Summary of fixed rate/hedged and unhedged floating rate debt and their respective principal maturities

Debt	Stated Rate		Effective Interest Rate (1)		Maturity Date	2012			2013			2014			2015			2016			Thereafter			Total
Secured notes payable
San Diego	6.21	%	6.21	%	3/1/13	$	156		$	7,934		$	–		$	–		$	–		$	–		$	8,090
Suburban Washington, D.C.	6.36		6.36		9/1/13	268			26,093			–			–			–			–			26,361
San Francisco Bay	6.14		6.14		11/16/13	–			7,527			–			–			–			–			7,527
Greater Boston	5.26		5.59		4/1/14	1,846			3,839			208,683			–			–			–			214,368
Suburban Washington, D.C.	2.24		2.24		4/20/14	–			–			76,000			–			–			–			76,000
San Diego	6.05		4.88		7/1/14	55			142			6,458			–			–			–			6,655
San Diego	5.39		4.00		11/1/14	70			177			7,495			–			–			–			7,742
Seattle	6.00		6.00		11/18/14	120			240			240			–			–			–			600
Suburban Washington, D.C.	5.64		4.50		6/1/15	51			130			138			5,788			–			–			6,107
Greater Boston, San Francisco Bay, and San Diego	5.73		5.73		1/1/16	767			1,616			1,713			1,816			75,501			–			81,413
Greater Boston, San Diego, and Greater NYC	5.82		5.82		4/1/16	412			878			931			988			29,389			–			32,598
San Francisco Bay	6.35		6.35		8/1/16	1,075			2,332			2,487			2,652			126,715			–			135,261
San Diego, Suburban Washington, D.C., and Seattle	7.75		7.75		4/1/20	635			1,345			1,453			1,570			1,696			110,301			117,000
San Francisco Bay	6.50		6.50		6/1/37	8			16			17			17			19			801			878
Average/Total	5.70		5.77			5,463			52,269			305,615			12,831			233,320			111,102			720,600

$1.5 Billion unsecured senior line of credit	LIBOR+1.20		1.51		4/30/17 (2)	–			–			–			–			–			379,000			379,000

2016 Unsecured Senior Bank Term Loan	LIBOR+1.65		3.29		6/30/16 (3)	–			–			–			–			750,000			–			750,000
2017 Unsecured Senior Bank Term Loan	LIBOR+1.50		3.84		1/31/17 (4)	–			–			–			–			–			600,000			600,000

Unsecured senior notes payable (5)	4.60		4.61		4/1/22	–			–			250			–			–			550,000			550,250
Average/Subtotal			4.01			5,463			52,269			305,865			12,831			983,320			1,640,102			2,999,850
Unamortized discounts			–			(223		)	(464		)	(78		)	(12		)	(44		)	(269		)	(1,090		)
Average/Total			4.01	%		$	5,240		$	51,805		$	305,787		$	12,819		$	983,276		$	1,639,833		$	2,998,760

Balloon payments						$	–		$	41,165		$	297,080		$	5,728		$	980,029		$	1,632,791		$	2,956,793
Principal amortization						5,240			10,640			8,707			7,091			3,247			7,042			41,967
Total consolidated debt						$	5,240		$	51,805		$	305,787		$	12,819		$	983,276		$	1,639,833		$	2,998,760

Fixed rate/hedged variable rate debt						$	5,120		$	51,565		$	229,547		$	12,819		$	983,276		$	1,360,833		$	2,643,160
Unhedged variable rate debt						120			240			76,240			–			–			279,000			355,600
Total consolidated debt						$	5,240		$	51,805		$	305,787		$	12,819		$	983,276		$	1,639,833		$	2,998,760

(1)	Represents the contractual interest rate as of the end of the period plus the impact of debt premiums/discounts and our interest rate hedge agreements. The weighted average interest rate excludes bank fees and amortization of loan fees.
(2)	Assumes we exercise our sole option to extend the stated maturity date of April 30, 2016, by six months, twice, to April 30, 2017.
(3)	Assumes we exercise our sole option to extend the stated maturity date of June 30, 2015, by one year, to June 30, 2016.
(4)	Assumes we exercise our sole option to extend the stated maturity date of January 31, 2016, by one year, to January 31, 2017.
(5)	Includes $550 million of our 4.60% unsecured senior notes payable due in April 2022, and $250,000 of our 8.00% unsecured senior convertible notes payable with a maturity date of April 15, 2014.

Summary of financial covenants under unsecured senior line of credit and unsecured senior bank term loans

Covenant Ratios (1)		Requirement
Leverage Ratio		Less than or equal to 60.0%
Fixed Charge Coverage Ratio		Greater than or equal to 1.50x
Secured Debt Ratio		Less than or equal to 40.0%
Unsecured Leverage Ratio		Less than or equal to 60.0%
Unsecured Interest Coverage Ratio		Greater than or equal to 1.75x

(1)	For a definition of the ratios used in the table above, refer to the amended unsecured senior line of credit and unsecured senior bank term loan agreements, dated as of April 30, 2012, which are filed as Exhibits 10.2, 10.3, and 10.4 to this Quarterly Report on Form 10-Q.

Summary of components of interest cost recognized on unsecured convertible notes

	8.00% Unsecured Senior Convertible Notes				3.70% Unsecured Senior Convertible Notes
	Three Months Ended				Three Months Ended
	June 30,				June 30,
	2012		2011		2012		2011
Contractual interest	$	5	$	4	$	3	$	1,905
Amortization of discount on liability component	2		2		1		1,115
Total interest cost	$	7	$	6	$	4	$	3,020

	Six Months Ended				Six Months Ended
	June 30,				June 30,
	2012		2011		2012		2011
Contractual interest	$	10	$	9	$	142	$	3,947
Amortization of discount on liability component	3		3		78		2,532
Total interest cost	$	13	$	12	$	220	$	6,479

(1) Our 3.70% unsecured senior convertible notes (“3.70% Unsecured Senior Convertible Notes”) require that upon conversion, the entire principal amount is to be settled in cash, and any excess value above the principal amount, if applicable, is to be settled in shares of our common stock. Based on the December 31, 2011, closing price of our common stock of $68.97, and the conversion price of our 3.70% Unsecured Senior Convertible Notes of $117.36 as of December 31, 2011, the if-converted value of the notes did not exceed the principal amount as of December 31, 2011, and accordingly, no shares of our common stock would have been issued if the notes had been settled on December 31, 2011.