CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

COMPANY PROFILE

The Company:

CommonWealth REIT, or CWH, is a real estate investment trust, or REIT, which primarily owns office and industrial buildings located throughout the United States. The majority of our properties are office buildings located in suburban areas and central business districts, or CBDs, of major metropolitan markets. As of September 30, 2010, we also owned 31.5 million square feet of industrial and other space, including 17.9 million square feet of leased industrial and commercial lands in Oahu, Hawaii. In October, we acquired 1.4 million square feet of industrial properties in Australia. In the future, we may expand our investments in that country. We have been investment grade rated since 1994 and we are included in a number of financial indices, including the Russell 1000®, the MSCI US REIT Index, the S&P REIT Composite Index and the FTSE NAREIT Composite Index.

Strategy:

Our primary business strategy is to efficiently operate our properties to maintain high occupancies, at market rents, with strong credit quality tenants. We attempt to maintain an investment portfolio that is balanced between “security” and “growth”. The security part of our portfolio includes properties that are long term leased or leased to tenants we believe are likely to renew their occupancy, such as our leased lands in Hawaii. The growth part of our portfolio includes our multi-tenant office buildings, which we believe may generate higher rents and appreciate in value in the future because of their physical qualities and locations. Although we sometimes sell properties, we generally consider ourselves to be a long term investor and we are more interested in the long term earnings potential of our properties than selling properties for short term gains. We currently do not have any investments in off balance sheet entities.

Management:

CWH is managed by Reit Management & Research LLC, or RMR. RMR is a real estate management company which was founded in 1986 to manage public investments in real estate. As of September 30, 2010, RMR managed one of the largest portfolios of publicly owned real estate in North America, including 1,380 properties, located in 46 states, Washington, DC, Puerto Rico and Ontario, Canada. RMR has over 620 employees in its headquarters and regional offices located throughout the U.S. In addition to managing CWH, RMR also manages Hospitality Properties Trust, or HPT, a publicly traded REIT that owns hotels and travel centers, Senior Housing Properties Trust, or SNH, a publicly traded REIT that primarily owns healthcare properties, and Government Properties Income Trust, or GOV, a publicly traded REIT that owns buildings majority leased to government tenants located throughout the U.S. RMR also provides management services to Five Star Quality Care, Inc., a healthcare services company which is a tenant of SNH, and to TravelCenters of America LLC, an operator of travel centers which is a tenant of HPT. An affiliate of RMR, RMR Advisors, Inc., is the investment manager of mutual funds which principally invests in securities of unaffiliated real estate companies. The public companies managed by RMR and its affiliates had combined total gross assets of approximately $17.6 billion as of September 30, 2010. We believe that being managed by RMR is a competitive advantage for CWH because RMR provides us with a depth and quality of management and experience which may be unequaled in the real estate industry. We also believe RMR provides management services to CWH at costs that are lower than we would have to pay for similar quality services.

Corporate Headquarters:

400 Centre Street

Newton, MA 02458

(t) (617) 332-3990

(f) (617) 332-2261

Stock Exchange Listing:

New York Stock Exchange

NYSE Trading Symbols:

Common Stock — CWH

Preferred Stock Series C — CWH-PC

Preferred Stock Series D — CWH-PD

7.50% Senior Notes due 2019 — CWHN

Senior Unsecured Debt Ratings:

Moody’s — Baa2

Standard & Poor’s — BBB

Portfolio Data (as of 9/30/10) (1):

Total properties	519
Total sq. ft. (000s)	66,506
Percent leased	86.4	%

Portfolio Concentration by Property Type (1)(2):

	9/30/10		Q3 2010
	Sq. Ft.		NOI
Suburban Office	33.3	%	42.7	%
CBD Office	19.3	%	34.6	%
Industrial & Other	47.4	%	22.7	%
Total	100.0	%	100.0	%

Portfolio Concentration by Major Market (1)(2):

	9/30/10		Q3 2010
	Sq. Ft.		NOI
Metro Philadelphia, PA	8.0	%	12.3	%
Oahu, HI	27.0	%	10.9	%
Metro Denver, CO	3.0	%	5.9	%
Metro Washington, DC	2.2	%	5.7	%
Metro Boston, MA	3.6	%	4.9	%
Other markets	56.2	%	60.3	%
Total	100.0	%	100.0	%

(1) Excludes properties classified in discontinued operations.

(2) We compute property net operating income, or NOI, as rental income from real estate less property operating expenses; see Exhibit A for the calculation of NOI and a reconciliation of NOI to Net Income.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

KEY FINANCIAL DATA (1)

(amounts in thousands, except per share data)

	As of and For the Three Months Ended
	9/30/2010			6/30/2010			3/31/2010			12/31/2009			9/30/2009

Shares Outstanding:
Common shares outstanding (at end of period)	72,139			64,596			64,590			55,965			55,965
Common shares outstanding (at end of period) – diluted (2)	79,437			71,894			71,888			63,263			63,263
Preferred shares outstanding (at end of period) (2)	28,180			28,180			28,180			28,180			28,180
Weighted average common shares and units outstanding – basic	65,173			64,595			56,732			55,965			55,933
Weighted average common shares and units outstanding – diluted (2)	72,471			71,893			64,030			63,263			63,231

Common Share Data:
Price at end of period	$	25.60		$	24.84		$	31.12		$	25.88		$	30.08
High during period	$	28.00		$	33.00		$	32.56		$	30.20		$	32.52
Low during period	$	22.89		$	24.60		$	25.24		$	24.16		$	15.80
Annualized dividends paid per share (3)	$	2.00		$	1.92		$	1.92		$	1.92		$	1.92
Annualized dividend yield (at end of period) (3)	7.8		%	7.7		%	6.2		%	7.4		%	6.4		%
Annualized funds from operations (FFO) multiple	6.9x			6.7x			7.5x			5.9x			7.1x
Annualized cash available for distribution (CAD) multiple	8.7x			8.3x			9.0x			9.7x			10.6x

Selected Balance Sheet Data:
Total assets	$	6,373,775		$	6,205,018		$	6,234,751		$	6,121,321		$	6,007,527
Total liabilities	$	3,059,930		$	3,096,495		$	3,084,814		$	3,232,255		$	3,044,362
Gross book value of real estate assets (4)	$	6,732,706		$	6,756,344		$	6,624,862		$	6,625,390		$	6,463,324
Equity investments (book value)	$	173,721		$	166,626		$	173,619		$	158,822		$	161,045
Total debt / gross book value of real estate assets, plus equity investments (4)	40.9		%	41.6		%	42.4		%	44.1		%	42.5		%

Book Capitalization:
Total debt	$	2,826,691		$	2,879,274		$	2,880,928		$	2,992,650		$	2,816,201
Plus: total stockholders’ equity	3,313,845			3,108,523			3,149,937			2,889,066			2,963,165
Total book capitalization	$	6,140,536		$	5,987,797		$	6,030,865		$	5,881,716		$	5,779,366
Total debt / total book capitalization	46.0		%	48.1		%	47.8		%	50.9		%	48.7		%

Market Capitalization:
Total debt (book value)	$	2,826,691		$	2,879,274		$	2,880,928		$	2,992,650		$	2,816,201
Plus: market value of preferred shares (at end of period)	662,950			595,043			625,863			563,722			567,990
Plus: market value of common shares (at end of period)	1,846,750			1,604,565			2,010,041			1,448,374			1,683,427
Total market capitalization	$	5,336,391		$	5,078,882		$	5,516,832		$	5,004,746		$	5,067,618
Total debt / total market capitalization	53.0		%	56.7		%	52.2		%	59.8		%	55.6		%

Selected Income Statement Data (5):
Rental income	$	218,035		$	213,966		$	213,626		$	213,339		$	206,587
Property net operating income (NOI) (6)	$	124,313		$	124,819		$	124,052		$	124,073		$	118,283
EBITDA (7)	$	116,414		$	118,276		$	119,285		$	117,447		$	114,560
NOI margin (8)	57.0		%	58.3		%	58.1		%	58.2		%	57.3		%
Net income (loss)	$	65,810		$	9,998		$	37,297		$	(10,253	)	$	72,199
Preferred distributions	$	(12,667	)	$	(12,667	)	$	(12,667	)	$	(12,667	)	$	(12,667	)
Net income (loss) available for common shareholders	$	53,143		$	(2,669	)	$	24,630		$	(22,920	)	$	59,532
FFO (9)	$	73,409		$	72,870		$	72,625		$	75,298		$	73,455
FFO available for common shareholders (9)	$	60,742		$	60,203		$	59,958		$	62,631		$	60,788
CAD (10)	$	47,902		$	48,373		$	49,151		$	37,437		$	39,790
Common distributions paid	$	32,298		$	31,007		$	26,863		$	26,863		$	26,845

Per Share Data (2):
Net income (loss) available for common shareholders – basic and diluted	$	0.82		$	(0.04	)	$	0.43		$	(0.41	)	$	1.06
FFO available for common shareholders – basic (9)	$	0.93		$	0.93		$	1.06		$	1.12		$	1.09
FFO available for common shareholders – diluted (2) (9)	$	0.92		$	0.92		$	1.03		$	1.09		$	1.06
CAD (10)	$	0.73		$	0.75		$	0.87		$	0.67		$	0.71
Common distributions paid (3)	$	0.50		$	0.48		$	0.48		$	0.48		$	0.48
FFO payout ratio (3)	53.2		%	51.5		%	44.8		%	42.9		%	44.2		%
CAD payout ratio	67.4		%	64.1		%	54.7		%	71.8		%	67.5		%

Coverage Ratios:
EBITDA (7) / interest expense	2.6x			2.6x			2.6x			2.7x			2.7x
EBITDA (7) / interest expense and preferred distributions	2.0x			2.0x			2.0x			2.1x			2.1x

(1) Amounts have been adjusted, where applicable, for a 1 for 4 reverse stock split that was effective on 7/1/10.

(2) As of 9/30/2010, we had 15,180 preferred shares outstanding that were convertible into 7,298 common shares. See Exhibit E for calculations of diluted net income, funds from operations, or FFO, and weighted average common shares outstanding.

(3) The amounts stated are based on the amounts paid during the periods.

(4) Gross book value of real estate assets is real estate properties, at cost, including acquisition costs, purchase price allocations less impairment writedowns, if any.

(5) Prior periods reflect amounts previously reported and excludes retroactive adjustments for one property reclassified from discontinued operations during the fourth quarter of 2009 and one property reclassified from continuing operations during the third quarter of 2010.

(6) Property net operating income, or NOI, is defined as rental income from real estate less property operating expenses; see Exhibit A for calculation of NOI and reconciliation of NOI to Net Income.

(7) See Exhibit B for calculation of EBITDA.

(8) NOI margin is defined as property net operating income, or NOI, as a percentage of rental income.

(9) See Exhibit C for calculation of FFO and FFO available for common shareholders.

