020 Mendenhall Court	Howard Co. Perimeter	Sieling Business Park	1982/2005	S	49,259
103	Total Baltimore/Washington Corridor					7,830,380	423,134

The S or M notation indicates single story or multi-story building, respectively.

(1) This property is a land-lease property.

16

Property Summary by Region - September 30, 2008 (continued)

Wholly Owned Properties

Operating Property Count		Submarket	Business Park	Year Built or  Renovated	S or M	Total  Operational  Square Feet	Total Square Feet  Under  Construction /  Redevelopment
	St. Mary’s & King George Counties
1	22309 Exploration Drive	St. Mary’s County	Exploration Park	1984/1997	M	98,860
2	22289 Exploration Drive	St. Mary’s County	Exploration Park	2000	M	61,059
3	22299 Exploration Drive	St. Mary’s County	Exploration Park	1998	M	58,231
4	22300 Exploration Drive	St. Mary’s County	Exploration Park	1997	M	44,830
						262,980	—
1	46579 Expedition Drive	St. Mary’s County	Expedition Park	2002	M	61,156
2	46591 Expedition Drive	St. Mary’s County	Expedition Park	2005-2006	M	59,483
						120,639	—
1	44425 Pecan Court	St. Mary’s County	Wildewood Tech Park	1997	M	59,055
2	44408 Pecan Court	St. Mary’s County	Wildewood Tech Park	1986	S	50,532
3	23535 Cottonwood Parkway	St. Mary’s County	Wildewood Tech Park	1984	M	46,656
4	44417 Pecan Court	St. Mary’s County	Wildewood Tech Park	1989	S	29,053
5	44414 Pecan Court	St. Mary’s County	Wildewood Tech Park	1986	S	25,444
6	44420 Pecan Court	St. Mary’s County	Wildewood Tech Park	1989	S	25,200
						235,940	—
1	16480 Commerce Drive	King George County	Dahlgren Technology Center	2000	M	70,728
2	16541 Commerce Drive	King George County	Dahlgren Technology Center	1996	S	36,053
3	16539 Commerce Drive	King George County	Dahlgren Technology Center	1990	S	32,076
4	16442 Commerce Drive	King George County	Dahlgren Technology Center	2002	S	25,518
5	16501 Commerce Drive	King George County	Dahlgren Technology Center	2002	S	22,833
6	16543 Commerce Drive	King George County	Dahlgren Technology Center	2002	S	17,370
						204,578	—
18	Total St. Mary’s & King George Counties					824,137	—
	Northern Virginia
1	15000 Conference Center Drive	Dulles South	Westfields	1989	M	470,406
2	15010 Conference Center Drive	Dulles South	Westfields	2006	M	223,610
3	15059 Conference Center Drive	Dulles South	Westfields	2000	M	145,224
4	15049 Conference Center Drive	Dulles South	Westfields	1997	M	145,053
5	14900 Conference Center Drive	Dulles South	Westfields	1999	M	127,857
6	14280 Park Meadow Drive	Dulles South	Westfields	1999	M	114,126
7	4851 Stonecroft Boulevard	Dulles South	Westfields	2004	M	88,094
8	14850 Conference Center Drive	Dulles South	Westfields	2000	M	69,711
9	14840 Conference Center Drive	Dulles South	Westfields	2000	M	69,710
						1,453,791	—
1	13200 Woodland Park Road	Herndon	Woodland	2002	M	404,665
1	13454 Sunrise Valley Road	Herndon	Dulles Tech	1998	M	112,633
2	13450 Sunrise Valley Road	Herndon	Dulles Tech	1998	M	53,728
						166,361	—
1	1751 Pinnacle Drive	Tysons Corner		1989/1995	M	260,469
2	1753 Pinnacle Drive	Tysons Corner		1976/2004	M	186,707
						447,176	—
14	Total Northern Virginia					2,471,993	—
	Other
1	11751 Meadowville Lane	Richmond Southwest	Meadowville Technology Park	2007	M	193,000
1	201 Technology Park Drive	Southwest Virginia	Russell Regional Business Tech Park	2007	S	102,842
1	607 Lakeside Drive	Fort Ritchie		1990/2007	S	6,370
2	304 Castle Drive	Fort Ritchie		1993/2008	S	3,014
						9,384	—
4	Total Other					305,226	—

The S or M notation indicates single story or multi-story building, respectively.

17

Property Summary by Region - September 30, 2008 (continued)

Wholly Owned Properties

Operating  Property  Count		Submarket	Business Park	Year Built or  Renovated	S or M	Total  Operational  Square Feet	Total Square Feet Under  Construction /  Redevelopment
	Greater Philadelphia
1	753 Jolly Road	Blue Bell	Unisys campus	1992	S	418,430
2	785 Jolly Road	Blue Bell	Unisys campus	1996	M	219,065
3	760 Jolly Road	Blue Bell	Unisys campus	1994	M	208,854
4	751 Jolly Road	Blue Bell	Unisys campus	1991	M	114,000
	Total Greater Philadelphia					960,349	—
	Central New Jersey
1	431 Ridge Road	Exit 8A — Cranbury	Princeton Tech Cntr.	1998	S	171,200
2	437 Ridge Road	Exit 8A — Cranbury	Princeton Tech Cntr.	1996	S	30,000
	Total Central New Jersey					201,200	—
	San Antonio, Texas
2	7700 Potranco Road	San Antonio Northwest		1982/1985	M	468,994	90,607
3	7700-1 Potranco Road	San Antonio Northwest		2007	S	8,674
						477,668	90,607
1	1560 Cable Ranch Road - Building B	San Antonio Northwest	151 Technology Center	1985/2006	M	77,040
2	1560 Cable Ranch Road - Building A	San Antonio Northwest	151 Technology Center	1985/2007	M	45,935
						122,975	—
5	Total San Antonio, Texas					600,643	90,607
	Colorado Springs, Colorado
1	655 Space Center Drive	Colorado Springs East	Patriot Park	2008	M	103,970
2	985 Space Center Drive	Colorado Springs East	Patriot Park	1989	M	102,821
	565 Space Center Drive	Colorado Springs East	Patriot Park		M		89,773
3	745 Space Center Drive	Colorado Springs East	Patriot Park	2006	M	51,500
4	980 Technology Court	Colorado Springs East	Patriot Park	1995	S	33,190
5	525 Babcock Road	Colorado Springs East	Patriot Park	1967	S	14,000
						305,481	89,773
1	1055 North Newport Road	Colorado Springs East	Aerotech Commerce Park	2007-2008	M	59,763
1	3535 Northrop Grumman Point	Colorado Springs East	Colorado Springs Airport	2008	M	124,305
1	1670 North Newport Road	Colorado Springs East		1986-1987	M	67,500
2	1915 Aerotech Drive	Colorado Springs East		1985	S	37,946
3	1925 Aerotech Drive	Colorado Springs East		1985	S	37,946
						143,392	—
	10807 New Allegiance Drive	I-25 North Corridor	InterQuest Office		M		145,723
1	9965 Federal Drive	I-25 North Corridor	InterQuest Office	1983/2007	M	74,749
	9945 Federal Drive	I-25 North Corridor	InterQuest Office		S		73,940
2	9950 Federal Drive	I-25 North Corridor	InterQuest Office	2001	S	66,222
3	9925 Federal Drive	I-25 North Corridor	InterQuest Office		S	43,721	10,024
4	9960 Federal Drive	I-25 North Corridor	InterQuest Office	2001	S	46,948
						231,640	229,687
1	5775 Mark Dabling Boulevard	Colorado Springs Northwest		1984	M	109,678
2	5725 Mark Dabling Boulevard	Colorado Springs Northwest		1984	M	108,976
3	5755 Mark Dabling Boulevard	Colorado Springs Northwest		1989	M	105,788
						324,442	—
17	Total Colorado Springs, Colorado					1,189,023	319,460

The S or M notation indicates single story or multi-story building, respectively.

