A summary of outstanding indebtedness of the Operating Partnership as of December 31, 2015 and 2014 is as follows (in thousands):



Indebtedness	Interest Rate at December 31, 2015		Maturity Date	Principal Outstanding December 31, 2015				Principal Outstanding December 31, 2014
Global revolving credit facility	Various	⁽¹⁾	Nov 3, 2017	$	967,884		⁽²⁾	$	525,951		⁽²⁾
Unsecured term loan	Various	⁽³⁾⁽⁹⁾	Apr 16, 2017	924,568			⁽⁴⁾	976,600			⁽⁴⁾
Unsecured senior notes:
Prudential Shelf Facility:
Series C	9.680%		Jan 6, 2016	25,000			⁽⁵⁾	25,000
Series D	4.570%		Jan 20, 2015	—				50,000
Series E	5.730%		Jan 20, 2017	50,000				50,000
Series F	4.500%		Feb 3, 2015	—				17,000
Total Prudential Shelf Facility				75,000				142,000
Senior Notes:
4.50% notes due 2015	4.500%		Jul 15, 2015	—				375,000
5.875% notes due 2020	5.875%		Feb 1, 2020	500,000				500,000
3.40% notes due 2020	3.400%		Oct 1, 2020	500,000				—
5.25% notes due 2021	5.250%		Mar 15, 2021	400,000				400,000
3.95% notes due 2022	3.950%		Jul 1, 2022	500,000				—
3.625% notes due 2022	3.625%		Oct 1, 2022	300,000				300,000
4.75% notes due 2023	4.750%		Oct 13, 2023	442,080			⁽¹⁰⁾	467,310			⁽¹⁰⁾
4.25% notes due 2025	4.250%		Jan 17, 2025	589,440			⁽¹⁰⁾	623,080			⁽¹⁰⁾
4.75% notes due 2025	4.750%		Oct 1, 2025	450,000				—
Unamortized discounts				(17,914		)		(15,632		)
Total senior notes, net of discount				3,663,606				2,649,758
Total unsecured senior notes, net of discount				3,738,606				2,791,758


Mortgage loans:
200 Paul Avenue 1-4 (7)	5.74%		Oct 8, 2015	—				68,665
2045 & 2055 Lafayette Street (7)	5.93%		Feb 6, 2017	61,437				62,563
34551 Ardenwood Boulevard 1-4 (7)	5.95%		Nov 11, 2016	50,477				51,339
1100 Space Park Drive (7)	5.89%		Dec 11, 2016	50,423				51,295
600 West Seventh Street	5.80%		Mar 15, 2016	46,000			⁽⁶⁾	47,825
150 South First Street (7)	6.30%		Feb 6, 2017	48,484				49,316
2334 Lundy Place (7)	5.96%		Nov 11, 2016	36,714				37,340
8025 North Interstate 35	4.09%		Mar 6, 2016	5,789			⁽⁸⁾	6,057
731 East Trade Street	8.22%		Jul 1, 2020	3,420				3,836
Unamortized net premiums				439				582
Total mortgage loans, including premiums				303,183				378,818
Total indebtedness				$	5,934,241			$	4,673,127

(1)

The interest rate for borrowings under the global revolving credit facility equals the applicable index plus a margin of 110 basis points, which is based on the credit rating of our long-term debt. An annual facility fee of 20 basis points, which is based on the credit rating of our long-term debt, is due and payable quarterly on the total commitment amount of the facility. Two six-month extensions are available, which we may exercise if certain conditions are met.


(2)	Balances as of December 31, 2015 and December 31, 2014 are as follows (balances, in thousands):



