8. Indebtedness and Derivative Financial Instruments

Our mortgages and unsecured indebtedness, excluding the impact of derivative instruments, consist of the following as of December 31:


	2016		2015
Fixed-Rate Debt:
Mortgage notes, including $21,916 and $44,594 net premiums and $15,965 and $11,225 debt issuance costs respectively. Weighted average interest and maturity of 4.15% and 7.0 years at December 31, 2016.	$	5,876,831	$	5,974,202
Unsecured notes, including $46,426 and $44,698 net discounts and $65,801 and $52,749 debt issuance costs, respectively. Weighted average interest and maturity of 3.37% and 8.2 years at December 31, 2016.		15,252,834		13,477,678
Commercial Paper (see below)		953,665		878,657
Total Fixed-Rate Debt		22,083,330		20,330,537
Variable-Rate Debt:
Mortgages notes, including $690 and $913 debt issuance costs respectively. Weighted average interest and maturity of 2.10% and 2.8 years at December 31, 2016.		592,655		629,087
Unsecured Term Loan (see below), including $0 and $46 debt issuance costs respectively at December 31, 2016.		—		239,954
Credit Facility (see below), including $15,380 and $20,558 debt issuance costs respectively at December 31, 2016.		301,119		1,217,104
Total Variable-Rate Debt		893,774		2,086,145
Total Mortgages and Unsecured Indebtedness	$	22,977,104	$	22,416,682

General. Our unsecured debt agreements contain financial covenants and other non‑financial covenants. If we were to fail to comply with these covenants, after the expiration of the applicable cure periods, the debt maturity could be accelerated or other remedies could be sought by the lender, including adjustments to the applicable interest rate. As of December 31, 2016, we were in compliance with all covenants of our unsecured debt.

At December 31, 2016, we or our subsidiaries were the borrowers under 45 non‑recourse mortgage notes secured by mortgages on 48 properties, including two separate pools of cross‑defaulted and cross‑collateralized mortgages encumbering a total of five properties. Under these cross‑default provisions, a default under any mortgage included in the cross‑defaulted pool may constitute a default under all mortgages within that pool and may lead to acceleration of the indebtedness due on each property within the pool. Certain of our secured debt instruments contain financial and other non‑financial covenants which are specific to the properties which serve as collateral for that debt. If the applicable borrower under these non-recourse mortgage notes fails to comply with these covenants, the lender could accelerate the debt and enforce its right against their collateral. At December 31, 2016, the applicable borrowers under these non‑recourse mortgage notes were in compliance with all covenants where non‑compliance could individually, or giving effect to applicable cross‑default provisions in the aggregate, have a material adverse effect on our financial condition, liquidity or results of operations.

Unsecured Debt

At December 31, 2016, our unsecured debt consisted of $15.4 billion of senior unsecured notes of the Operating Partnership, $316.5 million outstanding under the Operating Partnership’s $3.5 billion supplemental unsecured revolving credit facility, or Supplemental Facility, and $953.7 million outstanding under the Operating Partnership’s global unsecured commercial paper program, or Commercial Paper program. The December 31, 2016 balance on the Credit Facility included $191.5 million (U.S. dollar equivalent) of Yen-denominated borrowings. At December 31, 2016, the outstanding amount under the Commercial Paper program was $953.7 million, of which $79.3 million was related to the U.S. dollar equivalent of Euro-denominated notes. Foreign currency denominated borrowings under both the Supplemental Facility and Commercial Paper program are designated as net investment hedges of a portion of our international investments.

On December 31, 2016, we had an aggregate available borrowing capacity of $6.2 billion under the Supplemental Facility and the Operating Partnership’s $4.0 billion unsecured revolving credit facility, or Credit Facility, and together with the Supplemental Facility, the Credit Facilities. The maximum aggregate outstanding balance under the Credit Facilities during the year ended December 31, 2016 was $1.5 billion and the weighted average outstanding balance was $596.4 million. Letters of credit of $18.8 million were outstanding under the Credit Facilities as of December 31, 2016.

The Credit Facility’s initial borrowing capacity of $4.0 billion may be increased to $5.0 billion during its term and provides for borrowings denominated in U.S. dollars, Euros, Yen, Sterling, Canadian dollars and Australian dollars. Borrowings in currencies other than the U.S. dollar are limited to 75% of the maximum revolving credit amount, as defined. The initial maturity date of the Credit Facility is June 30, 2018 and can be extended for an additional year to June 30, 2019 at our sole option, subject to our continued compliance with the terms thereof. The base interest rate on the Credit Facility is LIBOR plus 80 basis points with an additional facility fee of 10 basis points.