18

Property Summary by Region - September 30, 2008 (continued)

Wholly Owned Properties

Operating Property Count		Submarket	Business Park	Year Built or Renovated	S or M	Total Operational Square Feet	Total Square Feet Under Construction / Redevelopment
	Suburban Maryland
1	11800 Tech Road	North Silver Spring	Montgomery Industrial	1989	M	228,179
1	400 Professional Drive	Gaithersburg	Crown Point	2000	M	129,311
1	110 Thomas Johnson Drive	Frederick		1987/1999	M	121,704
1	45 West Gude Drive	Rockville		1987	M	108,588
2	15 West Gude Drive	Rockville		1986	M	106,694
						215,282	—
5	Total Suburban Maryland
						694,476	—
	Suburban Baltimore
1	11311 McCormick Road	Hunt Valley/Rte 83 Corridor	Hunt Valley Business Comm.	1984/1994	M	215,064
2	200 International Circle	Hunt Valley/Rte 83 Corridor	Hunt Valley Business Comm.	1987	M	127,196
3	226 Schilling Circle	Hunt Valley/Rte 83 Corridor	Hunt Valley Business Comm.	1980	M	98,640
4	201 International Circle	Hunt Valley/Rte 83 Corridor	Hunt Valley Business Comm.	1982	M	78,461
5	11011 McCormick Road	Hunt Valley/Rte 83 Corridor	Hunt Valley Business Comm.	1974	M	56,512
6	216 Schilling Circle	Hunt Valley/Rte 83 Corridor	Hunt Valley Business Comm.	1988/2001	M	36,003
7	222 Schilling Circle	Hunt Valley/Rte 83 Corridor	Hunt Valley Business Comm.	1978/1997	M	28,003
8	224 Schilling Circle	Hunt Valley/Rte 83 Corridor	Hunt Valley Business Comm.	1978/1997	M	27,372
9	11101 McCormick Road	Hunt Valley/Rte 83 Corridor	Hunt Valley Business Comm.	1976	S	24,232
						691,483	—
1	10150 York Road	Hunt Valley/Rte 83 Corridor		1985	M	178,286
2	9690 Deereco Road	Hunt Valley/Rte 83 Corridor		1988	M	134,167
3	375 West Padonia Road	Hunt Valley/Rte 83 Corridor		1986	M	110,328
						422,781	—
1	7210 Ambassador Road	Baltimore County Westside	Rutherford Business Center	1972	S	83,435
2	7152 Windsor Boulevard	Baltimore County Westside	Rutherford Business Center	1986	S	57,855
3	21 Governor’s Court	Baltimore County Westside	Rutherford Business Center	1981/1995	M	56,714
4	7125 Ambassador Road	Baltimore County Westside	Rutherford Business Center	1985	M	50,488
5	7104 Ambassador Road	Baltimore County Westside	Rutherford Business Center	1988	M	30,257
6	17 Governor’s Court	Baltimore County Westside	Rutherford Business Center	1981	S	14,619
7	15 Governor’s Court	Baltimore County Westside	Rutherford Business Center	1981	S	14,568
8	7127 Ambassador Road	Baltimore County Westside	Rutherford Business Center	1985	S	11,630
9	7129 Ambassador Road	Baltimore County Westside	Rutherford Business Center	1985	S	11,075
10	7108 Ambassador Road	Baltimore County Westside	Rutherford Business Center	1988	S	9,018
11	7102 Ambassador Road	Baltimore County Westside	Rutherford Business Center	1988	S	8,879
12	7106 Ambassador Road	Baltimore County Westside	Rutherford Business Center	1988	S	8,858
13	7131 Ambassador Road	Baltimore County Westside	Rutherford Business Center	1985	S	7,453
						364,849	—
1	502 Washington Avenue	Towson		1984	M	91,343
2	102 West Pennsylvania Avenue	Towson		1968/2001	M	49,497
3	100 West Pennsylvania Avenue	Towson		1952/1989	M	18,715
4	109-111 Allegheny Avenue	Towson		1971	M	18,431
						177,986	—
29	Subtotal (continued on next page)					1,657,099	—

The S or M notation indicates single story or multi-story building, respectively.

19

Property Summary by Region - September 30, 2008 (continued)

Wholly Owned Properties

Operating Property Count		Submarket	Business Park	Year Built or Renovated	S or M	Total Operational Square Feet	Total Square Feet Under Construction / Redevelopment
29	Subtotal (continued from prior page)					1,657,099	—
1	4940 Campbell Boulevard	White Marsh	Campbell Corporate Center	1990	M	49,779
1	8140 Corporate Drive	White Marsh	Corporate Place	2003	M	76,116
2	8110 Corporate Drive	White Marsh	Corporate Place	2001	M	75,687
						151,803	—
1	9910 Franklin Square Drive	White Marsh	Franklin Ridge	2005	S	56,271
2	9920 Franklin Square Drive	White Marsh	Franklin Ridge	2006	S	44,566
3	9930 Franklin Square Drive	White Marsh	Franklin Ridge	2001	S	39,750
4	9900 Franklin Square Drive	White Marsh	Franklin Ridge	1999	S	33,912
5	9940 Franklin Square Drive	White Marsh	Franklin Ridge	2000	S	32,293
						206,792	—
1	8020 Corporate Drive	White Marsh	McLean Ridge	1997	S	51,600
2	8094 Sandpiper Circle	White Marsh	McLean Ridge	1998	S	50,812
3	8098 Sandpiper Circle	White Marsh	McLean Ridge	1998	S	47,680
4	8010 Corporate Drive	White Marsh	McLean Ridge	1998	S	39,351
						189,443	—
1	5325 Nottingham Ridge Road	White Marsh	Nottingham Ridge	2002	S	36,626
1	7941-7949 Corporate Drive	White Marsh	Tyler Ridge	1996	S	57,600
2	8007 Corporate Drive	White Marsh	Tyler Ridge	1995	S	43,068
3	8019 Corporate Drive	White Marsh	Tyler Ridge	1990	S	33,274
4	8013 Corporate Drive	White Marsh	Tyler Ridge	1990	S	30,003
5	8003 Corporate Drive	White Marsh	Tyler Ridge	1999	S	18,327
6	8015 Corporate Drive	White Marsh	Tyler Ridge	1990	S	16,610
7	8023 Corporate Drive	White Marsh	Tyler Ridge	1990	S	9,486
						208,368	—
1	5020 Campbell Boulevard	White Marsh	White Marsh Business Center	1986-1988	S	44,362
2	5024 Campbell Boulevard	White Marsh	White Marsh Business Center	1986-1988	S	33,858
3	5026 Campbell Boulevard	White Marsh	White Marsh Business Center	1986-1988	S	30,868
4	5022 Campbell Boulevard	White Marsh	White Marsh Business Center	1986-1988	S	27,358
						136,446	—
1	10001 Franklin Square Drive	White Marsh	White Marsh Commerce Center	1997	S	216,915
1	8114 Sandpiper Circle	White Marsh	White Marsh Health Center	1986	S	44,990
1	4979 Mercantile Road	White Marsh	White Marsh Hi-Tech Center	1985	S	50,498
2	4969 Mercantile Road	White Marsh	White Marsh Hi-Tech Center	1983	S	47,574
						98,072	—
1	7939 Honeygo Boulevard	White Marsh	White Marsh Professional Center	1984	M	28,066
2	8133 Perry Hall Boulevard	White Marsh	White Marsh Professional Center	1988	M	27,860
3	7923 Honeygo Boulevard	White Marsh	White Marsh Professional Center	1985	M	24,054
						79,980	—
1	8031 Corporate Drive	White Marsh		1988/2004	S	66,000
2	8615 Ridgely’s Choice Drive	White Marsh		2005	M	37,840
3	8029 Corporate Drive	White Marsh		1988/2004	S	25,000
						128,840	—
63	Total Suburban Baltimore					3,205,153	—
235	TOTAL WHOLLY-OWNED PORTFOLIO					18,282,580	833,201

The S or M notation indicates single story or multi-story building, respectively.