(10) See Exhibit D for calculation of CAD.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

CONSOLIDATED BALANCE SHEETS

(amounts in thousands, except share data)

	As of September 30,			As of December 31,
	2010			2009
ASSETS
Real estate properties:
Land	$	1,238,611		$	1,237,808
Buildings and improvements	5,150,677			5,085,873
	6,389,288			6,323,681
Accumulated depreciation	(911,211		)	(884,421		)
	5,478,077			5,439,260
Properties held for sale	8,297			8,263
Acquired real estate leases, net	179,357			166,453
Equity investments	173,721			158,822
Cash and cash equivalents	174,723			18,204
Restricted cash	7,075			11,662
Rents receivable, net of allowance for doubtful accounts of $12,415 and $10,945, respectively	198,899			194,358
Other assets, net	153,626			124,299
Total assets	$	6,373,775		$	6,121,321

LIABILITIES AND SHAREHOLDERS’ EQUITY
Revolving credit facility	$	—		$	110,000
Senior unsecured debt, net	2,474,116			2,258,466
Mortgage notes payable, net	352,575			624,184
Other liabilities related to properties held for sale	11			14
Accounts payable and accrued expenses	108,792			103,608
Acquired real estate lease obligations, net	43,513			47,348
Distributions payable	—			26,863
Rent collected in advance	32,418			30,366
Security deposits	22,903			23,097
Due to affiliates	25,602			8,309
Total liabilities	3,059,930			3,232,255

Shareholders’ equity:
Preferred shares of beneficial interest, $0.01 par value:
50,000,000 shares authorized;
Series B preferred shares; 8 3/4% cumulative redeemable at par on or after September 12, 2007; 7,000,000 shares issued and and outstanding, aggregate liquidation preference $175,000	169,079			169,079
Series C preferred shares; 7 1/8% cumulative redeemable at par on or after February 15, 2011; 6,000,000 shares issued and outstanding, aggregate liquidation preference $150,000	145,015			145,015
Series D preferred shares; 6 1/2% cumulative convertible; 15,180,000 shares issued and outstanding, aggregate liquidation preference $379,500	368,270			368,270
Common shares of beneficial interest, $0.01 par value:
350,000,000 shares authorized; 72,138,686 and 55,965,061 shares issued and outstanding, respectively	721			560
Additional paid in capital	3,354,771			2,925,845
Cumulative net income	2,350,033			2,236,928
Cumulative common distributions	(2,639,887		)	(2,576,582		)
Cumulative preferred distributions	(420,597		)	(382,596		)
Cumulative other comprehensive (loss) income	(13,560		)	2,547
Total shareholders’ equity	3,313,845			2,889,066
Total liabilities and shareholders’ equity	$	6,373,775		$	6,121,321

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

CONSOLIDATED STATEMENTS OF INCOME

(amounts in thousands, except per share data)

	For the Three Months Ended						For the Nine Months Ended
	9/30/2010			9/30/2009			9/30/2010			9/30/2009

Rental income (1)	$	218,035		$	206,032		$	644,725		$	634,577

Expenses:
Operating expenses	93,722			87,881			271,664			265,486
Depreciation and amortization	48,520			48,042			147,869			145,787
General and administrative	10,658			9,607			30,888			28,844
Acquisition related costs	1,559			1,539			2,972			2,287
Total expenses	154,459			147,069			453,393			442,404

Operating income	63,576			58,963			191,332			192,173

Interest and other income	572			331			2,137			839
Interest expense (including amortization of debt discounts, premiums and deferred financing fees of $1,839, $1,574, $5,644 and $5,102, respectively)	(44,743		)	(41,786		)	(137,506		)	(129,912		)
Loss on asset impairment	—			—			(21,491		)	—
(Loss) gain on early extinguishment of debt	(1,044		)	—			(1,044		)	20,686
Equity in earnings of equity investments	1,999			2,957			6,643			3,818
Gain on issuance of shares by equity investee	18,390			—			34,808			—
Gain on sale of properties	22,832			—			34,336			—
Income from continuing operations before income tax expense	61,582			20,465			109,215			87,604
Income tax benefit (expense)	34			(176		)	(329		)	(518		)
Income from continuing operations	61,616			20,289			108,886			87,086
Discontinued operations:
(Loss) income from discontinued operations (1)	(374		)	1,804			(349		)	8,684
Gain on sale of properties	4,568			50,106			4,568			79,157
Net income	65,810			72,199			113,105			174,927
Preferred distributions	(12,667		)	(12,667		)	(38,001		)	(38,001		)
Net income available for common shareholders	$	53,143		$	59,532		$	75,104		$	136,926

Weighted average common shares outstanding – basic	65,173			55,932			62,198			56,085

Weighted average common shares outstanding – diluted (2)	72,471			63,230			69,496			63,383

Earnings per common share:
Income from continuing operations available for common shareholders – basic and diluted (2)	$	0.75		$	0.14		$	1.14		$	0.88
Income from discontinued operations – basic and diluted (2)	$	0.06		$	0.93		$	0.07		$	1.57
Net income available for common shareholders – basic and diluted (2)	$	0.82		$	1.06		$	1.21		$	2.44

Additional Data:
General and administrative expenses / rental income	4.89		%	4.66		%	4.79		%	4.55		%
General and administrative expenses / total assets (at end of period)	0.17		%	0.16		%	0.48		%	0.48		%

Continuing Operations:
Non cash straight line rent adjustments (1)	$	3,461		$	5,548		$	8,069		$	6,586
Lease value amortization (1)	$	(1,923	)	$	(3,317	)	$	(5,211	)	$	(8,078	)
Lease termination fees included in rental income	$	554		$	559		$	1,839		$	1,065
Capitalized interest expense	$	—		$	—		$	—		$	—

Discontinued Operations:
Non cash straight line rent adjustments (1)	$	(1	)	$	40		$	(6	)	$	338
Lease value amortization (1)	$	—		$	—		$	—		$	—

(1) We report rental income on a straight line basis over the terms of the respective leases; rental income and income from discontinued operations includes non-cash straight line rent adjustments. Rental income and income from discontinued operations also includes non-cash amortization of intangible lease assets and liabilities.

(2) As of 9/30/2010, we had 15,180 series D preferred shares outstanding that were convertible into 7,298 common shares. See Exhibit E for calculations of diluted net income and weighted average common shares outstanding.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

CONSOLIDATED STATEMENTS OF CASH FLOWS

(amounts in thousands)

	For the Nine Months Ended
	9/30/2010			9/30/2009
Cash flows from operating activities:
Net income	$	113,105		$	174,927
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	117,575			116,412
Amortization of debt discounts, premiums and deferred financing fees	5,644			5,102
Amortization of acquired real estate leases	23,420			26,584
Other amortization	12,216			11,241
Loss on asset impairment	21,491			—
Loss (gain) on early extinguishment of debt	1,044			(20,686		)
Equity in earnings of equity investments	(6,643		)	(3,818		)
Gain on issuance of shares by equity investee	(34,808		)	—
Distributions of earnings from equity investments	6,660			—
Gain on sale of properties	(38,904		)	(79,157		)
Change in assets and liabilities:
Decrease (increase) in restricted cash	5,808			(801		)
Increase in rents receivable and other assets	(36,581		)	(20,525		)
(Decrease) increase in accounts payable and accrued expenses	(10,951		)	169
Increase in rent collected in advance	2,049			2,031
(Decrease) increase in security deposits	(59		)	3,469
Increase in due to affiliates	17,293			18,644
Cash provided by operating activities	198,359			233,592

Cash flows from investing activities:
Real estate acquisitions and improvements	(406,983		)	(470,564		)
Proceeds from investment in marketable pass through certificates	8,000			—
Investment in marketable pass through certificates	—			(6,760		)
Proceeds from sale of properties, net	230,911			212,057
Distributions in excess of earnings from equity investments	5,379			—
Investment in Affiliates Insurance Company	(75		)	(5,109		)
Increase in restricted cash	(1,221		)	—
Cash used in investing activities	(163,989		)	(270,376		)

Cash flows from financing activities:
Proceeds from issuance of common shares, net	430,778			—
Repurchase and retirement of common shares	—			(14,486		)
Repurchase and retirement of outstanding debt securities	—			(88,251		)
Proceeds from borrowings	1,148,632			605,000
Payments on borrowings	(1,317,027		)	(321,728		)
Deferred financing fees	(9,565		)	(7,026		)
Distributions to common shareholders	(90,168		)	(81,015		)
Distributions to preferred shareholders	(38,001		)	(38,001		)
Purchase of noncontrolling equity interest	(2,500		)	—
Cash provided by financing activities	122,149			54,493

Increase in cash and cash equivalents	156,519			17,709
Cash and cash equivalents at beginning of period	18,204			15,518
Cash and cash equivalents at end of period	$	174,723		$	33,227

Supplemental cash flow information:
Interest paid	$	142,311		$	136,728

Non-cash investing activities:
Real estate acquisitions	$	—		$	(9	)
Investment in real estate mortgage receivable	(8,288		)	—
Net assets transferred to Government Properties Income Trust	—			395,317

Non-cash financing activities:
Issuance of common shares	$	896		$	628
Secured credit facility and related deferred financing fees transferred to Government Properties Income Trust	—			(243,199		)

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

SUMMARY OF EQUITY INVESTMENTS

(dollars in thousands)

	9/30/2010			6/30/2010			3/31/2010			12/31/2009			9/30/2009
Common shares owned by CWH:
Government Properties Income Trust (1)	9,950,000			9,950,000			9,950,000			9,950,000			9,950,000
Affiliates Insurance Company	20,000			20,000			20,000			20,000			20,000

Percent owned by CWH:
Government Properties Income Trust (1)	24.6		%	31.8		%	31.8		%	46.3		%	46.3		%
Affiliates Insurance Company	14.3		%	14.3		%	14.3		%	14.3		%	16.7		%

Percent of CWH’s total assets (book value):
Government Properties Income Trust (1)	2.6		%	2.6		%	2.7		%	2.5		%	2.6		%
Affiliates Insurance Company	0.1		%	0.1		%	0.1		%	0.1		%	0.1		%
Total	2.7		%	2.7		%	2.8		%	2.6		%	2.7		%

Carrying book value on CWH’s balance sheet:
Government Properties Income Trust (1)	$	168,663		$	161,634		$	168,627		$	153,822		$	156,068
Affiliates Insurance Company	5,058			4,992			4,992			5,000			4,977
Total	$	173,721		$	166,626		$	173,619		$	158,822		$	161,045

Market value of shares owned by CWH:
Government Properties Income Trust (1)	$	265,665		$	253,924		$	258,800		$	228,651		$	238,900
Affiliates Insurance Company	N/A			N/A			N/A			N/A			N/A
Total	$	265,665		$	253,924		$	258,800		$	228,651		$	238,900

	For the Three Months Ended					For the Nine Months Ended
	9/30/2010		9/30/2009			9/30/2010			9/30/2009
Equity in earnings (loss) of equity investments:
Government Properties Income Trust (1)	$	1,964	$	2,980		$	6,660		$	3,950
Affiliates Insurance Company	35		(23		)	(17		)	(132		)
	$	1,999	$	2,957		$	6,643		$	3,818