Denomination of Draw	Balance as of December 31, 2015			Weighted-average interest rate		Balance as of December 31, 2014			Weighted-average interest rate
Floating Rate Borrowing (a)
U.S. dollar ($)	$	274,000		1.46	%	$	90,000		1.27	%
British pound sterling (£)	95,784		(c)	1.61	%	132,716			1.61	%
Euro (€)	280,565		(c)	0.90	%	58,071		(d)	1.13	%
Australian dollar (AUD)	96,831		(c)	3.16	%	72,676		(d)	3.74	%
Hong Kong dollar (HKD)	86,082		(c)	1.33	%	79,336		(d)	1.34	%
Japanese yen (JPY)	14,304		(c)	1.15	%	13,201		(d)	1.17	%
Singapore dollar (SGD)	49,132		(c)	1.92	%	6,565			—
Canadian dollar (CAD)	71,186		(c)	1.95	%	62,386		(d)	2.39	%
Total	$	967,884		1.53	%	$	514,951		1.84	%
Base Rate Borrowing (b)
U.S. dollar ($)	$	—		—	%	$	11,000		3.35	%
Total borrowings	$	967,884		1.53	%	$	525,951		1.87	%


(a)	The interest rates for floating rate borrowings under the global revolving credit facility equal the applicable index plus a margin of 110 basis points, which is based on the credit rating of our long-term debt.


(b)	The interest rates for base rate borrowings under the global revolving credit facility equal the U.S. Prime Rate plus a margin of 10 basis points, which is based on the credit rating of our long-term debt.


(c)	Based on exchange rates of $1.47 to £1.00, $1.09 to €1.00, $0.73 to 1.00 AUD, $0.13 to 1.00 HKD, $0.01 to 1.00 JPY, $0.70 to 1.00 SGD and $0.72 to 1.00 CAD, respectively, as of December 31, 2015.


(d)	Based on exchange rates $1.56 to £1.00, of $1.21 to €1.00, $0.82 to 1.00 AUD, $0.13 to 1.00 HKD, $0.01 to 1.00 JPY, $0.75 to 1.00 SGD and $0.86 to 1.00 CAD, respectively, as of December 31, 2014.


(3)	Interest rates are based on our current senior unsecured debt ratings and are 120 basis points over the applicable index for floating rate advances. Two six-month extensions are available, which we may exercise if certain conditions are met.


(4)	Balances as of December 31, 2015 and December 31, 2014 are as follows (balances, in thousands):



Denomination of Draw	Balance as of December 31, 2015			Weighted-average interest rate			Balance as of December 31, 2014			Weighted-average interest rate
U.S. dollar ($)	$	410,905		1.51	%	(b)	$	410,905		1.36	%	(d)
Singapore dollar (SGD)	161,070		(a)	2.16	%	(b)	172,426		(c)	1.45	%	(d)
British pound sterling (£)	178,195		(a)	1.78	%		188,365		(c)	1.76	%
Euro (€)	99,061		(a)	1.00	%		120,375		(c)	1.22	%
Australian dollar (AUD)	75,337		(a)	3.27	%		84,529		(c)	3.98	%
Total	$	924,568		1.76	%	(b)	$	976,600		1.66	%	(d)


(a)	Based on exchange rates of $0.70 to 1.00 SGD, $1.47 to £1.00, $1.09 to €1.00 and $0.73 to 1.00 AUD, respectively, as of December 31, 2015.


(b)	As of December 31, 2015, the weighted-average interest rate reflecting interest rate swaps was 1.90% (U.S. dollar), 2.19% (Singapore dollar) and 1.94% (Total). See Note 14 for further discussion on interest rate swaps.


(c)	Based on exchange rates of $0.75 to 1.00 SGD, $1.56 to £1.00, $1.21 to €1.00 and $0.82 to 1.00 AUD, respectively, as of December 31, 2014.


(d)	As of December 31, 2014, the weighted-average interest rate reflecting interest rate swaps was 1.92% (U.S. dollar), 2.01% (Singapore dollar) and 2.00% (Total). See Note 14 for further discussion on interest rate swaps.


(5)	This note was paid in full at maturity in January 2016.


(6)	This mortgage loan was paid in full in February 2016.


(7)	The respective borrower’s assets and credit are not available to satisfy the debts and other obligations of affiliates or any other person.


(8)	This mortgage loan was paid in full in January 2016


(9)	We have entered into interest rate swap agreements as a cash flow hedge for interest generated by the U.S. dollar and Singapore dollar tranches of the unsecured term loan. See note 14 for further information.


(10)	Based on exchange rate of $1.47 to £1.00 as of December 31, 2015 and $1.56 to £1.00 as of December 31, 2014.