20

Property Summary by Region - September 30, 2008

Joint Venture Properties

Operating Property Count		Submarket	Business Park	Year Built or Renovated	S or M	Total Operational Square Feet	Total Square Feet Under Construction / Redevelopment
	Unconsolidated Joint Venture Properties
	Greater Harrisburg
1	2605 Interstate Drive	East Shore	Commerce Park	1990	M	79,456
2	2601 Market Place	East Shore	Commerce Park	1989	M	65,411
						144,867	—
1	6345 Flank Drive	East Shore	Gtwy Corp. Ctr.	1989	S	69,443
2	6340 Flank Drive	East Shore	Gtwy Corp. Ctr.	1988	S	68,200
3	6400 Flank Drive	East Shore	Gtwy Corp. Ctr.	1992	S	52,439
4	6360 Flank Drive	East Shore	Gtwy Corp. Ctr.	1988	S	46,500
5	6385 Flank Drive	East Shore	Gtwy Corp. Ctr.	1995	S	32,921
6	6380 Flank Drive	East Shore	Gtwy Corp. Ctr.	1991	S	32,668
7	6405 Flank Drive	East Shore	Gtwy Corp. Ctr.	1991	S	32,000
8	95 Shannon Road	East Shore	Gtwy Corp. Ctr.	1999	S	21,976
9	75 Shannon Road	East Shore	Gtwy Corp. Ctr.	1999	S	20,887
10	6375 Flank Drive	East Shore	Gtwy Corp. Ctr.	2000	S	19,783
11	85 Shannon Road	East Shore	Gtwy Corp. Ctr.	1999	S	12,863
						409,680	—
1	5035 Ritter Road	West Shore	Rossmoyne Bus. Ctr.	1988	S	56,556
2	5070 Ritter Road - Building A	West Shore	Rossmoyne Bus. Ctr.	1989	S	32,309
3	5070 Ritter Road - Building B	West Shore	Rossmoyne Bus. Ctr.	1989	S	28,347
						117,212	—
16	Total Greater Harrisburg					671,759	—
16	Total Unconsolidated Joint Venture Properties					671,759	—
	Consolidated Joint Venture Properties
	Suburban Maryland
1	5825 University Research Court	College Park	M Square Business Park	2008	M	41,500	74,583
	5850 University Research Court	College Park	M Square Business Park		M		123,464
						41,500	198,047
1	4230 Forbes Boulevard	Lanham	Forbes 50	2003	S	55,866
	Total Suburban Maryland					97,366	198,047
	Baltimore/Washington Corridor
	7468 Candlewood Road	BWI Airport	Baltimore Commons	1979/1982	M		356,000
	7740 Milestone Parkway	BWI Airport	Arundel Preserve		M		148,130
	Total Baltimore/Washington Corridor					—	504,130
	Northern Virginia
1	2900 Towerview Road	Route 28 South	Renaissance Park	1982	M	78,171	58,866
	13849 Park Center Road	Route 28 South	Renaissance Park	1982	M		4,265
	Total Northern Virginia					78,171	63,131
3	Total Consolidated Joint Venture Properties					175,537	765,308
19	TOTAL JOINT VENTURE PORTFOLIO					847,296	765,308

The S or M notation indicates single story or multi-story building, respectively.

21

Property Occupancy Rates by Region by Quarter

Wholly Owned Properties

	Baltimore /								St. Mary’s &
	Washington		Northern		Suburban		Suburban		King George		Colorado		San		Greater		Central				Total
	Corridor		Virginia		Baltimore		Maryland		Counties		Springs		Antonio		Philadelphia		New Jersey		Other		Portfolio
September 30, 2008
Number of Buildings	103		14		63		5		18		17		5		4		2		4		235
Rentable Square Feet	7,830,380		2,471,993		3,205,153		694,476		824,137		1,189,023		600,643		960,349		201,200		305,226		18,282,580
Occupied %	92.38	%	99.20	%	84.28	%	97.18	%	93.48	%	95.30	%	100.00	%	100.00	%	100.00	%	100.00	%	93.17	%
Leased %	93.33	%	99.34	%	87.81	%	97.18	%	95.31	%	95.30	%	100.00	%	100.00	%	100.00	%	100.00	%	94.29	%
June 30, 2008
Number of Buildings	103		14		63		5		18		16		5		4		2		4		234
Rentable Square Feet	7,824,771		2,466,923		3,205,931		690,575		824,137		1,144,724		600,643		960,349		201,200		305,226		18,224,479
Occupied %	92.48	%	99.34	%	85.49	%	97.58	%	92.98	%	94.90	%	100.00	%	100.00	%	100.00	%	100.00	%	93.40	%
Leased %	93.35	%	99.34	%	87.16	%	97.73	%	95.26	%	95.32	%	100.00	%	100.00	%	100.00	%	100.00	%	94.20	%
March 31, 2008
Number of Buildings	101		14		64		5		18		14		3		4		3		4		230
Rentable Square Feet	7,778,724		2,466,923		3,245,225		690,575		824,683		916,449		477,668		960,349		242,598		305,226		17,908,420
Occupied %	91.89	%	99.34	%	83.84	%	97.58	%	93.20	%	96.73	%	100.00	%	100.00	%	100.00	%	100.00	%	92.89	%
Leased %	93.39	%	99.34	%	86.57	%	97.58	%	94.09	%	96.73	%	100.00	%	100.00	%	100.00	%	100.00	%	94.07	%
December 31, 2007
Number of Buildings	101		14		64		5		18		13		2		4		4		3		228
Rentable Square Feet	7,668,383		2,466,149		3,243,814		690,575		824,683		822,953		468,994		960,349		384,983		300,746		17,831,629
Occupied %	92.59	%	98.60	%	84.77	%	97.80	%	91.55	%	96.66	%	100.00	%	100.00	%	70.82	%	100.00	%	92.59	%
Leased %	93.13	%	98.77	%	87.39	%	98.28	%	93.34	%	96.66	%	100.00	%	100.00	%	70.82	%	100.00	%	93.42	%
September 30, 2007
Number of Buildings	101		14		66		5		18		13		2		4		4		2		229
Rentable Square Feet	7,569,985		2,466,149		3,336,709		690,575		824,683		821,453		468,994		960,349		384,983		197,904		17,721,784
Occupied %	93.46	%	99.23	%	83.87	%	97.80	%	92.32	%	96.05	%	100.00	%	100.00	%	70.82	%	100.00	%	92.80	%
Leased %	93.85	%	99.33	%	84.69	%	97.80	%	94.11	%	96.05	%	100.00	%	100.00	%	70.82	%	100.00	%	93.22	%

22

Property Occupancy Rates by Region by Quarter

Joint Venture Properties

	Unconsolidated		Consolidated
	Greater		Suburban		Northern		Total
	Harrisburg		Maryland		Virginia		Portfolio
September 30, 2008
Number of Buildings	16		2		1		19
Rentable Square Feet	671,759		97,366		78,171		847,296
Occupied %	89.90	%	90.68	%	100.00	%	90.92	%
Leased %	90.40	%	94.79	%	100.00	%	91.79	%
June 30, 2008
Number of Buildings	16		2		1		19
Rentable Square Feet	671,759		97,366		78,171		847,296
Occupied %	89.88	%	86.32	%	100.00	%	90.41	%
Leased %	89.88	%	86.32	%	100.00	%	90.41	%
March 31, 2008
Number of Buildings	16		1		1		18
Rentable Square Feet	671,759		55,866		78,171		805,796
Occupied %	89.64	%	76.15	%	100.00	%	89.71	%
Leased %	89.88	%	76.15	%	100.00	%	89.91	%
December 31, 2007
Number of Buildings	16		1		1		18
Rentable Square Feet	671,759		55,866		78,171		805,796
Occupied %	90.46	%	76.15	%	100.00	%	90.39	%
Leased %	90.46	%	76.15	%	100.00	%	90.39	%
September 30, 2007
Number of Buildings	16		1		1		18
Rentable Square Feet	671,759		55,866		78,171		805,796
Occupied %	90.46	%	76.15	%	100.00	%	90.39	%
Leased %	90.46	%	76.15	%	100.00	%	90.39	%

Reconciliation of Wholly Owned Properties to Entire

Portfolio as of September 30, 2008

		Square
	Count	Feet	Occupied %		Leased %
Wholly Owned Properties	235	18,282,580	93.17	%	94.29	%
Add: Consolidated Joint Venture Properties	3	175,537	94.83	%	97.11	%
Subtotal	238	18,458,117	93.18	%	94.32	%
Add: Unconsolidated Joint Venture Properties	16	671,759	89.90	%	90.40	%
Entire Portfolio	254	19,129,876	93.07	%	94.18	%

23

Top Twenty Office Tenants of Wholly Owned Properties as of September 30, 2008 (1)

(Dollars in thousands)

				Percentage of		Total		Percentage		Weighted
			Total	Total		Annualized		of Total		Average
		Number of	Occupied	Occupied		Rental		Annualized Rental		Remaining
Tenant		Leases	Square Feet	Square Feet		Revenue (2) (3)		Revenue		Lease Term (4)
United States of America	(5)	66	2,496,636	14.7	%	$	60,530	16.0	%	6.3
Northrop Grumman Corporation	(6)	16	1,139,591	6.7	%	28,457		7.5	%	7.5
Booz Allen Hamilton, Inc.		8	710,692	4.2	%	19,932		5.3	%	5.8
Computer Sciences Corporation	(6)	4	454,533	2.7	%	11,875		3.1	%	2.8
L-3 Communications Holdings, Inc.	(6)	5	267,354	1.6	%	9,590		2.5	%	5.5
Unisys Corporation	(7)	5	760,145	4.5	%	9,048		2.4	%	2.5
General Dynamics Corporation	(6)	9	288,600	1.7	%	7,668		2.0	%	1.9
The Aerospace Corporation		3	245,598	1.4	%	7,268		1.9	%	6.4
ITT Corporation	(6)	14	290,312	1.7	%	6,833		1.8	%	5.6
Wachovia Corporation	(6)	4	183,577	1.1	%	6,613		1.8	%	9.9
Comcast Corporation	(6)	11	342,266	2.0	%	6,509		1.7	%	3.4
AT&T Corporation	(6)	8	306,988	1.8	%	5,692		1.5	%	4.6
Ciena Corporation		4	229,848	1.3	%	4,200		1.1	%	3.6
The Boeing Company	(6)	4	143,480	0.8	%	4,199		1.1	%	2.9
BAE Systems PLC	(6)	7	212,339	1.2	%	3,164		0.8	%	4.0
Science Applications International Corp.	(6)	9	137,142	0.8	%	2,957		0.8	%	1.1
The Johns Hopkins Institutions	(6)	4	124,749	0.7	%	2,911		0.8	%	7.8
Merck & Co., Inc. (Unisys)	(6) (7)	2	227,273	1.3	%	2,747		0.7	%	3.5
Magellan Health Services, Inc.		2	113,727	0.7	%	2,673		0.7	%	2.8
AARP		1	104,695	0.6	%	2,571		0.7	%	13.2
Subtotal Top 20 Office Tenants		186	8,779,545	51.5	%	205,436		54.4	%	5.6
All remaining tenants		771	8,253,548	48.5	%	172,177		45.6	%	3.8
Total/Weighted Average		957	17,033,093	100.0	%	$	377,613	100.0	%	4.8