EBITDA from equity investments:
Government Properties Income Trust (1)	$	4,043	$	5,320		$	12,872		$	6,787
Affiliates Insurance Company	35		(23		)	(17		)	(132		)
	$	4,078	$	5,297		$	12,855		$	6,655

FFO from equity investments:
Government Properties Income Trust (1)	$	4,188	$	4,638		$	12,664		$	5,917
Affiliates Insurance Company	35		(23		)	(17		)	(132		)
	$	4,223	$	4,615		$	12,647		$	5,785

Cash distributions from equity investments:
Government Properties Income Trust (1)	$	4,079	$	—		$	12,039		$	—
Affiliates Insurance Company	—		—			—			—
	$	4,079	$	—		$	12,039		$	—

(1)

In January 2010, Government Properties Income Trust, or GOV, issued 9,775,000 common shares in a public offering for $21.50 per common share, raising net proceeds of approximately $199,300. As a result of this transaction, our ownership percentage in GOV was reduced from 46.3% prior to this transaction to 31.8% after this transaction, and we recognized a gain of $16,418. In August 2010, GOV issued 9,200,000 common shares in a public offering for $25.00 per common share, raising net proceeds of approximately $219,900. As a result of this transaction, our ownership percentage in GOV was reduced from 31.8% prior to this transaction to 24.6% after this transaction, and we recognized a gain of $18,390.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

DEBT SUMMARY

(dollars in thousands)

	Coupon		Interest		Principal			Maturity	Due at		Years to
	Rate		Rate (1)		Balance			Date	Maturity		Maturity

Secured Fixed Rate Debt:

Secured debt One property in Milwaukee, WI	7.435	%	7.000	%	$	29,555		6/1/2011	$	29,188	0.7
Secured debt One property in Bannockburn, IL	8.050	%	5.240	%	23,589			6/1/2012	22,719		1.7
Secured debt Two properties in Rochester, NY	6.000	%	6.000	%	4,834			10/11/2012	4,507		2.0
Secured debt One property in Macon, GA	4.950	%	6.280	%	13,010			5/11/2014	11,930		3.6
Secured debt One property in St. Cloud, MN	5.990	%	5.990	%	8,853			2/1/2015	7,580		4.3
Secured debt One property in Lenexa, KS	5.760	%	7.000	%	8,254			5/1/2016	6,116		5.6
Secured debt One property in Jacksonville, FL	6.030	%	8.000	%	41,600			5/11/2016	38,994		5.6
Secured debt One property in Birmingham, AL	7.360	%	5.610	%	12,300			8/1/2016	9,333		5.8
Secured debt One property in Philadelphia, PA (2)	2.885	%	5.660	%	175,000			12/2/2019	160,710		9.2
Secured debt One property in North Haven, CT	6.750	%	5.240	%	4,371			3/1/2022	—		11.4
Secured debt One property in Morgan Hill, CA	6.140	%	8.000	%	14,556			1/5/2023	—		12.3
Secured debt One property in East Windsor, CT	5.710	%	5.240	%	8,452			3/1/2026	—		15.4
Secured debt Two properties in Morgan Hill, CA	6.060	%	8.000	%	13,505			11/10/2027	—		17.1
Total / weighted average secured fixed rate debt	4.747	%	6.248	%	$	357,879			$	291,077	7.6

Unsecured Debt:

Unsecured Floating Rate Debt:
Revolving credit facility (LIBOR + 200 bps) (3)	2.260	%	2.260	%	$	—		8/8/2013	$	—	2.9
Senior notes due 2011 (3-MONTH LIBOR + 60 bps) (4)	0.892	%	0.892	%	168,219			3/16/2011	168,219		0.5
Total / weighted average unsecured floating rate debt	0.892	%	0.892	%	$	168,219			$	168,219	0.5

Unsecured Fixed Rate Debt:
Senior notes due 2010	8.625	%	8.770	%	$	20,000		10/1/2010	$	20,000	0.0
Senior notes due 2012	6.950	%	7.179	%	150,680			4/1/2012	150,680		1.5
Senior notes due 2013	6.500	%	6.693	%	190,980			1/15/2013	190,980		2.3
Senior notes due 2014	5.750	%	5.828	%	244,655			2/15/2014	244,655		3.4
Senior notes due 2015	6.400	%	6.601	%	186,000			2/15/2015	186,000		4.4
Senior notes due 2015	5.750	%	5.790	%	250,000			11/1/2015	250,000		5.1
Senior notes due 2016	6.250	%	6.470	%	400,000			8/15/2016	400,000		5.9
Senior notes due 2017	6.250	%	6.279	%	250,000			6/15/2017	250,000		6.7
Senior notes due 2018	6.650	%	6.768	%	250,000			1/15/2018	250,000		7.3
Senior notes due 2019	7.500	%	7.863	%	125,000			11/15/2019	125,000		9.1
Senior notes due 2020	5.875	%	6.166	%	250,000			9/15/2020	250,000		10.0
Total / weighted average unsecured fixed rate debt	6.312	%	6.478	%	$	2,317,315			$	2,317,315	5.6

Total / weighted average unsecured debt	5.945	%	6.100	%	$	2,485,534			$	2,485,534	5.3

Summary Debt:
Total / weighted average secured fixed rate debt	4.747	%	6.248	%	$	357,879			$	291,077	7.6
Total / weighted average unsecured floating rate debt	0.892	%	0.892	%	168,219				168,219		0.5
Total / weighted average unsecured fixed rate debt	6.312	%	6.478	%	2,317,315				2,317,315		5.6
Total / weighted average debt	5.794	%	6.118	%	$	2,843,413	(5)		$	2,776,611	5.6

(1)	Includes the effect of interest rate protection and mark to market accounting for certain mortgages, and discounts on unsecured notes. Excludes effects of offering and transaction costs.
(2)	Interest is payable at a spread over LIBOR but has been fixed through December 1, 2016 under a cash flow hedge which sets the rate at approximately 5.66%. No principal repayment is required for the first three years, after which the loan will be amortized on a 30 year direct reduction basis until maturity. Coupon represents floating interest rate at 9/30/2010.
(3)	Represents amounts outstanding on CWH’s $750 million revolving credit facility at 9/30/2010. Interest rate at 9/30/2010.
(4)	The notes became prepayable, at par, on September 16, 2006. Interest rate at 9/30/2010.
(5)	Total debt as of 9/30/2010, net of unamortized premiums and discounts, was $2,826,691.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

DEBT MATURITY SCHEDULE

(dollars in thousands)

	Scheduled Principal Payments During Period
	Secured			Unsecured			Unsecured						Weighted
	Fixed Rate			Floating			Fixed						Average
Year	Debt			Rate Debt			Rate Debt			Total (1)			Interest Rate
2010	$	1,113		$	—		$	20,000		$	21,113		8.5	%
2011	33,590			168,219			—			201,809			2.0	%
2012	31,492			—			150,680			182,172			7.0	%
2013	5,779			—			190,980			196,759			6.5	%
2014	17,876			—			244,655			262,531			5.7	%
2015	13,543			—			436,000			449,543			6.0	%
2016	59,768			—			400,000			459,768			6.2	%
2017	4,939			—			250,000			254,939			6.2	%
2018	5,283			—			250,000			255,283			6.6	%
2019 and thereafter	184,496			—			375,000			559,496			6.2	%
Total	$	357,879		$	168,219		$	2,317,315		$	2,843,413		6.0	%

Percent	12.6		%	5.9		%	81.5		%	100.0		%

(1)	Total debt as of 9/30/2010, net of unamortized premiums and discounts, was $2,826,691.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

LEVERAGE RATIOS, COVERAGE RATIOS AND PUBLIC DEBT COVENANTS

	As of and For the Three Months Ended
	9/30/2010		6/30/2010		3/31/2010		12/31/2009		9/30/2009
Leverage Ratios:

Total debt / total assets	44.3	%	46.4	%	46.2	%	48.9	%	46.9	%
Total debt / gross book value of real estate assets (1)	42.0	%	42.6	%	43.5	%	45.2	%	43.6	%
Total debt / gross book value of real estate assets, plus equity investments (1)	40.9	%	41.6	%	42.4	%	44.1	%	42.5	%
Total debt / total market capitalization	53.0	%	56.7	%	52.2	%	59.8	%	55.6	%
Total debt / total book capitalization	46.0	%	48.1	%	47.8	%	50.9	%	48.7	%
Secured debt / total assets	5.5	%	10.0	%	10.0	%	10.2	%	7.4	%
Variable rate debt / total debt	6.0	%	5.8	%	5.8	%	9.3	%	14.5	%
Variable rate debt / total assets	2.6	%	2.7	%	2.7	%	4.5	%	6.8	%

Coverage Ratios:

EBITDA / interest expense	2.6x		2.6x		2.6x		2.7x		2.7x
EBITDA / interest expense + preferred distributions	2.0x		2.0x		2.0x		2.1x		2.1x

Public Debt Covenants (2):

Debt / adjusted total assets (maximum 60%)	39.1	%	40.5	%	40.7	%	43.1	%	41.6	%
Secured debt / adjusted total assets (maximum 40%)	4.9	%	8.7	%	8.8	%	9.0	%	6.5	%
Consolidated income available for debt service / debt service (minimum 1.5x)	2.7x		2.6x		2.6x		2.6x		2.8x
Total unencumbered assets / unsecured debt (minimum 150% / 200%)	265.8	%	259.6	%	258.7	%	240.9	%	246.5	%

(1)

Gross book value of real estate assets is real estate properties, at cost, including properties held for sale, plus purchase price allocations and acquisition costs less impairment writedowns, if any.

