DEBT OBLIGATIONS

The following table sets forth information regarding the Company’s consolidated debt obligations outstanding at March 31, 2013 and December 31, 2012 (in thousands):



Property / Location	March 31, 2013			December 31, 2012			Effective Interest Rate			Maturity Date
MORTGAGE DEBT:
Tysons Corner	92,732			93,188			5.36	%	(a)	Aug-15
Two Logan Square	89,133			89,340			7.57	%		Apr-16
Fairview Eleven Tower	21,939			22,000			4.25	%		Jan-17
IRS Philadelphia Campus	195,608			197,111			7.00	%		Sep-30
Cira South Garage	41,765			42,303			7.12	%		Sep-30
Principal balance outstanding	441,177			443,942
Plus: fair market value premiums (discounts), net	(877		)	(968		)
Total mortgage indebtedness	$	440,300		$	442,974
UNSECURED DEBT:
Credit Facility	—			69,000			LIBOR + 1.50%			Feb-16
Three-Year Term Loan - Swapped to fixed	150,000			150,000			2.60	%		Feb-15
Four-Year Term Loan - Variable	100,000			100,000			LIBOR + 1.75%			Feb-16
Seven-Year Term Loan - Swapped to fixed	200,000			200,000			3.62	%		Feb-19
$250.0M 5.400% Guaranteed Notes due 2014	238,379			238,379			5.53	%		Nov-14
$250.0M 7.500% Guaranteed Notes due 2015	166,535			166,535			7.76	%		May-15
$250.0M 6.000% Guaranteed Notes due 2016	150,429			150,429			5.95	%		Apr-16
$300.0M 5.700% Guaranteed Notes due 2017	300,000			300,000			5.68	%		May-17
$325.0M 4.950% Guaranteed Notes due 2018	325,000			325,000			5.13	%		Apr-18
$250.0M 3.950% Guaranteed Notes due 2023	250,000			250,000			4.02	%		Feb-23
Indenture IA (Preferred Trust I)	27,062			27,062			2.75	%		Mar-35
Indenture IB (Preferred Trust I)	25,774			25,774			3.30	%		Apr-35
Indenture II (Preferred Trust II)	25,774			25,774			3.09	%		Jul-35
Principal balance outstanding	1,958,953			2,027,953
plus: original issue premium (discount), net	(5,321		)	(5,597		)
Total unsecured indebtedness	$	1,953,632		$	2,022,356
Total Debt Obligations	$	2,393,932		$	2,465,330


(a)	This loan was assumed upon acquisition of the property that secures the mortgage debt. The interest rate reflects the market rate at the time of acquisition.

During the three-month periods ended March 31, 2013 and 2012, the Company’s weighted-average effective interest rate on its mortgage notes payable was 6.65% and 6.72%, respectively.

The Parent Company unconditionally guarantees the unsecured debt obligations of the Operating Partnership (or is a co-borrower with the Operating Partnership) but does not by itself incur unsecured indebtedness. The Parent Company has no material assets other than its investment in the Operating Partnership.

The Company utilizes its unsecured revolving credit facility (the "Credit Facility") for general business purposes, including to fund costs of acquisitions, developments and redevelopments and repayment of other debt. The scheduled maturity date of the Credit Facility in place at March 31, 2013 is February 1, 2016. The per annum variable interest rate on balances outstanding under the Credit Facility is LIBOR plus 1.50%. The interest rate and facility fee are subject to adjustment upon a change in the Company’s unsecured debt ratings. As of March 31, 2013, the Company did not have any outstanding borrowings on its Credit Facility, with $0.9 million in letters of credit outstanding, leaving $599.1 million of unused availability under the Credit Facility. During each of the three-month periods ended March 31, 2013 and 2012, there were no weighted-average interest rates associated with the Credit Facility because there were no borrowings outstanding under the Credit Facility during either period.

The Company has the option to increase the amounts available to be advanced under the Credit Facility, the $150.0 million three-year term loan, and the $100.0 million four-year term loan by an aggregate of $200.0 million, subject to customary conditions and limitations, by obtaining additional commitments from the current lenders and other financial institutions. The Company also has the option to extend the maturity dates of each of the Credit Facility, the $150.0 million three-year term loan and the $100.0 million four-year term loan by one year, subject to payment of an extension fee and other customary conditions and limitations. The Company may repay the $150.0 million three-year term loan and the $100.0 million four-year term loan at any time without penalty. The $200.0 million seven-year term loan is subject to a declining prepayment penalty (3.00% commencing one year after closing, 2.00% after two years, 1.00% after three years and without penalty thereafter).

The spread to LIBOR for LIBOR-based loans under the Credit Facility and term loans depends on the Company's unsecured senior debt credit rating. Based on the Company's current credit rating, the spread for such loans will be 150 basis points under the Credit Facility, 175 basis points under both the $150.0 million three-year term loan and the $100.0 million four-year term loan and 190 basis points under the $200.0 million seven-year term loan. At the Company's option, advances under the Credit Facility and term loans may also bear interest at a per annum floating rate equal to the higher of the prime rate or the federal funds rate plus 0.50% per annum. The Credit Facility contains a competitive bid option that allows banks that are part of the lender consortium to bid to make loans to the Company at a reduced rate. The Company executed hedging transactions that fix the rate on the $200.0 million seven-year term loan at a 3.623% average rate for its full term, and the rate on the $150.0 million three-year term loan at a 2.596% average rate for periods of three to four years. All hedges commenced on February 1, 2012 and the rates are inclusive of the LIBOR spread based on the Company's current investment grade rating. See Note 9 for details of the interest rate swaps entered into as of March 31, 2013.

The Credit Facility and term loans contain financial and operating covenants and restrictions. The Company was in compliance with all such restrictions and financial covenants as of March 31, 2013.

As of March 31, 2013, the Company’s aggregate scheduled principal payments on debt obligations, excluding amortization of discounts and premiums, were as follows (in thousands):



2013	$	8,473
2014	250,321
2015	416,568
2016	347,038
2017	330,323
Thereafter	1,047,407
Total principal payments	2,400,130
Net unamortized premiums/(discounts)	(6,198		)
Outstanding indebtedness	$	2,393,932