(1)	Table excludes owner occupied leasing activity which represents 150,373 square feet with a weighted average remaining lease term of 6.5 years as of September 30, 2008.
(2)	Total Annualized Rental Revenue is the monthly contractual base rent as of September 30, 2008, multiplied by 12, plus the estimated annualized expense reimbursements under existing office leases.
(3)	Order of tenants is based on Annualized Rent.
(4)	The weighting of the lease term was computed using Total Rental Revenue.
(5)	Many of our government leases are subject to early termination provisions which are customary to government leases.  The weighted average remaining lease term was computed assuming no exercise of such early termination rights.
(6)	Includes affiliated organizations or agencies.
(7)	Merck & Co., Inc. subleases 219,065 rentable square feet from Unisys’ 960,349 leased rentable square feet in our Greater Philadelphia region.

24

Combined Real Estate Revenue by Geographic Region by Quarter

(Dollars in thousands)

	2008									2007
	September 30			June 30			March 31			December 31			September 30
Office Properties:
Baltimore/Washington Corridor	$	46,139		$	46,426		$	45,577		$	43,101		$	43,850
Northern Virginia	19,523			18,927			19,004			18,421			18,554
Suburban Baltimore	13,912			13,502			13,910			14,464			13,576
Suburban Maryland	4,966			4,907			4,584			4,355			4,410
Colorado Springs	5,612			4,691			4,172			3,794			4,311
St. Mary’s and King George Counties	3,328			3,134			3,160			3,200			3,338
San Antonio	2,641			1,999			1,908			1,895			1,832
Greater Philadelphia	2,507			2,506			2,506			2,506			2,506
Central New Jersey	591			586			752			943			1,110
Other	2,775			2,257			2,577			2,749			1,704
Subtotal	101,994			98,935			98,150			95,428			95,191
Eliminations / other	(347		)	(739		)	(729		)	(312		)	(353		)
Combined Real Estate Revenue	$	101,647		$	98,196		$	97,421		$	95,116		$	94,838

Combined Net Operating Income by Geographic Region by Quarter

(Dollars in thousands)

	2008								2007
	September 30		June 30			March 31			December 31		September 30
Office Properties:
Baltimore/Washington Corridor	$	29,676	$	30,740		$	29,362		$	28,822	$	29,169
Northern Virginia	12,005		11,672			12,020			11,868		12,026
Suburban Baltimore	7,918		7,811			7,587			8,643		8,110
Suburban Maryland	2,968		3,320			2,920			2,743		2,664
Colorado Springs	3,753		2,953			2,590			2,337		2,339
St. Mary’s and King George Counties	2,471		2,387			2,418			2,440		2,554
San Antonio	1,945		1,556			1,475			1,438		1,457
Greater Philadelphia	2,464		2,466			2,442			2,477		2,471
Central New Jersey	533		548			543			653		433
Other	2,039		1,343			1,838			2,095		1,230
Subtotal	65,772		64,796			63,195			63,516		62,453
Eliminations / other	9		(568		)	(503		)	218		120
Combined NOI	$	65,781	$	64,228		$	62,692		$	63,734	$	62,573

25

Same Office Property Cash Net Operating Income by Quarter

(Dollars in thousands)

	2008									2007
	September 30			June 30			March 31			December 31			September 30
Office Properties: (1)
Baltimore/Washington Corridor	$	27,253		$	28,089		$	26,815		$	27,002		$	26,928
Northern Virginia	11,236			11,055			11,309			11,146			11,062
Suburban Baltimore	7,344			7,271			7,066			8,162			7,379
Suburban Maryland	2,852			2,754			2,679			2,529			2,486
Colorado Springs	2,128			2,069			2,326			2,065			1,832
St. Mary’s and King George Counties	2,400			2,352			2,360			2,394			2,463
San Antonio	1,194			1,179			1,136			1,171			1,128
Greater Philadelphia	2,739			2,688			2,665			2,697			2,692
Central New Jersey	525			535			547			566			451
Other	1,241			783			1,137			1,198			1,136
Total Office Properties	$	58,912		$	58,775		$	58,040		$	58,930		$	57,557
Less: Lease termination fees	(188		)	(54		)	(56		)	(688		)	(619		)
Same Office Cash NOI, adjusted for lease termination fees	$	58,724		$	58,721		$	57,984		$	58,242		$	56,938

Same Office Property GAAP Net Operating Income by Quarter

(Dollars in thousands)

	2008						2007
	September 30		June 30		March 31		December 31		September 30
Office Properties: (1)
Baltimore/Washington Corridor	$	27,849	$	28,945	$	27,721	$	27,918	$	27,880
Northern Virginia	11,811		11,418		11,794		11,635		11,835
Suburban Baltimore	7,964		7,779		7,530		8,519		7,888
Suburban Maryland	3,037		2,963		2,920		2,742		2,662
Colorado Springs	2,183		2,130		2,458		2,324		2,108
St. Mary’s and King George Counties	2,472		2,388		2,420		2,441		2,558
San Antonio	1,509		1,494		1,451		1,485		1,477
Greater Philadelphia	2,465		2,469		2,446		2,478		2,473
Central New Jersey	539		554		565		585		658
Other	1,465		898		1,345		1,406		1,340
Total Office Properties	$	61,294	$	61,038	$	60,650	$	61,533	$	60,879

(1) Same office properties represent buildings owned and 100% operational for a minimum of five reporting quarters. Amounts reported do not include the effects of eliminations.

26

Average Occupancy Rates by Region for Same Office Properties (1)

									St.Mary’s
	Baltimore /								and King
	Washington		Northern		Suburban		Suburban		George		Colorado		San		Greater		Central				Total
	Corridor		Virginia		Baltimore		Maryland		Counties		Springs		Antonio		Philadelphia		New Jersey		Other		Office
3rd Quarter 2008 Average
Number of Buildings	97		14		63		6		18		11		2		4		2		1		218
Rentable Square Feet	7,351,801		2,470,303		3,206,439		747,741		824,137		768,130		468,994		960,349		201,200		193,000		17,192,094
Percent Occupied	93.61	%	99.29	%	84.98	%	96.23	%	93.78	%	92.85	%	100.00	%	100.00	%	100.00	%	100.00	%	93.58	%
2nd Quarter 2008 Average
Number of Buildings	97		14		63		6		18		11		2		4		2		1		218
Rentable Square Feet	7,348,110		2,466,923		3,213,666		746,441		824,319		767,937		468,994		960,349		201,200		193,000		17,190,939
Percent Occupied	93.30	%	99.34	%	84.80	%	95.98	%	92.83	%	92.29	%	100.00	%	100.00	%	100.00	%	100.00	%	93.34	%
1st Quarter 2008 Average
Number of Buildings	97		14		63		6		18		11		2		4		2		1		218
Rentable Square Feet	7,348,258		2,466,428		3,205,354		746,441		824,683		767,937		468,994		960,349		201,200		193,000		17,182,644
Percent Occupied	92.49	%	99.34	%	83.94	%	96.18	%	92.42	%	96.10	%	100.00	%	100.00	%	100.00	%	100.00	%	92.99	%
4th Quarter 2007 Average
Number of Buildings	97		14		63		6		18		11		2		4		2		1		218
Rentable Square Feet	7,347,676		2,466,149		3,204,853		746,441		824,683		766,833		468,994		960,349		201,200		193,000		17,180,178
Percent Occupied	93.15	%	98.88	%	84.39	%	96.18	%	91.81	%	96.20	%	100.00	%	100.00	%	100.00	%	100.00	%	93.27	%
3rd Quarter 2007 Average
Number of Buildings	97		14		63		6		18		11		2		4		2		1		218
Rentable Square Feet	7,348,280		2,466,149		3,204,377		751,780		824,701		766,718		468,994		960,349		201,200		193,000		17,185,548
Percent Occupied	93.87	%	99.23	%	84.31	%	95.46	%	92.34	%	94.97	%	100.00	%	100.00	%	100.00	%	100.00	%	93.55	%

(1) Same office properties represent buildings owned and 100% operational for a minimum of five reporting quarters.