(2)

Adjusted total assets and unencumbered assets includes original cost of real estate assets and excludes depreciation and amortization, accounts receivable, other intangible assets and impairment writedowns, if any. Consolidated income available for debt service is earnings from operations excluding interest expense, depreciation and amortization, taxes, loss on asset impairment and gains and losses on sales of assets and early extinguishment of debt, determined together with debt service on a pro forma basis for the four consecutive fiscal quarters most recently ended.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

TENANT IMPROVEMENTS, LEASING COSTS AND CAPITAL IMPROVEMENTS

(dollars and sq. ft. in thousands, except per sq. ft. data)

	For the Three Months Ended
	9/30/2010		6/30/2010		3/31/2010		12/31/2009		9/30/2009
Tenant improvements (TI)	$	9,803	$	7,950	$	7,212	$	11,614	$	8,727
Leasing costs (LC)	580		3,909		4,364		4,818		5,884
Total TI and LC	10,383		11,859		11,576		16,432		14,611

Building improvements (1)	2,918		943		760		6,289		1,563
Development, redevelopment and other activities (2)	5,942		7,392		679		5,431		3,305
Total capital improvements, including TI and LC	$	19,243	$	20,194	$	13,015	$	28,152	$	19,479

Sq. ft. beginning of period (3)	67,576		66,925		66,917		66,159		65,772
Sq. ft. end of period (3)	66,585		67,576		66,925		66,917		66,159
Average sq. ft. during period (3)	67,081		67,251		66,921		66,538		65,966

Building improvements per average sq. ft. during period	$	0.04	$	0.01	$	0.01	$	0.09	$	0.02

(1)	Building improvements generally include construction costs, expenditures to replace obsolete building components and expenditures that extend the useful life of existing assets.
(2)	Development, redevelopment and other activities generally include non-recurring expenditures or expenditures that we believe increase the value of our existing properties.
(3)	Square feet includes properties held for sale at the end of each period.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

2010 ACQUISITIONS AND DISPOSITIONS INFORMATION

(dollars and sq. ft. in thousands, except per sq. ft. amounts)

Acquisitions:

											Weighted
											Average
		Suburban Office/					Purchase				Remaining
Date		CBD Office/	Number of		Purchase		Price (1) /		Cap		Lease	Percent
Acquired	Location	Industrial & Other	Properties	Sq. Ft.	Price (1)		Sq. Ft.		Rate (2)		Term (3)	Leased (4)		Major Tenant

Apr-10	Denver, CO	Suburban Office	1	248	$	75,000	$	302.42	10.5	%	18.0	100.0	%	RE/MAX Realty
Apr-10	Colorado Springs, CO	Suburban Office	1	77	10,800		140.26		11.6	%	4.7	100.0	%	EMC Corporation
Jun-10	Ann Arbor, MI	Suburban Office	2	410	65,200		159.02		9.4	%	7.6	88.0	%	Thompson Reuters
Jun-10	Carson, CA	Suburban Office	2	212	27,925		131.72		9.6	%	6.2	100.0	%	Northrop Grumman
Jul-10	Stafford, VA	Suburban Office	2	118	18,750		158.90		10.9	%	2.8	90.4	%	Ocean Systems Engineering Corporation
Aug-10	Milwaukee, WI	CBD Office	1	432	80,200		185.65		8.7	%	4.3	93.0	%	Michael Best & Friedrich, LLP
Aug-10	Monterey, CA	Industrial & Other	7	NM	28,000		NM		10.1	%	16.0	100.0	%	The Wine Group
Sep-10	Greensboro, NC	CBD Office	1	324	44,650		137.81		9.4	%	5.0	85.5	%	Wells Fargo Bank
Oct-10	Various locations in Australia	Industrial & Other	10	1,435	83,200		57.98		11.4	%	4.7	90.0	%	Simon Transport Propriety Limited
Oct-10	Carson, CA	Suburban Office	3	190	22,650		119.21		9.6	%	6.0	100.0	%	Northrop Grumman
Oct-10	Chicago, IL	Suburban Office	2	631	96,250		152.54		8.6	%	7.3	90.1	%	Wilson Sporting Goods

	Total / Weighted Average		32	4,077	$	552,625	$	135.55	9.7	%	8.0	91.6	%

Dispositions:

													Sale Price
											Original		Multiple
		Suburban Office/					Original		Sale		Purchase		of Original	Book
Date		CBD Office/	Number of		Sale		Purchase		Price (1) /		Price (1) /		Purchase	Gain (Loss)
Sold	Location	Industrial & Other	Properties	Sq. Ft.	Price (1)		Price (1)		Sq. Ft.		Sq. Ft.		Price	on Sale (5)

Jun-10	Safford, AZ	Suburban Office	1	38	$	12,559	$	3,287	$	330.50	$	86.50	3.8x	$	4,543
Jun-10	Kansas City, KS	CBD Office	1	171	13,112		5,400		76.68		31.58		2.4x	3,984
Jun-10	Stoneham, MA	Suburban Office	1	98	14,709		9,195		150.09		93.83		1.6x	2,977
Jul-10	Tucson, AZ	Suburban Office	1	34	2,884		3,954		84.82		116.29		0.7x	(239		)
Jul-10	San Diego, CA	Suburban Office	1	142	16,482		17,659		116.07		124.36		0.9x	(1,676		)
Jul-10	Savannah, GA	Suburban Office	1	36	3,348		2,808		93.00		78.00		1.2x	518
Jul-10	Minneapolis, MN	CBD Office	1	200	23,231		18,817		116.16		94.09		1.2x	3,923
Jul-10	Albuquerque, NM	Suburban Office	1	29	2,394		2,552		82.55		88.00		0.9x	225
Aug-10	Washington, DC	CBD Office	1	154	51,503		36,109		334.44		234.47		1.4x	16,188
Aug-10	Boston, MA	CBD Office	1	133	23,813		15,164		179.05		114.02		1.6x	5,426
Sep-10	Oklahoma City, OK	CBD Office	1	186	8,302		24,586		44.63		132.18		0.3x	(195		)
Sep-10	Riverdale, MD	Suburban Office	1	337	41,731		47,534		123.83		141.05		0.9x	(678		)
Sep-10	Columbia, SC	Suburban Office	1	58	3,190		5,688		55.00		98.07		0.6x	(33		)
Sep-10	Columbia, SC	Suburban Office	1	51	3,927		3,993		77.00		78.29		1.0x	37
Sep-10	Memphis, TN	CBD Office	1	205	9,815		22,000		47.88		107.32		0.4x	(664		)
Sep-10	Irondequoit, NY	Suburban Office	1	310	9,750		19,000		31.45		61.29		0.5x	4,568

	Total		16	2,182	$	240,750	$	237,746	$	110.33	$	108.96	1.0x	$	38,904

(1) Represents the gross contract purchase or sale price and excludes closing costs and purchase price allocations.

(2) Represents the ratio of the estimated current GAAP based annual rental income less property operating expenses to the Purchase Price on the date of acquisition.

(3) Average remaining lease term based on rental income as of the date acquired.

(4) Percent leased as of the date acquired.

(5) Excludes deferred gains related to our ownership of GOV.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

SUMMARY RESULTS OF OPERATIONS BY PROPERTY TYPE

(dollars and sq. ft. in thousands)

	As of and For the Three Months Ended (1)						As of and For the Nine Months Ended (1)
	9/30/2010			9/30/2009			9/30/2010			9/30/2009

Number of Properties:

Suburban Office	285			285			285			285
CBD Office	41			45			41			45
Industrial & Other	193			185			193			185
Total	519			515			519			515

Square Feet (2):

Suburban Office	22,161			21,497			22,161			21,497
CBD Office	12,837			13,115			12,837			13,115
Industrial & Other	31,508			31,158			31,508			31,158
Total	66,506			65,770			66,506			65,770

Percent Leased (3):

Suburban Office	80.5		%	82.9		%	80.5		%	82.9		%
CBD Office	87.5		%	87.5		%	87.5		%	87.5		%
Industrial & Other	90.1		%	92.2		%	90.1		%	92.2		%
Total	86.4		%	88.2		%	86.4		%	88.2		%

Rental Income (4):

Suburban Office	$	95,196		$	86,804		$	276,085		$	286,842
CBD Office	83,320			81,081			251,085			235,180
Industrial & Other	39,519			38,147			117,555			112,555
Total	$	218,035		$	206,032		$	644,725		$	634,577

Property Net Operating Income (NOI) (5):

Suburban Office	$	53,051		$	48,435		$	155,491		$	164,330
CBD Office	43,048			43,372			133,567			125,161
Industrial & Other	28,214			26,344			84,003			79,600
Total	$	124,313		$	118,151		$	373,061		$	369,091

NOI Margin (6):

Suburban Office	55.7		%	55.8		%	56.3		%	57.3		%
CBD Office	51.7		%	53.5		%	53.2		%	53.2		%
Industrial & Other	71.4		%	69.1		%	71.5		%	70.7		%
Total	57.0		%	57.3		%	57.9		%	58.2		%

(1) Excludes properties classified in discontinued operations. Prior periods have been restated to reflect one property reclassified from discontinued operations during the fourth quarter of 2009 and one property reclassified from continuing operations during the third quarter of 2010.

(2) Prior periods exclude space remeasurements made during the current period.

(3) Percent leased includes (i) space being fitted out for occupancy pursuant to signed leases and (ii) space which is leased but is not occupied or is being offered for sublease by tenants.

(4) Includes some triple net lease rental income.

(5) Property net operating income, or NOI, is defined as property rental income less property operating expenses; see Exhibit A for calculation of NOI and reconciliation of NOI to Net Income.

(6) NOI margin is defined as NOI as a percentage of rental income.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

SUMMARY RESULTS OF OPERATIONS BY MAJOR MARKET

(dollars and sq. ft. in thousands)

	As of and For the Three Months Ended (1)						As of and For the Nine Months Ended (1)
	9/30/2010			9/30/2009			9/30/2010			9/30/2009
Number of Properties:
Metro Philadelphia, PA	19			19			19			19
Oahu, HI	57			57			57			57
Metro Denver, CO	8			7			8			7
Metro Washington, DC	15			15			15			15
Metro Boston, MA	18			20			18			20
Other markets	402			397			402			397
Total	519			515			519			515

Square Feet (2):
Metro Philadelphia, PA	5,292			5,285			5,292			5,285
Oahu, HI	17,914			17,914			17,914			17,914
Metro Denver, CO	2,013			1,757			2,013			1,757
Metro Washington, DC	1,495			1,869			1,495			1,869
Metro Boston, MA	2,393			2,624			2,393			2,624
Other markets	37,399			36,321			37,399			36,321
Total	66,506			65,770			66,506			65,770

Percent Leased (3):
Metro Philadelphia, PA	84.9		%	84.0		%	84.9		%	84.0		%
Oahu, HI	95.4		%	95.4		%	95.4		%	95.4		%
Metro Denver, CO	91.3		%	89.6		%	91.3		%	89.6		%
Metro Washington, DC	83.0		%	87.8		%	83.0		%	87.8		%
Metro Boston, MA	82.5		%	83.2		%	82.5		%	83.2		%
Other markets	82.5		%	85.6		%	82.5		%	85.6		%
Total	86.4		%	88.2		%	86.4		%	88.2		%

Rental Income (4):
Metro Philadelphia, PA	$	30,748		$	31,486		$	92,501		$	92,705
Oahu, HI	18,114			18,872			54,457			54,622
Metro Denver, CO	11,140			8,552			30,947			18,552
Metro Washington, DC	11,755			11,306			37,026			45,943
Metro Boston, MA	11,884			12,714			36,368			38,555
Other markets	134,394			123,102			393,426			384,200
Total	$	218,035		$	206,032		$	644,725		$	634,577

Property Net Operating Income (NOI) (5):
Metro Philadelphia, PA	$	15,303		$	16,459		$	46,425		$	47,763
Oahu, HI	13,542			13,729			40,569			41,598
Metro Denver, CO	7,383			5,323			20,517			11,444
Metro Washington, DC	7,119			6,942			22,831			28,528
Metro Boston, MA	6,075			6,900			20,140			21,321
Other markets	74,891			68,798			222,579			218,437
Total	$	124,313		$	118,151		$	373,061		$	369,091

NOI Margin (6):
Metro Philadelphia, PA	49.8		%	52.3		%	50.2		%	51.5		%
Oahu, HI	74.8		%	72.7		%	74.5		%	76.2		%
Metro Denver, CO	66.3		%	62.2		%	66.3		%	61.7		%
Metro Washington, DC	60.6		%	61.4		%	61.7		%	62.1		%
Metro Boston, MA	51.1		%	54.3		%	55.4		%	55.3		%
Other markets	55.7		%	55.9		%	56.6		%	56.9		%
Total	57.0		%	57.3		%	57.9		%	58.2		%

(1) Excludes properties classified in discontinued operations. Prior periods have been restated to reflect one property reclassifed from discontinued operations during the fourth quarter of 2009 and one property reclassified from continuing operations during the third quarter of 2010.

