6. DEBT OBLIGATIONS

The following table sets forth information regarding the Company’s consolidated debt obligations outstanding at March 31, 2018 and December 31, 2017 (in thousands):

	March 31, 2018			December 31, 2017			Effective Interest Rate		Maturity Date
MORTGAGE DEBT:
Two Logan Square	$	84,037		$	84,440		3.98%		May 2020
Four Tower Bridge		9,695			-		4.50%	(a)	Feb 2021
One Commerce Square		122,808			123,667		3.64%		Apr 2023
Two Commerce Square		112,000			112,000		4.51%		Apr 2023
Principal balance outstanding		328,540			320,107
Plus: fair market value premium (discount), net		(2,041	)		(2,325	)
Less: deferred financing costs		(525	)		(566	)
Mortgage indebtedness	$	325,974		$	317,216

UNSECURED DEBT
Seven-Year Term Loan - Swapped to fixed	$	250,000		$	250,000		3.72%		Oct 2022
$350.0M 3.95% Guaranteed Notes due 2023		350,000			350,000		3.87%		Feb 2023
$250.0M 4.10% Guaranteed Notes due 2024		250,000			250,000		4.33%		Oct 2024
$450.0M 3.95% Guaranteed Notes due 2027		450,000			450,000		4.03%		Nov 2027
$250.0M 4.55% Guaranteed Notes due 2029		250,000			250,000		4.60%		Oct 2029
Indenture IA (Preferred Trust I)		27,062			27,062		LIBOR + 1.25%		Mar 2035
Indenture IB (Preferred Trust I) - Swapped to fixed		25,774			25,774		3.30%		Apr 2035
Indenture II (Preferred Trust II) - Swapped to fixed		25,774			25,774		3.09%		Jul 2035
Principal balance outstanding		1,628,610			1,628,610
Plus: original issue premium (discount), net		(4,341	)		(4,423	)
Less: deferred financing costs		(10,211	)		(10,575	)
Total unsecured indebtedness	$	1,614,058		$	1,613,612
Total Debt Obligations	$	1,940,032		$	1,930,828

(a)

This loan was assumed upon acquisition of the related property on January 5, 2018. The interest rate reflects the market rate at the time of acquisition.

As of March 31, 2018 and December 31, 2017, the Company’s weighted-average effective interest rates on its mortgage notes payable were 4.05% and 4.04%, respectively.

In addition to the debt described above, the Company utilizes its four-year unsecured revolving credit facility (the “Credit Facility”) borrowings for general business purposes, including to fund costs of acquisitions, developments and redevelopments of properties, fund share repurchases and to repay from time to time other debt. The Credit Facility provides for borrowings of up to $600.0 million and the per annum variable interest rate on borrowings is LIBOR plus 1.20%. The interest rate and facility fee are subject to adjustment upon a change in the Company’s unsecured debt ratings. The Company had no borrowings under the Credit Facility as of and during either of the three-month periods ended March 31, 2018 and March 31, 2017.

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 was in compliance with all financial covenants as of March 31, 2018. Management continuously monitors the Company’s compliance with and anticipated compliance with the covenants. Certain of the covenants restrict the Company’s ability to obtain alternative sources of capital.

As of March 31, 2018, the Company’s aggregate scheduled principal payments of debt obligations, excluding amortization of discounts and premiums, are as follows (in thousands):

2018 (nine months remaining)	$	5,508
2019		7,595
2020		87,226
2021		15,143
2022		256,332
Thereafter		1,585,346
Total principal payments		1,957,150
Net unamortized premiums/(discounts)		(6,382	)
Net deferred financing costs		(10,736	)
Outstanding indebtedness	$	1,940,032