27

Office Lease Expiration Analysis by Year for Wholly Owned Properties

As of September 30, 2008 (1)

											Total
							Total Annualized		Percentage		Annual. Rental
		Square					Rental		of Total		Revenue of
Year and Region	Number	Footage	Percentage of		Percentage of		Revenue of		Annualized Rental		Expiring Leases
of Lease	of Leases	of Leases	Annual Occupied		Total Occupied		Expiring		Revenue		per Occupied
Expiration (2)	Expiring	Expiring	Square Feet		Square Feet		Leases (3)		Expiring		Square Foot
							(000’s)
Baltimore/Washington Corridor	16	149,535	47.4	%	0.9	%	4,115		1.1	%	27.52
Suburban Baltimore	21	139,119	44.1	%	0.8	%	2,719		0.7	%	19.55
St. Mary’s and King George Cos.	2	11,430	3.6	%	0.1	%	243		0.1	%	21.24
Colorado Springs	3	15,182	4.8	%	0.1	%	232		0.1	%	15.30
2008	42	315,266	100.0	%	1.9	%	7,310		1.9	%	23.19
Baltimore/Washington Corridor	81	1,283,857	44.8	%	7.5	%	25,256		6.7	%	19.67
Northern Virginia	20	207,072	7.2	%	1.2	%	5,455		1.4	%	26.34
Suburban Baltimore	55	384,693	13.4	%	2.3	%	7,490		2.0	%	19.47
Suburban Maryland	10	182,425	6.4	%	1.1	%	4,390		1.2	%	24.06
St. Mary’s and King George Cos.	13	163,100	5.7	%	1.0	%	2,535		0.7	%	15.55
Greater Philadelphia	2	467,284	16.3	%	2.7	%	5,763		1.5	%	12.33
Colorado Springs	10	176,710	6.2	%	1.0	%	3,675		1.0	%	20.80
Other	1	1,466	0.1	%	0.0	%	23		0.0	%	16.00
2009	192	2,866,607	100.0	%	16.8	%	54,588		14.5	%	19.04
Baltimore/Washington Corridor	65	992,400	42.2	%	5.8	%	23,652		6.3	%	23.83
Northern Virginia	20	568,026	24.2	%	3.3	%	15,431		4.1	%	27.17
Suburban Baltimore	54	229,605	9.8	%	1.3	%	5,220		1.4	%	22.74
Suburban Maryland	3	172,803	7.3	%	1.0	%	3,221		0.9	%	18.64
St. Mary’s and King George Cos.	12	168,042	7.1	%	1.0	%	2,698		0.7	%	16.06
Greater Philadelphia	1	160,000	6.8	%	0.9	%	1,630		0.4	%	10.19
Colorado Springs	6	55,350	2.4	%	0.3	%	1,133		0.3	%	20.48
Other	1	4,904	0.2	%	0.0	%	78		0.0	%	16.00
2010	162	2,351,130	100.0	%	13.8	%	53,064		14.1	%	22.57
Baltimore/Washington Corridor	48	838,345	48.8	%	4.9	%	17,733		4.7	%	21.15
Northern Virginia	10	89,964	5.2	%	0.5	%	2,687		0.7	%	29.87
Suburban Baltimore	71	484,025	28.2	%	2.8	%	9,908		2.6	%	20.47
Suburban Maryland	8	51,605	3.0	%	0.3	%	1,463		0.4	%	28.35
St. Mary’s and King George Cos.	5	36,456	2.1	%	0.2	%	726		0.2	%	19.92
Colorado Springs	11	216,464	12.6	%	1.3	%	3,861		1.0	%	17.84
2011	153	1,716,859	100.0	%	10.1	%	36,378		9.6	%	21.19
Baltimore/Washington Corridor	39	1,160,569	45.4	%	6.8	%	29,326		7.8	%	25.27
Northern Virginia	11	119,789	4.7	%	0.7	%	3,556		0.9	%	29.69
Suburban Baltimore	49	661,358	25.9	%	3.9	%	12,098		3.2	%	18.29
Suburban Maryland	3	38,310	1.5	%	0.2	%	948		0.3	%	24.75
St. Mary’s and King George Cos.	8	201,788	7.9	%	1.2	%	3,538		0.9	%	17.53
Greater Philadelphia	1	219,065	8.6	%	1.3	%	2,565		0.7	%	11.71
Colorado Springs	8	76,488	3.0	%	0.4	%	1,628		0.4	%	21.28
San Antonio	2	78,359	3.1	%	0.5	%	930		0.2	%	11.86
2012	121	2,555,726	100.0	%	15.0	%	54,590		14.5	%	21.36
Baltimore/Washington Corridor	46	977,269	56.5	%	5.7	%	26,517		7.0	%	27.13
Northern Virginia	8	138,753	8.0	%	0.8	%	3,949		1.0	%	28.46
Suburban Baltimore	32	384,646	22.2	%	2.3	%	6,898		1.8	%	17.93
Suburban Maryland	2	7,066	0.4	%	0.0	%	196		0.1	%	27.81
St. Mary’s and King George Cos.	6	99,094	5.7	%	0.6	%	1,529		0.4	%	15.43
Colorado Springs	5	120,982	7.0	%	0.7	%	2,453		0.6	%	20.28
Other	1	3,014	0.2	%	0.0	%	—		0.0	%	0.00
2013	100	1,730,824	100.0	%	10.2	%	41,542		11.0	%	24.00
Baltimore/Washington Corridor	66	1,788,916	32.9	%	10.5	%	46,916		12.4	%	26.23
Northern Virginia	23	1,325,442	24.4	%	7.8	%	39,890		10.6	%	30.10
Suburban Baltimore	41	408,996	7.5	%	2.4	%	7,541		2.0	%	18.44
Suburban Maryland	9	222,696	4.1	%	1.3	%	5,095		1.3	%	22.88
St. Mary’s and King George Cos.	3	87,083	1.6	%	0.5	%	1,660		0.4	%	19.07
Greater Philadelphia	1	114,000	2.1	%	0.7	%	1,162		0.3	%	10.19
Colorado Springs	11	467,192	8.6	%	2.7	%	8,892		2.4	%	19.03
San Antonio	4	522,284	9.6	%	3.1	%	7,347		1.9	%	14.07
Central New Jersey	2	201,200	3.7	%	1.2	%	2,340		0.6	%	11.63
Other	2	295,842	5.4	%	1.7	%	8,327		2.2	%	28.15
Thereafter	162	5,433,651	100.0	%	31.9	%	129,171		34.2	%	23.77
Other (4)	25	63,030	100.0	%	0.4	%	970		0.3	%	15.39
Total / Average	957	17,033,093			100.0	%	$	377,613	100.0	%	$	22.17

NOTE: As of September 30, 2008, the weighted average lease term for the wholly owned properties is 4.8 years.

(1) This expiration analysis includes the effect of early renewals completed on existing leases but excludes the effect of new tenant leases on 206,277 square feet yet to commence as of September 30, 2008.

(2) Many of our government leases are subject to certain early termination provisions which are customary to government leases. The year of lease expiration was computed assuming no exercise of such early termination rights.

(3) Total Annualized Rental Revenue is the monthly contractual base rent as of September 30, 2008 multiplied by 12 plus the estimated annualized expense reimbursements under existing office leases.

(4) Other consists primarily of amenities, including cafeterias, concierge offices and property management space. In addition, month-to-month leases and leases which have expired but the tenant remains in holdover are included in this line as the exact expiration date is unknown.