(2) Prior periods exclude space remeasurements made during the current period.

(3) Percent leased includes (i) space being fitted out for occupancy pursuant to signed leases and (ii) space which is leased but is not occupied or is being offered for sublease by tenants.

(4) Includes some triple net lease rental income.

(5) Property net operating income, or NOI, is defined as property rental income less property operating expenses; see Exhibit A for calculation of NOI and reconciliation of NOI to Net Income.

(6) NOI margin is defined as NOI as a percentage of rental income.

We define our major markets as markets which currently, or during either of the last two quarters, constitute 5% or more of our leaseable square feet, rental income or NOI. Major markets are based on geographic market areas as defined by CoStar, except for the Metro Philadelphia, PA market, which excludes properties located in Central Pennsylvania and Wilmington, DE. Oahu, HI includes all properties located on the island of Oahu.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

SAME PROPERTY RESULTS OF OPERATIONS BY PROPERTY TYPE

(dollars and sq. ft. in thousands)

	As of and For the Three Months Ended (1)						As of and For the Nine Months Ended (2)
	9/30/2010			9/30/2009			9/30/2010			9/30/2009

Number of Properties:

Suburban Office	276			276			272			272
CBD Office	36			36			35			35
Industrial & Other	185			185			184			184
Total	497			497			491			491

Square Feet:

Suburban Office	20,678			20,678			20,285			20,285
CBD Office	11,317			11,317			10,645			10,645
Industrial & Other	31,170			31,170			30,525			30,525
Total	63,165			63,165			61,455			61,455

Percent Leased (3):

Suburban Office	79.5		%	83.6		%	79.1		%	83.3		%
CBD Office	86.5		%	86.8		%	86.0		%	86.4		%
Industrial & Other	90.0		%	92.2		%	89.8		%	92.0		%
Total	85.9		%	88.4		%	85.6		%	88.2		%

Rental Income (4):

Suburban Office	$	81,641		$	83,878		$	236,644		$	247,239
CBD Office	71,150			72,052			197,352			200,331
Industrial & Other	38,733			38,148			113,516			111,475
Total	$	191,524		$	194,078		$	547,512		$	559,045

Property Net Operating Income (NOI) (5):

Suburban Office	$	43,091		$	47,118		$	126,736		$	138,520
CBD Office	35,879			38,515			99,944			105,435
Industrial & Other	27,557			26,358			80,413			79,499
Total	$	106,527		$	111,991		$	307,093		$	323,454

NOI Margin (6):

Suburban Office	52.8		%	56.2		%	53.6		%	56.0		%
CBD Office	50.4		%	53.5		%	50.6		%	52.6		%
Industrial & Other	71.1		%	69.1		%	70.8		%	71.3		%
Total	55.6		%	57.7		%	56.1		%	57.9		%

(1) Based on properties owned continuously since 7/1/2009 and excludes properties classified in discontinued operations.

(2) Based on properties owned continuously since 1/1/2009 and excludes properties classified in discontinued operations.

(3) Percent leased includes (i) space being fitted out for occupancy pursuant to signed leases and (ii) space which is leased but is not occupied or is being offered for sublease by tenants.

(4) Includes some triple net lease rental income.

(5) Property net operating income, or NOI, is defined as property rental income less property operating expenses; see Exhibit A for calculation of NOI and reconciliation of NOI to Net Income.

(6) NOI margin is defined as NOI as a percentage of rental income.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

SAME PROPERTY RESULTS OF OPERATIONS BY MAJOR MARKET

(dollars and sq. ft. in thousands)

	As of and For the Three Months Ended (1)						As of and For the Nine Months Ended (2)
	9/30/2010			9/30/2009			9/30/2010			9/30/2009
Number of Properties:
Metro Philadelphia, PA	19			19			19			19
Oahu, HI	57			57			57			57
Metro Denver, CO	7			7			6			6
Metro Washington, DC	11			11			11			11
Metro Boston, MA	18			18			18			18
Other markets	385			385			380			380
Total	497			497			491			491

Square Feet:
Metro Philadelphia, PA	5,292			5,292			5,292			5,292
Oahu, HI	17,914			17,914			17,914			17,914
Metro Denver, CO	1,765			1,765			1,092			1,092
Metro Washington, DC	1,136			1,136			1,136			1,136
Metro Boston, MA	2,393			2,393			2,393			2,393
Other markets	34,665			34,665			33,628			33,628
Total	63,165			63,165			61,455			61,455

Percent Leased (3):
Metro Philadelphia, PA	84.9		%	84.0		%	84.9		%	84.0		%
Oahu, HI	95.4		%	95.4		%	95.4		%	95.4		%
Metro Denver, CO	90.1		%	89.6		%	87.7		%	87.8		%
Metro Washington, DC	78.7		%	80.2		%	78.7		%	80.2		%
Metro Boston, MA	82.5		%	89.8		%	82.5		%	89.8		%
Other markets	81.5		%	85.6		%	80.9		%	85.2		%
Total	85.9		%	88.4		%	85.6		%	88.2		%

Rental Income (4):
Metro Philadelphia, PA	$	30,748		$	31,486		$	92,501		$	92,705
Oahu, HI	18,114			18,872			54,457			54,622
Metro Denver, CO	9,184			8,939			11,638			11,001
Metro Washington, DC	7,037			7,082			21,328			22,572
Metro Boston, MA	11,425			11,301			33,099			34,329
Other markets	115,016			116,398			334,489			343,816
Total	$	191,524		$	194,078		$	547,512		$	559,045

Property Net Operating Income (NOI) (5):
Metro Philadelphia, PA	$	15,303		$	16,459		$	46,425		$	47,763
Oahu, HI	13,542			13,729			40,569			41,598
Metro Denver, CO	5,477			5,697			6,486			6,547
Metro Washington, DC	4,008			4,259			12,047			14,071
Metro Boston, MA	5,882			6,404			18,458			19,672
Other markets	62,315			65,443			183,108			193,803
Total	$	106,527		$	111,991		$	307,093		$	323,454

NOI Margin (6):
Metro Philadelphia, PA	49.8		%	52.3		%	50.2		%	51.5		%
Oahu, HI	74.8		%	72.7		%	74.5		%	76.2		%
Metro Denver, CO	59.6		%	63.7		%	55.7		%	59.5		%
Metro Washington, DC	57.0		%	60.1		%	56.5		%	62.3		%
Metro Boston, MA	51.5		%	56.7		%	55.8		%	57.3		%
Other markets	54.2		%	56.2		%	54.7		%	56.4		%
Total	55.6		%	57.7		%	56.1		%	57.9		%

(1) Based on properties owned continuously since 7/1/2009 and excludes properties classified in discontinued operations.

(2) Based on properties owned continuously since 1/1/2009 and excludes properties classified in discontinued operations.

(3) Percent leased includes (i) space being fitted out for occupancy pursuant to signed leases and (ii) space which is leased but is not occupied or is being offered for sublease by tenants.

(4) Includes some triple net lease rental income.

(5) Property net operating income, or NOI, is defined as property rental income less property operating expenses; see Exhibit A for calculation of NOI and reconciliation of NOI to Net Income.

(6) NOI margin is defined as NOI as a percentage of rental income.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

PORTFOLIO SUMMARY BY PROPERTY TYPE AND MAJOR MARKET (1)

(sq. ft. and dollars in thousands)

	Number of Properties As of September 30, 2010
	Suburban				Industrial &				% of
Major Market	Office		CBD Office		Other		Total		Total
Metro Philadelphia, PA	14		5		—		19		3.7	%
Oahu, HI	—		—		57		57		11.0	%
Metro Denver, CO	6		1		1		8		1.5	%
Metro Washington, DC	12		3		—		15		2.9	%
Metro Boston, MA	16		2		—		18		3.4	%
Other markets	237		30		135		402		77.5	%
Total	285		41		193		519		100.0	%
% of Total	54.9	%	7.9	%	37.2	%	100.0	%

	Total Square Feet As of September 30, 2010
	Suburban				Industrial &		% of
Major Market	Office		CBD Office		Other		Total		Total
Metro Philadelphia, PA	700		4,592		—		5,292		8.0	%
Oahu, HI	—		—		17,914		17,914		27.0	%
Metro Denver, CO	788		672		553		2,013		3.0	%
Metro Washington, DC	1,067		428		—		1,495		2.2	%
Metro Boston, MA	2,003		390		—		2,393		3.6	%
Other markets	17,603		6,755		13,041		37,399		56.2	%
Total	22,161		12,837		31,508		66,506		100.0	%
% of Total	33.3	%	19.3	%	47.4	%	100.0	%

	NOI for the Three Months Ended September 30, 2010 (2)
	Suburban						Industrial &						% of
Major Market	Office			CBD Office			Other			Total			Total
Metro Philadelphia, PA	$	1,191		$	14,112		$	—		$	15,303		12.3	%
Oahu, HI	—			—			13,542			13,542			10.9	%
Metro Denver, CO	2,773			3,409			1,201			7,383			5.9	%
Metro Washington, DC	4,372			2,747			—			7,119			5.7	%
Metro Boston, MA	4,384			1,691			—			6,075			4.9	%
Other markets	40,331			21,089			13,471			74,891			60.3	%
Total	$	53,051		$	43,048		$	28,214		$	124,313		100.0	%
% of Total	42.7		%	34.6		%	22.7		%	100.0		%

(1) Excludes properties classified in discontinued operations.

(2) Property net operating income, or NOI, is defined as property rental income less property operating expenses; see Exhibit A for calculation of NOI and reconciliation of NOI to Net Income.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

LEASING SUMMARY (1)

(dollars and sq. ft. in thousands, except per sq. ft. data)

	As of and For the Three Months Ended
	9/30/2010			6/30/2010			3/31/2010			12/31/2009			9/30/2009
Properties	519			521			518			518			515
Total sq. ft. (2)	66,506			67,497			66,846			66,838			66,055
Percentage leased	86.4		%	86.0		%	86.6		%	87.4		%	88.0		%

Leasing Activity (sq. ft.):
New leases	733			286			425			156			518
Renewals	1,287			968			1,098			789			618
Total	2,020			1,254			1,523			945			1,136

% Change in GAAP Rent (3):
New leases	14		%	-4		%	11		%	10		%	-7		%
Renewals	-2		%	-6		%	-3		%	8		%	-1		%
Weighted average	3		%	-6		%	2		%	9		%	-3		%

Capital Commitments (4):
New leases	$	19,427		$	5,746		$	9,463		$	4,374		$	3,085
Renewals	6,911			6,778			7,703			4,976			4,095
Total	$	26,338		$	12,524		$	17,166		$	9,350		$	7,180

Capital Commitments per Sq. Ft. (4):
New leases	$	26.50		$	20.09		$	22.27		$	28.04		$	5.96
Renewals	$	5.37		$	7.00		$	7.02		$	6.31		$	6.63
Total	$	13.04		$	9.99		$	11.27		$	9.89		$	6.32

Weighted Average Lease Term by Sq. Ft. (years):
New leases	6.8			6.1			7.0			6.6			5.4
Renewals	5.2			5.1			6.1			4.7			4.4
Total	5.8			5.4			6.4			5.1			4.6

Capital Commitments per Sq. Ft. per Year:
New leases	$	3.90		$	3.29		$	3.18		$	4.25		$	1.10
Renewals	$	1.03		$	1.37		$	1.15		$	1.34		$	1.51
Total	$	2.25		$	1.85		$	1.76		$	1.94		$	1.37

(1) Prior periods reflect amounts previously reported and excludes retroactive adjustments for one property reclassified from discontinued operations during the fourth quarter of 2009 and one property reclassified from continuing operations during the third quarter of 2010.

(2) Sq. ft. measurements are subject to modest changes when space is re-measured or re-configured for new tenants.

(3) Percent difference in prior rents charged for same space. Rents include expense reimbursements and exclude lease value amortization.

(4) Represents commitments to tenant improvements (TI) and leasing costs (LC).

The above leasing summary is based on leases executed during the periods indicated.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

OCCUPANCY AND LEASING ANALYSIS BY PROPERTY TYPE AND MAJOR MARKET (1)

(dollars and sq. ft. in thousands)

	Total Sq. Ft.	Sq. Ft. Leases Executed During
	As of	Three Months Ended 9/30/2010
Property Type/Market	9/30/2010	New	Renewals	Total
Suburban Office	22,161	304	723	1,027
CBD Office	12,837	166	167	333
Industrial & Other	31,508	263	397	660
Total	66,506	733	1,287	2,020

Metro Philadelphia, PA	5,292	134	105	239
Oahu, HI	17,914	108	99	207
Metro Denver, CO	2,013	21	140	161
Metro Washington, DC	1,495	29	—	29
Metro Boston, MA	2,393	9	—	9
Other markets	37,399	432	943	1,375
Total	66,506	733	1,287	2,020

	Sq. Ft. Leased
	As of	6/30/2010				New and	Acquisitions /		As of	9/30/2010
	6/30/2010	% Leased (2)		Expired		Renewals	(Sales)		9/30/2010	% Leased
Suburban Office	18,383	79.8	%	(1,065	)	1,027	(495	)	17,850	80.5	%
CBD Office	11,236	86.8	%	(301	)	333	(40	)	11,228	87.5	%
Industrial & Other	28,428	90.2	%	(686	)	660	—		28,402	90.1	%
Total	58,047	86.0	%	(2,052	)	2,020	(535	)	57,480	86.4	%

Metro Philadelphia, PA	4,424	83.7	%	(170	)	239	—		4,493	84.9	%
Oahu, HI	16,965	94.7	%	(88	)	207	—		17,084	95.4	%
Metro Denver, CO	1,821	90.4	%	(143	)	161	—		1,839	91.3	%
Metro Washington, DC	1,611	86.2	%	(15	)	29	(384	)	1,241	83.0	%
Metro Boston, MA	2,098	83.1	%	—		9	(132	)	1,975	82.5	%
Other markets	31,128	82.2	%	(1,636	)	1,375	(19	)	30,848	82.5	%
Total	58,047	86.0	%	(2,052	)	2,020	(535	)	57,480	86.4	%

(1) Excludes properties classified in discontinued operations.

(2) Based on total sq. ft. as of June 30, 2010; excludes effects of space remeasurements during the period.

We define our major markets as markets which currently, or during either of the last two quarters, constitute 5% or more of our leaseable square feet, rental income or NOI. Major markets are based on geographic market areas as defined by CoStar, except for the Metro Philadelphia, PA market, which excludes Central Pennsylvania and Wilmington, DE. Oahu, HI includes all properties located on the island of Oahu.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

TENANTS REPRESENTING 1% OR MORE OF TOTAL RENT (1)

(sq. ft. in thousands)

			% of Total		% of Rental
Tenant		Sq. Ft. (2)	Sq. Ft. (2)		Income (3)		Expiration
1	Expedia, Inc.	349	0.6	%	2.0	%	2018
2	PNC Financial Services Group	613	1.1	%	1.8	%	2011 to 2021
3	John Wiley & Sons, Inc.	. 342	0.6	%	1.8	%	2017
4	GlaxoSmithKline plc	608	1.1	%	1.7	%	2013
5	U.S. Government (4)	470	0.8	%	1.6	%	2010 to 2021
6	Wells Fargo Bank	477	0.8	%	1.4	%	2010 to 2017
7	Jones Day (law firm)	407	0.7	%	1.2	%	2012, 2019
8	The Bank of New York Mellon Corp.	390	0.7	%	1.1	%	2011, 2012, 2015, 2020
9	Ballard Spahr Andrews & Ingersoll (law firm)	269	0.5	%	1.1	%	2011, 2012, 2015
10	Flextronics International Ltd.	894	1.6	%	1.1	%	2014
11	JDA Software Group, Inc.	283	0.5	%	1.1	%	2012
12	ING	410	0.7	%	1.1	%	2011, 2018
13	Towers Watson	334	0.6	%	1.0	%	2010 to 2020
	Total	5,846	10.3	%	18.0	%

(1) Excludes properties classified in discontinued operations.

(2) Sq. ft. is pursuant to signed leases as of 9/30/2010, and includes (i) space being fitted out for occupancy and (ii) space which is leased but is not occupied or is being offered for sublease.

(3) Rental income is rents pursuant to signed leases as of 9/30/2010, plus estimated expense reimbursements; includes some triple net lease rents and excludes lease value amortization.

(4) Including CWH’s 24.6% pro rata ownership of GOV, the U.S. Government represents 1,723 sq. ft., or 2.9% of total sq. ft. and 4.7% of total rental income.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

THREE YEAR LEASE EXPIRATION SCHEDULE BY PROPERTY TYPE (1)

(dollars and sq. ft. in thousands)

	Total as of 9/30/2010			2010			2011			2012			2013 and Thereafter

Suburban Office:
Total sq. ft.	22,161
Leased sq. ft. (2)	17,850			1,022			2,829			2,817			11,182
Percent	100.0		%	5.7		%	15.8		%	15.8		%	62.7		%
Annualized rental income (3)	$	371,436		$	21,966		$	56,947		$	59,824		$	232,699
Percent	100.0		%	5.9		%	15.3		%	16.1		%	62.7		%

CBD Office:
Total sq. ft.	12,837
Leased sq. ft. (2)	11,228			372			507			1,230			9,119
Percent	100.0		%	3.3		%	4.5		%	11.0		%	81.2		%
Annualized rental income (3)	$	336,171		$	10,174		$	17,283		$	36,183		$	272,531
Percent	100.0		%	3.0		%	5.1		%	10.8		%	81.1		%

Industrial & Other:
Total sq. ft.	31,508
Leased sq. ft. (2)	28,402			2,229			1,923			1,417			22,833
Percent	100.0		%	7.8		%	6.8		%	5.0		%	80.4		%
Annualized rental income (3)	$	162,726		$	14,932		$	10,489		$	7,288		$	130,017
Percent	100.0		%	9.2		%	6.4		%	4.5		%	79.9		%

Total:
Total sq. ft.	66,506
Leased sq. ft. (2)	57,480			3,623			5,259			5,464			43,134
Percent	100.0		%	6.3		%	9.1		%	9.5		%	75.1		%
Annualized rental income (3)	$	870,333		$	47,072		$	84,719		$	103,295		$	635,247
Percent	100.0		%	5.4		%	9.7		%	11.9		%	73.0		%

(1) Excludes properties classified in discontinued operations.

(2) Sq. ft. is pursuant to signed leases as of 9/30/2010, and includes (i) space being fitted out for occupancy and (ii) space which is leased but is not occupied or is being offered for sublease.

(3) Annualized rental income is rents pursuant to signed leases as of 9/30/2010, plus estimated expense reimbursements; includes some triple net lease rents and excludes lease value amortization.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

THREE YEAR LEASE EXPIRATION SCHEDULE BY MAJOR MARKET (1)

(dollars and sq. ft. in thousands)

	Total as of 9/30/2010			2010			2011			2012			2013 and Thereafter
Metro Philadelphia, PA:
Total sq. ft.	5,292
Leased sq. ft. (2)	4,493			199			181			405			3,708
Percent	100.0		%	4.4		%	4.0		%	9.0		%	82.6		%
Annualized rental income (3)	$	125,147		$	3,142		$	5,311		$	11,074		$	105,620
Percent	100.0		%	2.5		%	4.2		%	8.8		%	84.5		%
Oahu, HI:
Total sq. ft.	17,914
Leased sq. ft. (2)	17,084			290			669			925			15,200
Percent	100.0		%	1.7		%	3.9		%	5.4		%	89.0		%
Annualized rental income (3)	$	75,491		$	2,259		$	2,939		$	3,627		$	66,666
Percent	100.0		%	3.0		%	3.9		%	4.8		%	88.3		%
Metro Denver, CO:
Total sq. ft.	2,013
Leased sq. ft. (2)	1,839			80			131			346			1,282
Percent	100.0		%	4.4		%	7.1		%	18.8		%	69.7		%
Annualized rental income (3)	$	44,979		$	2,902		$	3,579		$	6,537		$	31,961
Percent	100.0		%	6.5		%	8.0		%	14.5		%	71.0		%
Metro Washington, DC:
Total sq. ft.	1,495
Leased sq. ft. (2)	1,241			3			29			386			823
Percent	100.0		%	0.2		%	2.3		%	31.1		%	66.4		%
Annualized rental income (3)	$	38,572		$	105		$	890		$	13,308		$	24,269
Percent	100.0		%	0.3		%	2.3		%	34.5		%	62.9		%
Metro Boston, MA:
Total sq. ft.	2,393
Leased sq. ft. (2)	1,975			53			399			63			1,460
Percent	100.0		%	2.7		%	20.2		%	3.2		%	73.9		%
Annualized rental income (3)	$	46,590		$	1,709		$	10,240		$	2,586		$	32,055
Percent	100.0		%	3.7		%	22.0		%	5.6		%	68.7		%
Other markets:
Total sq. ft.	37,399
Leased sq. ft. (2)	30,848			2,998			3,850			3,339			20,661
Percent	100.0		%	9.7		%	12.5		%	10.8		%	67.0		%
Annualized rental income (3)	$	539,554		$	36,955		$	61,760		$	66,163		$	374,676
Percent	100.0		%	6.8		%	11.4		%	12.3		%	69.5		%
Total:
Total sq. ft.	66,506
Leased sq. ft. (2)	57,480			3,623			5,259			5,464			43,134
Percent	100.0		%	6.3		%	9.1		%	9.5		%	75.1		%
Annualized rental income (3)	$	870,333		$	47,072		$	84,719		$	103,295		$	635,247
Percent	100.0		%	5.4		%	9.7		%	11.9		%	73.0		%

(1) Excludes properties classified in discontinued operations.