28

Quarterly and Year to Date Office Renewal Analysis for Wholly Owned Properties as of September 30, 2008

	Baltimore/ Washington Corridor			Northern Virginia			Suburban Baltimore			Suburban Maryland			St. Mary’s and King George Counties			Colorado Springs			Greater Philadelphia			Total Office
Quarter Ended September 30, 2008:
Expiring Square Feet	437,418			8,154			145,077			2,198			100,740			41,507			333,065			1,068,159
Vacated Square Feet	88,005			3,541			119,354			—			3,552			3,379			—			217,831
Renewed Square Feet	349,413			4,613			25,723			2,198			97,188			38,128			333,065			850,328
Retention Rate (% based upon square feet)	79.88		%	56.57		%	17.73		%	100.00		%	96.47		%	91.86		%	100.00		%	79.61		%
Renewed Space Only:
Average Committed Cost per Square Foot	$	6.32		$	0.99		$	8.83		$	0.52		$	—		$	0.35		$	13.67		$	8.24
Weighted Average Lease Term in years	4.5			1.0			3.6			1.0			2.0			1.5			5.6			4.5
Change in Total Rent - GAAP	30.97		%	37.35		%	1.31		%	-28.87		%	6.09		%	1.96		%	34.20		%	26.67		%
Change in Total Rent - Cash	22.33		%	20.76		%	-4.03		%	-26.55		%	3.00		%	0.00		%	1.36		%	13.05		%
Renewed & Retenanted Space:
Average Committed Cost per Square Foot	$	6.56		$	38.65		$	28.08		$	0.52		$	1.30		$	0.34		$	13.67		$	10.14
Weighted Average Lease Term in years	4.5			5.2			6.3			1.0			2.3			1.5			5.6			4.7
Change in Total Rent - GAAP	27.93		%	19.33		%	1.53		%	-28.87		%	5.37		%	1.89		%	34.20		%	23.09		%
Change in Total Rent - Cash	18.60		%	9.94		%	-7.15		%	-26.55		%	1.73		%	-0.01		%	1.36		%	9.78		%
Nine Months Ended September 30, 2008:
Expiring Square Feet	831,091			64,151			475,187			7,890			241,347			142,120			333,065			2,094,851
Vacated Square Feet	159,264			14,659			228,872			3,021			11,395			46,083			—			463,294
Renewed Square Feet	671,827			49,492			246,315			4,869			229,952			96,037			333,065			1,631,557
Retention Rate (% based upon square feet)	80.84		%	77.15		%	51.84		%	61.71		%	95.28		%	67.57		%	100.00		%	77.88		%
Renewed Space Only:
Average Committed Cost per Square Foot	$	6.84		$	3.12		$	3.05		$	7.97		$	1.91		$	0.58		$	13.67		$	6.49
Weighted Average Lease Term in years	4.3			2.0			1.9			2.1			3.1			2.5			5.6			3.8
Change in Total Rent - GAAP	21.36		%	13.83		%	2.08		%	-15.94		%	10.35		%	18.55		%	34.20		%	18.24		%
Change in Total Rent - Cash	12.96		%	4.56		%	-0.23		%	-18.32		%	5.73		%	14.29		%	1.36		%	8.48		%
Renewed & Retenanted Space:
Average Committed Cost per Square Foot	$	9.51		$	8.41		$	9.93		$	9.05		$	2.45		$	1.65		$	13.67		$	8.92
Weighted Average Lease Term in years	4.7			2.5			3.0			2.7			3.2			2.8			5.6			4.2
Change in Total Rent - GAAP	16.85		%	9.11		%	0.28		%	-11.09		%	9.54		%	16.71		%	34.20		%	14.46		%
Change in Total Rent - Cash	8.56		%	1.60		%	-3.25		%	-14.57		%	4.80		%	12.51		%	1.36		%	5.29		%

Notes:	No renewal or retenanting activity transpired in our San Antonio, Central New Jersey or Other regions.
	Activity is exclusive of owner occupied space and leases with less than a one-year term.
	Expiring square feet includes early renewals and early terminations.

29

Year to Date Wholly Owned Acquisition Summary as of September 30, 2008 (1)

(Dollars in thousands)

	Submarket	Acquisition Date	Building Count	Square Feet as of 9/30/08	Occupancy Percentage at Acquisition		Contractual Purchase Price		Investment (2)
3535 Northrop Grumman Point	Colorado Springs East	6/10/2008	1	124,305	100.0	%	$	23,235	$	23,240
1560 Cable Ranch Road (Buildings A and B)	San Antonio Northwest	6/19/2008	2	122,975	100.0	%	17,300		17,317
Total			3	247,280			$	40,535	$	40,557

(1) Includes operational buildings only.

(2) Initial accounting investment recorded by property.

Year to Date Wholly Owned Disposition Summary as of September 30, 2008 (1)

(Dollars in thousands)

	Submarket	Disposition Date	Building Count	Square Feet	Contractual Sales Price
429 Ridge Road	Exit 8A — Cranbury	1/31/2008	1	142,385	$	17,000
47 Commerce Drive	Exit 8A — Cranbury	4/1/2008	1	41,398	3,150
7253 Ambassador Road	Baltimore County Westside	6/2/2008	1	38,930	5,100
Total			3	222,713	$	25,250

(1) Includes operational buildings only.

30

Development Summary as of September 30, 2008

(Dollars in thousands)

			Wholly												Actual or
			Owned		Total										Anticipated
			or Joint		Rentable				Anticipated				Outstanding		Construction	Anticipated
			Venture	Demand	Square		Percentage		Total		Cost		Loan as of		Completion	Operational
Property and Location		Submarket	(JV)	Driver	Feet		Leased		Cost (1)		to date		9/30/2008		Date (2)	Date (3)
Under Construction
7700 Potranco Road, Building C San Antonio, Texas		San Antonio  Northwest	Owned	Government	38,255		100	%	$	4,486	$	4,481	$	—	4Q 08	4Q 08
7700 Potranco Road, Building HI San Antonio, Texas		San Antonio Northwest	Owned	Government	52,352		100	%	3,605		3,395		—		4Q 08	4Q 08
5850 University Research Court College Park, Maryland		College Park	JV	Government	123,464		100	%	23,510		1,528		—		4Q 09	1Q 10
Subtotal Government					214,071		100	%	$	31,601	$	9,404	$	—
% of Total Drivers					17	%
6721 Columbia Gateway Drive Columbia, Maryland		Howard Co. Perimeter	Owned	Defense Information Technology	131,451		100	%	$	34,490	$	23,829	$	18,168	4Q 08	2Q 09
10807 New Allegiance Drive (Epic One) Colorado Springs, Colorado		I-25 North Corridor	Owned	Defense Information Technology	145,723		23	%	30,870		14,590		—		2Q 09	2Q 10
300 Sentinel Drive (300 NBP) Annapolis Junction, Maryland		BWI Airport	Owned	Defense Information Technology	185,719		0	%	49,471		20,674		—		2Q 09	2Q 10
565 Space Center Drive (Patriot Park 7) Colorado Springs, Colorado		Colorado Springs East	Owned	Defense Information Technology	89,773		0	%	18,000		8,473		—		2Q 09	2Q 10
Subtotal Defense Information Technology					552,666		30	%	$	132,831	$	67,566	$	18,168
% of Total Drivers					44	%
7740 Milestone Parkway Hanover, Maryland		BWI Airport	JV	Market Demand	148,130		0	%	$	36,493	$	27,112	$	—	3Q 08	3Q 09
9945 Federal Drive (Hybrid I) Colorado Springs, Colorado		I-25 North Corridor	Owned	Market Demand	73,940		0	%	12,595		8,219		5,567		3Q 08	3Q 09
9925 Federal Drive (Hybrid II) Colorado Springs, Colorado	(4)	I-25 North Corridor	Owned	Market Demand	53,745		81	%	8,498		7,883		5,643		3Q 08	3Q 09
Subtotal Market Demand					275,815		16	%	$	57,586	$	43,215	$	11,210
% of Total Drivers					22	%
5825 University Research Court College Park, Maryland	(5)	College Park	JV	Research Park	116,083		53	%	$	21,845	$	17,665	$	—	1Q 08	1Q 09
5520 Research Park Drive (UMBC) Baltimore, Maryland		BWI Airport	Land Lease	Research Park	105,964		26	%	21,960		15,273		12,153		3Q 08	3Q 09
Subtotal Research Park					222,047		40	%	$	43,805	$	32,937	$	12,153
% of Total Drivers					18	%
Total Under Construction					1,264,599		41	%	$	265,823	$	153,122	$	41,532
					100	%

	% of Total		Total Rentable	Percentage
Regions	Regions		Square Feet	Leased
Baltimore/Washington Corridor	45	%	571,264	28	%
Colorado Springs	29	%	363,181	21	%
San Antonio	7	%	90,607	100	%
Suburban Maryland	19	%	239,547	77	%
Total Under Construction by Region	100	%	1,264,599	41	%

(1)	Anticipated Total Cost includes land, construction and leasing costs.
(2)	Actual or anticipated construction completion date is the estimated date of completion of the building shell.
(3)	Anticipated operational date is the estimated date when leases have commenced on 100% of a property’s space or one year from the cessation of major construction activities.
(4)	Although classified as “Under Construction,” 43,721 square feet are operational.
(5)	Although classified as “Under Construction,” 41,500 square feet are operational.