(2) Sq. ft. is pursuant to signed leases as of 9/30/2010, and includes (i) space being fitted out for occupancy and (ii) space which is leased but is not occupied or is being offered for sublease.

(3) Annualized rental income is rents pursuant to signed leases as of 9/30/2010, plus estimated expense reimbursements; includes some triple net lease rents and excludes lease value amortization.

We define our major markets as markets which currently, or during either of the last two quarters, constitute 5% or more of our leaseable square feet, rental income or NOI. Major markets are based on geographic market areas as defined by CoStar, except for the Metro Philadelphia, PA market, which excludes Central Pennsylvania and Wilmington, DE. Oahu, HI includes all properties located on the island of Oahu.

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

PORTFOLIO LEASE EXPIRATION SCHEDULE (1)

(dollars and sq. ft. in thousands)

	Sq. Ft. Expiring (2)	% of Sq. Ft. Expiring		Cumulative % of Sq. Ft. Expiring		Annualized Rental Income Expiring (3)		% of Annualized Rental Income Expiring		Cumulative % of Annualized Rental Income Expiring
2010	3,623	6.3	%	6.3	%	$	47,072	5.4	%	5.4	%
2011	5,259	9.1	%	15.4	%	84,719		9.7	%	15.1	%
2012	5,464	9.5	%	24.9	%	103,295		11.9	%	27.0	%
2013	5,696	9.9	%	34.8	%	100,713		11.5	%	38.5	%
2014	4,490	7.8	%	42.6	%	77,599		8.9	%	47.4	%
2015	3,657	6.4	%	49.0	%	77,927		9.0	%	56.4	%
2016	3,329	5.8	%	54.8	%	56,147		6.5	%	62.9	%
2017	2,923	5.1	%	59.9	%	77,712		8.9	%	71.8	%
2018	2,256	4.0	%	63.9	%	52,366		6.0	%	77.8	%
2019	3,467	6.0	%	69.9	%	42,571		4.9	%	82.7	%
Thereafter	17,316	30.1	%	100.0	%	150,212		17.3	%	100.0	%
Total	57,480	100.0	%			$	870,333	100.0	%

Weighted average remaining lease term (in years)	7.8					5.8

(1) Excludes properties classified in discontinued operations.

(2) Sq. ft. is pursuant to signed leases as of 9/30/2010, and includes (i) space being fitted out for occupancy and (ii) space which is leased but is not occupied or is being offered for sublease.

(3) Annualized rental income is rents pursuant to signed leases as of 9/30/2010, plus estimated expense reimbursements; includes some triple net lease rents and excludes lease value amortization.

EXHIBIT A

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

CALCULATION AND RECONCILIATION OF PROPERTY NET OPERATING INCOME (NOI)

(amounts in thousands)

	For the Three Months Ended						For the Nine Months Ended
	9/30/2010			9/30/2009			9/30/2010			9/30/2009

Calculation of NOI (1):
Rental income	$	218,035		$	206,032		$	644,725		$	634,577
Operating expenses	(93,722		)	(87,881		)	(271,664		)	(265,486		)
Property net operating income (NOI)	$	124,313		$	118,151		$	373,061		$	369,091

Reconciliation of NOI to Net Income:

Property net operating income	$	124,313		$	118,151		$	373,061		$	369,091
Depreciation and amortization	(48,520		)	(48,042		)	(147,869		)	(145,787		)
General and administrative	(10,658		)	(9,607		)	(30,888		)	(28,844		)
Acquisition related costs	(1,559		)	(1,539		)	(2,972		)	(2,287		)
Operating income	63,576			58,963			191,332			192,173

Interest and other income	572			331			2,137			839
Interest expense	(44,743		)	(41,786		)	(137,506		)	(129,912		)
Loss on asset impairment	—			—			(21,491		)	—
(Loss) gain on early extinguishment of debt	(1,044		)	—			(1,044		)	20,686
Equity in earnings of equity investments	1,999			2,957			6,643			3,818
Gain on issuance of shares by equity investee	18,390			—			34,808			—
Gain on sale of properties	22,832			—			34,336			—
Income from continuing operations before income tax expense	61,582			20,465			109,215			87,604
Income tax benefit (expense)	34			(176		)	(329		)	(518		)
Income from continuing operations	61,616			20,289			108,886			87,086

(Loss) income from discontinued operations	(374		)	1,804			(349		)	8,684
Gain on sale of properties from discontinued operations	4,568			50,106			4,568			79,157
Net income	$	65,810		$	72,199		$	113,105		$	174,927

(1) Excludes properties classified in discontinued operations.

We compute NOI as shown above. We consider NOI to be an appropriate supplemental measure to net income because it helps both investors and management to understand the operations of our properties. We use NOI internally as a performance measure and believe NOI provides useful information to investors regarding our results of operations because it reflects only those income and expense items that are incurred at the property level and may facilitate comparisons of our operating performance between periods and among REITs. Our management also uses NOI to evaluate individual, regional and company wide property level performance. NOI excludes certain components from net income available for common shareholders in order to provide results that are more closely related to our properties’ results of operations. NOI does not represent cash generated by operating activities in accordance with U.S. generally accepted accounting principles, or GAAP, and should not be considered an alternative to net income, net income available for common shareholders or cash flow from operating activities as a measure of financial performance. Also, some REITs may calculate NOI differently than us.

EXHIBIT B

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

CALCULATION OF EBITDA

(amounts in thousands)

	For the Three Months Ended						For the Nine Months Ended
	9/30/2010			9/30/2009			9/30/2010			9/30/2009

Net income	$	65,810		$	72,199		$	113,105		$	174,927
Plus: interest expense from continuing operations	44,743			41,786			137,506			129,912
Plus: interest expense from discontinued operations	—			—			—			—
Plus: income tax (benefit) expense	(34		)	176			329			518
Plus: depreciation and amortization from continuing operations	48,520			48,042			147,869			145,787
Plus: depreciation and amortization from discontinued operations	42			123			131			372
Plus: EBITDA from equity investments	4,078			5,297			12,855			6,655
Plus: loss on asset impairment	—			—			21,491			—
Less: loss (gain) on early extinguishment of debt	1,044			—			1,044			(20,686		)
Less: gain on sale of properties	(27,400		)	(50,106		)	(38,904		)	(79,157		)
Less: equity in earnings of equity investments	(1,999		)	(2,957		)	(6,643		)	(3,818		)
Less: gain on issuance of shares by equity investee	(18,390		)	—			(34,808		)	—
EBITDA	$	116,414		$	114,560		$	353,975		$	354,510

We compute EBITDA, or earnings before interest, taxes, depreciation and amortization, as net income less gains on sales of properties, gain on early extinguishment of debt and gain on issuance of shares by equity investees, plus interest expense, income tax expense, depreciation and amortization, loss on asset impairment and EBITDA from equity investments, less equity in earnings of equity investments. We consider EBITDA to be an appropriate measure of our performance, along with net income and cash flow from operating, investing and financing activities. We believe EBITDA provides useful information to investors because by excluding the effects of certain historical costs noted above, EBITDA can facilitate a comparison of our current operating performance with our past operating performance and of operating performances among REITs. EBITDA does not represent cash generated by operating activities in accordance with GAAP and should not be considered an alternative to net income or cash flow from operating activities as a measure of financial performance or liquidity. Also, some REITs may calculate EBITDA differently than us.

Exhibit C

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

CALCULATION OF FUNDS FROM OPERATIONS (FFO)

(amounts in thousands, except per share data)

	For the Three Months Ended						For the Nine Months Ended
	9/30/2010			9/30/2009			9/30/2010			9/30/2009

Net income	$	65,810		$	72,199		$	113,105		$	174,927
Plus: depreciation and amortization from continuing operations	48,520			48,042			147,869			145,787
Plus: depreciation and amortization from discontinued operations	42			123			131			372
Plus: acquisition related costs (1)	1,559			1,539			2,972			2,287
Plus: FFO from equity investments	4,223			4,615			12,647			5,785
Plus: loss on asset impairment	—			—			21,491			—
Less: loss (gain) on early extinguishment of debt	1,044			—			1,044			(20,686		)
Less: gain on sale of properties	(27,400		)	(50,106		)	(38,904		)	(79,157		)
Less: equity in earnings of equity investments	(1,999		)	(2,957		)	(6,643		)	(3,818		)
Less: gain on issuance of shares by equity investee	(18,390		)	—			(34,808		)	—
FFO	73,409			73,455			218,904			225,497
Less: preferred distributions	(12,667		)	(12,667		)	(38,001		)	(38,001		)
FFO available for common shareholders	$	60,742		$	60,788		$	180,903		$	187,496

Weighted average common shares outstanding — basic	65,173			55,932			62,198			56,085

Weighted average common shares outstanding — diluted (2)	72,471			63,230			69,496			63,383

FFO available for common shareholders per share — basic	$	0.93		$	1.09		$	2.91		$	3.34

FFO available for common shareholders per share — diluted (2)	$	0.92		$	1.06		$	2.87		$	3.25

(1) Represents costs associated with acquisitions, including costs that are expensed pursuant to the Business Combinations Topic of The FASB Accounting Standards CodificationTM.

(2) At 9/30/2010, we had 15,180 series D preferred shares outstanding that were convertible into 7,298 common shares. See Exhibit E for calculations of diluted FFO available for common shareholders and weighted average common shares outstanding.

We compute FFO, FFO available for common shareholders and diluted FFO available for common shareholders as shown above. Our calculation of FFO differs from the National Association of Real Estate Investment Trusts, or NAREIT, definition because we exclude acquisition related costs as described in Note 1 above, gains from equity investments, gain on early extinguishment of debt, loss on early extinguishment of debt unless settled in cash, and loss on asset impairment. We consider FFO to be an appropriate measure of performance for a REIT, along with net income and cash flow from operating, investing and financing activities. We believe that FFO provides useful information to investors because, by excluding the effects of certain historical amounts, such as depreciation expense and items referred to above, FFO can facilitate a comparison of operating performance between periods and among REITs. FFO does not represent cash generated by operating activities in accordance with GAAP, and should not be considered an alternative to net income or cash flow from operating activities as a measure of financial performance or liquidity. FFO is among the important factors considered by our Board of Trustees in determining the amount of distributions to shareholders. Also, some REITs may calculate FFO differently than us.

Exhibit D

CommonWealth REIT

Supplemental Operating and Financial Data

September 30, 2010

CALCULATION OF CASH AVAILABLE FOR DISTRIBUTION (CAD)

(amounts in thousands, except per share data)

	For the Three Months Ended						For the Nine Months Ended
	9/30/2010			9/30/2009			9/30/2010			9/30/2009

FFO available for common shareholders	$	60,742		$	60,788		$	180,903		$	187,496
Plus: lease value amortization from continuing operations	1,923			3,317			5,211			8,078
Plus: lease value amortization from discontinued operations	—			—			—			—
Plus: amortization of prepaid interest and debt discounts from continuing operations	1,839			1,574			5,644			5,102
Plus: amortization of prepaid interest and debt discounts from discontinued operations	—			—			—			—
Plus: distributions from equity investments	4,079			—			12,039			—
Plus: non-cash general and administrative expenses paid in common shares (1)	303			485			778			898
Less: straight-line rent from continuing operations	(3,461		)	(5,548		)	(8,069		)	(6,586		)
Less: straight-line rent from discontinued operations	1			(40		)	6			(338		)
Less: building improvements	(2,918		)	(1,563		)	(4,621		)	(8,931		)
Less: total TI and LC	(10,383		)	(14,611		)	(33,818		)	(28,555		)
Less: FFO from equity investments	(4,223		)	(4,615		)	(12,647		)	(5,785		)
CAD	$	47,902		$	39,787		$	145,426		$	151,379

Weighted average common shares outstanding — basic	65,173			55,932			62,198			56,085

CAD per share	$	0.73		$	0.71		$	2.34		$	2.70

(1) Represents the amortized value of shares issued during the year to trustees and officers of CWH, and RMR and its employees, under CWH’s equity compensation plan.

We compute CAD, or cash available for distribution, as FFO available for common shareholders, plus lease value amortization, amortization of prepaid interest and debt discounts, and general and administrative expenses paid in common shares, less straight-line rents and capex, plus distributions from equity investments, less FFO from equity investments. We consider CAD to be an appropriate measure of our performance, along with net income and cash flow from operating, investing and financing activities. We believe CAD provides useful information to investors because CAD can facilitate a comparison of cash based operating performance between periods and among REITs. CAD does not represent cash generated by operating activities in accordance with GAAP and should not be considered an alternative to net income or cash flow from operating activities as a measure of financial performance or liquidity. Also, some REITs may calculate CAD differently than us.

		Page/Exhibit

CORPORATE INFORMATION

Company Profile		5
Investor Information		6
Research Coverage		7

FINANCIAL INFORMATION

Key Financial Data		9
Consolidated Balance Sheets		10
Consolidated Statements of Income		11
Consolidated Statements of Cash Flows		12
Summary of Equity Investments		13
Debt Summary		14
Debt Maturity Schedule		15
Leverage Ratios, Coverage Ratios and Public Debt Covenants		16
Tenant Improvements, Leasing Costs and Capital Improvements		17
2010 Acquisitions and Dispositions Information		18

PORTFOLIO AND LEASING INFORMATION

Summary Results of Operations by Property Type		20
Summary Results of Operations by Major Market		21
Same Property Results of Operations by Property Type		22
Same Property Results of Operations by Major Market		23
Portfolio Summary by Property Type and Major Market		24
Leasing Summary		25
Occupancy and Leasing Analysis by Property Type and Major Market		26
Tenants Representing 1% or More of Total Rent		27
Three Year Lease Expiration Schedule by Property Type		28
Three Year Lease Expiration Schedule by Major Market		29
Portfolio Lease Expiration Schedule		30

EXHIBITS

Calculation and Reconciliation of Property Net Operating Income (NOI)		A
Calculation of EBITDA		B
Calculation of Funds from Operations (FFO)		C
Calculation of Cash Available for Distribution (CAD)		D
Calculation of Diluted Net Income, FFO and Weighted Average Common Shares Outstanding		E

·	THE CREDIT QUALITY OF OUR TENANTS,

·	THE LIKELIHOOD THAT OUR TENANTS WILL PAY RENT, RENEW LEASES, SIGN NEW LEASES OR BE AFFECTED BY CYCLICAL ECONOMIC CONDITIONS,

·	OUR ACQUISITIONS AND SALES OF PROPERTIES,

·	OUR ABILITY TO COMPETE FOR ACQUISITIONS AND TENANCIES EFFECTIVELY,

·	OUR ABILITY TO PAY INTEREST ON AND PRINCIPAL OF OUR DEBT,

·	OUR ABILITY TO PAY DISTRIBUTIONS TO SHAREHOLDERS AND THE AMOUNT OF SUCH DISTRIBUTIONS,

·	OUR POLICIES AND PLANS REGARDING INVESTMENTS AND FINANCINGS,

·	THE FUTURE AVAILABILITY OF BORROWINGS UNDER OUR REVOLVING CREDIT FACILITY,

·	OUR TAX STATUS AS A REAL ESTATE INVESTMENT TRUST, OR REIT,

·	OUR ABILITY TO RAISE EQUITY OR DEBT, AND

·	OTHER MATTERS.

·	THE IMPACT OF CHANGES IN THE ECONOMY AND THE CAPITAL MARKETS ON US AND OUR TENANTS,

·	COMPETITION WITHIN THE REAL ESTATE INDUSTRY OR THOSE INDUSTRIES IN WHICH OUR TENANTS OPERATE,

·	ACTUAL AND POTENTIAL CONFLICTS OF INTEREST WITH OUR MANAGING TRUSTEES AND OUR MANAGER, REIT MANAGEMENT & RESEARCH LLC, OR RMR, AND ITS RELATED ENTITIES AND CLIENTS,

·	COMPLIANCE WITH, AND CHANGES TO, FEDERAL, STATE AND LOCAL LAWS AND REGULATIONS, ACCOUNTING RULES, TAX RATES AND SIMILAR MATTERS, AND

·	LIMITATIONS IMPOSED ON OUR BUSINESS AND OUR ABILITY TO SATISFY COMPLEX RULES IN ORDER FOR US TO QUALIFY AS A REIT FOR U.S. FEDERAL INCOME TAX PURPOSES.

FOR EXAMPLE:

·	IF THE AVAILIBILITY OF DEBT CAPITAL BECOMES MORE RESTRICTED, WE MAY BE UNABLE TO REFINANCE OR REPAY OUR DEBT OBLIGATIONS WHEN THEY BECOME DUE OR ON TERMS WHICH ARE AS FAVORABLE AS WE NOW HAVE,

·	THE CURRENT HIGH UNEMPLOYMENT RATE IN THE U.S. MAY CONTINUE FOR A LONG TIME OR BECOME WORSE IN THE FUTURE. SUCH CIRCUMSTANCES MAY FURTHER REDUCE DEMAND FOR LEASING OFFICE AND INDUSTRIAL SPACE. IF THE DEMAND FOR LEASING OFFICE AND INDUSTRIAL SPACE REMAINS AT CURRENT LEVELS OR BECOMES FURTHER DEPRESSED, OCCUPANCY AND OPERATING RESULTS OF OUR PROPERTIES MAY DECLINE,

·	SOME OF OUR TENANTS MAY NOT RENEW EXPIRING LEASES, AND WE MAY BE UNABLE TO LOCATE NEW TENANTS TO MAINTAIN THE HISTORICAL OCCUPANCY RATES OF OUR PROPERTIES,

·	OUR AGREEMENTS TO ACQUIRE AND SELL PROPERTIES ARE SUBJECT TO VARIOUS TERMS AND CONDITIONS, AND THESE TERMS AND CONDITIONS MAY NOT BE MET. AS A RESULT, SOME OR ALL OF THESE TRANSACTIONS MAY NOT OCCUR OR MAY BE DELAYED,

·	OUR ABILITY TO MAKE FUTURE DISTRIBUTIONS DEPENDS UPON OUR FUTURE EARNINGS. WE MAY BE UNABLE TO MAINTAIN OUR CURRENT RATE OF DISTRIBUTIONS AND FUTURE DISTRIBUTIONS MAY BE SUSPENDED OR PAID AT A LESSER RATE THAN THE DISTRIBUTIONS WE NOW PAY,

·	OUR ABILITY TO GROW OUR BUSINESS AND INCREASE OUR DISTRIBUTIONS DEPENDS IN LARGE PART UPON OUR ABILITY TO BUY PROPERTIES AND LEASE THEM FOR RENTS THAT EXCEED OUR CAPITAL COSTS. WE MAY BE UNABLE TO IDENTIFY PROPERTIES THAT WE WANT TO ACQUIRE OR TO NEGOTIATE ACCEPTABLE PURCHASE PRICES, ACQUISITION FINANCING OR LEASE TERMS FOR NEW PROPERTIES, AND

·	THE DISTRIBUTIONS WE RECEIVE FROM OUR SHARES IN GOVERNMENT PROPERTIES INCOME TRUST, OR GOV, MAY DECLINE, OR WE MAY BE UNABLE TO SELL OUR GOV SHARES FOR AN AMOUNT EQUAL TO OUR CARRYING VALUE OF THOSE SHARES.

Barry M. Portnoy	Adam D. Portnoy
Managing Trustee	Managing Trustee


Patrick F. Donelan	Frederick N. Zeytoonjian
Independent Trustee	Independent Trustee


William A. Lamkin
Independent Trustee

John A. Mannix	David M. Lepore
President & Chief Investment Officer	Senior Vice President & Chief Operating Officer

John C. Popeo
Treasurer & Chief Financial Officer

Contact Information

Investor Relations	Inquiries
CommonWealth REIT	Financial inquiries should be directed to John C. Popeo,
400 Centre Street	Treasurer and Chief Financial Officer, at (617) 332-3990
Newton, MA 02458	or jpopeo@cwhreit.com.
(t) (617) 332-3990
(f) (617) 332-2261	Investor and media inquiries should be directed to
(e-mail) info@cwhreit.com	Timothy A. Bonang, Vice President of Investor Relations, at
(website) www.cwhreit.com	(617) 796-8222 or tbonang@cwhreit.com, or
	Carlynn Finn, Manager of Investor Relations, at
	(617) 796-8222 or cfinn@cwhreit.com.

*Citigroup*	*RBC Capital Markets*
Michael Bilerman	David Rodgers
(212) 816-1383	(440) 715-2647

*Bank of America / Merrill Lynch*	*Raymond James*
James Feldman	Paul Puryear
(212) 449-6339	(727) 573-3800

*Morgan Keegan*	*Stifel Nicolaus*
Steve Swett	John Guinee
(212) 508-7585	(443) 224-1307

Debt Research Coverage

*Citigroup*	*Bank of America / Merrill Lynch*
Thomas Cook	Thomas Truxillo
(212) 723-1112	(980) 386-5212

*Credit Suisse*	*Wells Fargo Securities*
John Giordano	Thierry Perrin
(212) 538-4935	(704) 715-8455

Rating Agencies

*Moody’s Investors Service*	*Standard and Poor’s*
Lori Marks	Susan Madison
(212) 553-1098	(212) 438-4516