Demand Driver Categories (as classified by COPT management):

Defense Information Technology: Development opportunity created through our current and future relationships with defense information technology contractors and, possibly, minor Government tenancy.

Government: Development opportunity created through our existing and future relationship with various agencies of the government of the United States of America. Excludes Government tenancy included in Defense Information Technology.

Market Demand: Development opportunity created through perceived unfulfilled space requirements within a specific submarket; potential submarket demand exceeds existing supply.

Research Park: Development opportunity created through specific research park relationship.

31

Development Summary as of September 30, 2008 (continued)

(Dollars in thousands)

		Wholly												Actual or
		Owned		Total										Anticipated
		or Joint		Rentable				Anticipated				Outstanding		Construction	Anticipated
		Venture	Demand	Square		Percentage		Total		Cost		Loan as of		Completion	Operational
Property and Location	Submarket	(JV)	Driver	Feet		Leased		Cost (1)		to date		9/30/2008		Date (2)	Date (3)
Redevelopment
2900 Towerview Road Herndon, Virginia (4)	Route 28 South	JV	N/A	137,037		57	%	$	18,408	$	16,933	$	—	4Q 07	4Q 08
Subtotal Northern Virginia				137,037		57	%	$	18,408	$	16,933	$	—
7468 Candlewood Road Hanover, Maryland	BWI Airport	JV	N/A	356,000		0	%	$	38,307	$	26,762	$	—	3Q 09	3Q 10
Subtotal Baltimore/Washington Corridor				356,000		0	%	$	38,307	$	26,762	$	—
Total Redevelopment				493,037		16	%	$	56,715	$	43,695	$	—
Under Development
Riverwood I & II Columbia, Maryland	Howard Co. Perimeter	Owned	Government	70,000				$	15,200	$	2,287	$	—	2Q 10	3Q 10
324 Sentinel Drive (324 NBP) Annapolis Junction, Maryland	BWI Airport	Owned	Government	121,250				30,000		2,296		—		4Q 09	3Q 10
8000 Potranco Road San Antonio, Texas	San Antonio Northwest	Owned	Government	125,000				22,500		1,909		—		3Q 10	3Q 11
8030 Potranco Road San Antonio, Texas	San Antonio Northwest	Owned	Government	125,000				22,500		1,977		—		3Q 10	3Q 11
Subtotal Government				441,250				$	90,200	$	8,469	$	—
% of Total Drivers				45	%
308 Sentinel Way (308 NBP) Annapolis Junction, Maryland	BWI Airport	Owned	Defense Information Technology	161,200				$	38,000	$	3,080	$	—	1Q 10	4Q 10
110 Thomas Johnson Drive, Bldg #2 Frederick, Maryland	Frederick	Owned	Defense Information Technology	85,000				16,000		1,933		—		2Q 10	2Q 11
Northgate Business Park (Lot A) Aberdeen, Maryland	Harford County	Owned	Defense Information Technology	80,000				16,500		1,337		—		4Q 09	4Q 10
Northgate Business Park (Lot C) Aberdeen, Maryland	Harford County	Owned	Defense Information Technology	85,000				16,600		1,367		—		2Q 10	2Q 11
Subtotal Defense Information Technology				411,200				$	87,100	$	7,717	$	—
% of Total Drivers				42	%
8130 Corporate Drive White Marsh, Maryland	White Marsh	Owned	Market Demand	125,000				$	26,500	$	4,213	$	—	1Q 10	1Q 11
Subtotal Market Demand				125,000				$	26,500	$	4,213	$	—
% of Total Drivers				13	%
Total Under Development				977,450				$	203,800	$	20,399	$	—
				100	%

	% of Total		Total Rentable
Regions	Regions		Square Feet
Baltimore/Washington Corridor	36	%	352,450
San Antonio	26	%	250,000
Suburban Maryland	9	%	85,000
Suburban Baltimore	30	%	290,000
Total Under Development by Region	100	%	977,450

(1)	Anticipated Total Cost includes land, construction and leasing costs.
(2)	Actual or anticipated construction completion date is the estimated date of completion of the building shell.
(3)	Anticipated operational date is the estimated date when leases have commenced on 100% of a property’s space or one year from the cessation of major construction activities.
(4)	Although classified as “Redevelopment,” 78,171 square feet are operational.

Demand Driver Categories (as classified by COPT management):

Defense Information Technology: Development opportunity created through our current and future relationships with defense information technology contractors and, possibly, minor Government tenancy.

Government: Development opportunity created through our existing and future relationship with various agencies of the government of the United States of America. Excludes Government tenancy included in Defense Information Technology.

Market Demand: Development opportunity created through perceived unfulfilled space requirements within a specific submarket; potential submarket demand exceeds existing supply.

Research Park: Development opportunity created through a specific research park relationship.

32

Total Development Placed into Service as of September 30, 2008

(Dollars in thousands)

									Percentage of
									Development Square
		Wholly Owned	Total	Development Square Feet Placed Into Service					Feet Placed Into
		or Joint Venture	Rentable	Year 2007	Year 2008				Service Leased
Property and Location	Submarket	(JV)	Square Feet		1st Quarter	2nd Quarter	3rd Quarter		as of 9/30/08
302 Sentinel Drive (302 NBP) Annapolis Junction, Maryland	BWI Airport	Owned	155,731	48,377	107,354	—	—	(1)	79	%
9965 Federal Drive Colorado Springs, Colorado	I-25 North Corridor	Owned	74,749	41,120	33,629	—	—	(2)	100	%
1055 North Newport Road Colorado Springs, Colorado	Colorado Springs East	Owned	59,763	—	59,763	—	—		100	%
1362 Mellon Road Hanover, Maryland	BWI Airport	Owned	44,134	—	—	44,134	—		0	%
5825 University Research Court College Park, Maryland	College Park	JV	116,083	—	—	41,500	—		100	%
655 Space Center Drive (Patriot Park 6) Colorado Springs, Colorado	Colorado Springs East	Owned	103,970	—	—	103,970	—		100	%
9925 Federal Drive Colorado Springs, Colorado	I–25 North Corridor	Owned	53,745	—	—	—	43,721		100	%
Total Development Placed Into Service			608,175	89,497	200,746	189,604	43,721		85	%

(1) In March 2008, 100% of this building became operational. As of December 31, 2007, 48,377 square feet were placed into service.

(2) In March 2008, 100% of this building became operational. As of December 31, 2007, 41,120 square feet were placed into service.

33

Land Inventory as of September 30, 2008

				Non-Wholly Owned			Wholly Owned
Location		Submarket	Status	Acres		Developable Square Feet	Acres	Developable Square Feet
Westfields Corporate Center		Dulles South	owned	—		—	19	246,773
Westfields Corporate Center		Dulles South	owned	—		—	17	377,297
Westfields Corporate Center		Dulles South	owned	—		—	32	674,163
Woodland Park		Herndon	owned	—		—	5	225,000
Total Northern Virginia				—		—	73	1,523,233
National Business Park (Phase II)		BWI Airport	owned	—		—	26	569,462
National Business Park (Phase III)		BWI Airport	owned	—		—	194	1,128,750
1243 Winterson Road (AS 22)		BWI Airport	owned	—		—	2	30,000
940 Elkridge Landing Road (AS 7)		BWI Airport	owned	—		—	3	53,941
Arundel Preserve		BWI Airport	under contract/JV	56	up to	1,651,870	—	—
1460 Dorsey Road		BWI Airport	owned	—		—	6	60,000
Columbia Gateway Parcel T-11		Howard Co. Perimeter	owned	—		—	14	220,000
7125 Columbia Gateway Drive		Howard Co. Perimeter	owned	—		—	5	120,000
Total Baltimore / Washington Corridor				56		1,651,870	251	2,182,153
White Marsh		White Marsh	owned	—		—	145	1,567,000
37 Allegheny Avenue		Towson	owned	—		—	0.3	40,000
Northgate Business Park		Harford County	owned	—		—	45	635,000
Total Suburban Baltimore				—		—	190	2,242,000
110 Thomas Johnson Drive		Frederick	owned	—		—	3	85,000
Route 15 / Biggs Ford Road		Frederick	owned	—		—	107	1,000,000
Rockville Corporate Center		Rockville	owned	—		—	10	220,000
M Square Research Park		College Park	JV - 45% ownership	49		510,453	—	—
Total Suburban Maryland				49		510,453	120	1,305,000
Unisys Campus		Blue Bell	owned	—		—	45	600,000
Total Greater Philadelphia				—		—	45	600,000
Princeton Technology Center		Exit 8A - Cranbury	owned	—		—	19	250,000
Total Central New Jersey				—		—	19	250,000
Dahlgren Technology Center		King George County	owned	—		—	39	122,000
Expedition Park		St. Mary’s County	owned	—		—	6	60,000
Total St. Mary’s & King George Counties				—		—	46	182,000
InterQuest		I - 25 North Corridor	owned	—		—	113	1,626,592
9965 Federal Drive		I - 25 North Corridor	owned	—		—	4	30,000
Patriot Park		Colorado Springs East	owned	—		—	71	756,257
Aerotech Commerce		Colorado Springs East	owned	—		—	6	90,000
Total Colorado Springs				—		—	194	2,502,849
San Antonio		San Antonio Northwest	owned	—		—	9	125,000
San Antonio		San Antonio Northwest	owned	—		—	31	375,000
Santikos		San Antonio Northwest	owned	—		—	31	500,000
Total San Antonio				—		—	71	1,000,000
Indian Head		Charles County, MD	JV - 75% ownership	169		827,250	—	—
Fort Ritchie	(1)	Fort Ritchie	owned	—		—	591	1,700,000
Total Other				169		827,250	591	1,700,000
TOTAL				274		2,989,573	1,598	13,487,235

This land inventory schedule excludes all properties listed as under construction, redevelopment or under development as detailed on pages 31 and 32.

(1) The Fort Ritchie acquisition includes 284,429 square feet of existing office space targeted for future redevelopment and 110 existing usable residential units.

34

Joint Venture Summary as of September 30, 2008

(Dollars in thousands)

Consolidated Properties

		Joint Venture										Option to
		Interest							Consolidated			Acquire
		Held By			Square		Total		Debt as		Recourse	Partner’s
Property and Location		COPT		Status	Feet	Acreage	Assets (1)		of 9/30/08		to COPT	Interest
4230 Forbes Boulevard Lanham, Maryland		50.0	%	Operating	55,866	5 acres	$	4,472	$	—	N/A	Yes
7468 Candlewood Road Hanover, Maryland	(2)	92.5	%	Redevelopment	356,000	19 acres	26,867		—		N/A	Yes
2900 Towerview Road Herndon, Virginia		92.5	%	Operating/ Redevelopment	137,037	8 acres	16,870		—		N/A	Yes
13849 Park Center Road Herndon, Virginia		92.5	%	Redevelopment	4,265	.1 acre	563		—		N/A	Yes
Indian Head Technology Center Business Park Indian Head, Maryland		75.0	%	Land Inventory	827,250	169 acres	4,959		—		N/A	No
7740-7744 Milestone Parkway Hanover, Maryland	(3)	50.0	%	Construction/ Land Inventory	455,400	23 acres	27,126		—		N/A	No
5825 University Research Court College Park, Maryland		45.0	%	Construction	116,083	8 acres	19,552		—		N/A	No
5850 University Research Court College Park, Maryland		45.0	%	Construction	123,464	8 acres	3,284		—		N/A	No
M Square Research Park College Park, Maryland		45.0	%	Land Inventory	510,453	49 acres	2,559		—		N/A	No
TOTAL							$	106,252	$	—

Unconsolidated Properties

	Joint Venture										Option to
	Interest							Off-Balance			Acquire
	Held By			Square	COPT			Sheet Debt as		Recourse	Partner’s
Property and Location	COPT		Status	Feet	Investment			of 9/30/08		to COPT	Interest
Greater Harrisburg Portfolio Harrisburg and Mechanicsburg, Pennsylvania	20.0	%	Operating	671,759	$	(4,668	)	$	66,600	No	No

(1)  Total assets includes any outside investment basis related to the applicable joint venture plus the total assets recorded on the books of the consolidated joint venture.

(2)  The 7468 Candlewood Road project is currently being redeveloped into approximately 356,000 rentable square feet of warehouse/flex space.

(3)  In this joint venture entity, one building totaling 151,800 square feet is currently under construction.

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Reconciliations of Non GAAP Measurements

(Dollars in thousands)

	2008									2007
	September 30			June 30			March 31			December 31			September 30
Total Assets or Denominator for Debt to Total Assets	$	3,099,728		$	3,010,470		$	2,936,744		$	2,931,853		$	2,916,023
Accumulated depreciation	339,429			320,879			303,709			288,747			270,899
Intangible assets on real estate acquisitions, net	98,282			104,136			102,647			108,661			116,368
Assets other than assets included in investment in real estate	(356,152		)	(309,303		)	(319,680		)	(327,914		)	(330,590		)
Denominator for Debt to Undepreciated Book Value of Real Estate Assets	$	3,181,287		$	3,126,182		$	3,023,420		$	3,001,347		$	2,972,700
GAAP revenues from real estate operations	$	101,644		$	98,111		$	97,151		$	94,567		$	94,102
Revenues from discontinued operations	3			85			270			549			736
Combined real estate revenues	$	101,647		$	98,196		$	97,421		$	95,116		$	94,838
GAAP revenues from real estate operations	$	101,644		$	98,111		$	97,151		$	94,567		$	94,102
Property operating expenses	(35,854		)	(33,957		)	(34,542		)	(31,090		)	(31,577		)
Revenues from discontinued operations	3			85			270			549			736
Property operating expenses from discontinued operations	(12		)	(11		)	(187		)	(292		)	(688		)
Combined net operating income	$	65,781		$	64,228		$	62,692		$	63,734		$	62,573
GAAP net operating income for same office properties	$	61,294		$	61,038		$	60,650		$	61,533		$	60,879
Less: Straight-line rent adjustments	(2,001		)	(1,903		)	(2,242		)	(2,265		)	(2,816		)
Less: Amortization of deferred market rental revenue	(381		)	(360		)	(368		)	(338		)	(506		)
Cash net operating income for same office properties	$	58,912		$	58,775		$	58,040		$	58,930		$	57,557
Less: Lease termination fees, gross	(188		)	(54		)	(56		)	(688		)	(619		)
Cash net operating income for same office properties, adjusted for lease termination fees	$	58,724		$	58,721		$	57,984		$	58,242		$	56,938
Depreciation and amortization	$	25,583		$	24,955		$	24,892		$	25,889		$	26,025
Depreciation and amortization from discontinued operations	—			—			52			718			241
Combined real estate related depreciation and other amortization	$	25,583		$	24,955		$	24,944		$	26,607		$	26,266
Total tenant improvements and incentives on operating properties	$	6,305		$	4,731		$	3,847		$	2,692		$	4,605
Total capital improvements on operating properties	3,179			2,631			1,017			4,748			2,514
Total leasing costs for operating properties	999			520			1,245			1,850			719
Less: Nonrecurring tenant improvements and incentives on operating properties	(1,995		)	(1,287		)	(795		)	(811		)	(1,887		)
Less: Nonrecurring capital improvements on operating properties	(1,299		)	(866		)	(502		)	(1,442		)	(1,198		)
Less: Nonrecurring leasing costs for operating properties	(217		)	(22		)	(30		)	(575		)	(89		)
Add: Recurring improvements on operating properties held through joint ventures	36			114			—			42			—
Recurring capital expenditures	$	7,008		$	5,821		$	4,782		$	6,504		$	4,664
Interest expense from continuing operations	$	20,506		$	19,437		$	20,309		$	20,719		$	20,968
Interest expense from discontinued operations	—			10			41			80			177
Combined interest expense or denominator for interest coverage	$	20,506		$	19,447		$	20,350		$	20,799		$	21,145
Scheduled principal amortization	3,424			3,566			3,820			4,611			3,936
Denominator for Debt Service Coverage	$	23,930		$	23,013		$	24,170		$	25,410		$	25,081
Scheduled principal amortization	(3,424		)	(3,566		)	(3,820		)	(4,611		)	(3,936		)
Preferred dividends - redeemable non-convertible	4,025			4,026			4,025			4,025			4,025
Preferred distributions	165			165			165			165			165
Denominator for Fixed Charge Coverage	$	24,696		$	23,638		$	24,540		$	24,989		$	25,335
Common dividends for Earnings Payout Ratio	$	19,183		$	16,197		$	16,173		$	16,097		$	16,092
Common distributions	3,021			2,772			2,771			2,777			2,777
Dividends and distributions for FFO and AFFO Payout Ratio	$	22,204		$	18,969		$	18,944		$	18,874		$	18,869
Income tax expense from continuing operations	$	97		$	(107	)	$	112		$	89		$	197
Income tax expense from gain on sales of discontinued operations	—			—			—			44			—
Income tax expense from gain on other sales of real estate	—			5			573			1,068			—
Combined income tax expense	$	97		$	(102	)	$	685		$	1,201		$	197

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