On April 6, 2016, the Operating Partnership amended the Supplemental Facility to, among other matters, (i) exercise its $750.0 million accordion feature such that the Supplemental Facility’s borrowing capacity has been increased from $2.75 billion to $3.50 billion and (ii) add a new $750.0 million accordion feature to permit us to further increase the Supplemental Facility’s borrowing capacity to $4.25 billion during its term. The initial maturity date of the Supplemental Facility is June 30, 2019 and can be extended for an additional year to June 30, 2020 at our sole option, subject to our continued compliance with the terms thereof. The base interest rate on the amended Supplemental Facility is LIBOR plus 80 basis points with an additional facility fee of 10 basis points. The Supplemental Facility provides for borrowings denominated in U.S. dollars, Euros, Yen, Sterling, Canadian dollars and Australian dollars.

The Operating Partnership also has available a Commercial Paper program of $1.0 billion, or the non-U.S. dollar equivalent thereof. The Operating Partnership may issue unsecured commercial paper notes, denominated in U.S. dollars, Euros and other currencies. Notes issued in non-U.S. currencies may be issued by one or more subsidiaries of the Operating Partnership and are guaranteed by the Operating Partnership. Notes will be sold under customary terms in the U.S. and Euro commercial paper note markets and rank (either by themselves or as a result of the guarantee described above) pari passu with the Operating Partnership's other unsecured senior indebtedness. The Commercial Paper program is supported by the Credit Facilities and if necessary or appropriate, we may make one or more draws under either of the Credit Facilities to pay amounts outstanding from time to time on the Commercial Paper program. On December 31, 2016, we had $953.7 million outstanding under the Commercial Paper program, comprised of $874.4 million outstanding in U.S. dollar denominated notes and $79.3 million (U.S. dollar equivalent) of Euro denominated notes with weighted average interest rates of 0.83% and -0.25%, respectively. The borrowings mature on various dates from January 3, 2017 to June 16, 2017 and reduce amounts otherwise available under the Credit Facilities.

On January 13, 2016, the Operating Partnership issued $550.0 million of senior unsecured notes at a fixed interest rate of 2.50% with a maturity date of July 15, 2021 and $800.0 million of senior unsecured notes at a fixed interest rate of 3.30% with a maturity date of January 15, 2026. Proceeds from the unsecured notes offering were used to pay down the Credit Facility, unencumber three properties and redeem senior unsecured notes at par in February 2016.

On May 13, 2016, a wholly-owned subsidiary of the Operating Partnership issued ‎€500.0 million ($566.7 million U.S. dollar equivalent) of senior unsecured notes at a fixed interest rate of 1.25% with a maturity date of May 13, 2025. Proceeds from the unsecured notes offering were used to pay down the Euro-denominated borrowings on the Credit Facilities and to repay at maturity the Euro-denominated borrowings under the Commercial Paper program, and for general corporate purposes.

On November 23, 2016, the Operating Partnership issued $550.0 million of senior unsecured notes at a fixed interest rate of 2.35% with a maturity date of January 30, 2022, $750.0 million of senior unsecured notes at a fixed interest rate of 3.25% with a maturity date of November 30, 2026 and $550.0 million of senior unsecured notes at a fixed interest rate of 4.25% with a maturity date of November 30, 2046. Proceeds from the unsecured notes offering were used to pay down the Supplemental Facility, to redeem senior unsecured notes at par in December 2016 and for the early redemption of senior unsecured notes in December 2016.

During 2016, the Operating Partnership repaid a $240.0 million unsecured term loan, redeemed at par or repaid at maturity $1.2 billion of senior unsecured notes with fixed interest rates ranging from 2.80% to 6.10% and completed the early redemption of a series of senior unsecured notes comprising $650.0 million with a fixed interest rate of 10.35%. We recorded a $136.8 million loss on extinguishment of debt in the fourth quarter of 2016 as a result of the early redemption.

Mortgage Debt

Total mortgage indebtedness was $6.5 billion and $6.6 billion at December 31, 2016 and 2015, respectively.

During the year ended December 31, 2016, we repaid $638.9 million in mortgage loans, with a weighted average interest rate of 7.03%, unencumbering six properties.

On January 1, 2016, as discussed in Note 7, we consolidated the European investee that held our interests in six Designer Outlet properties, as we gained control of the entity. This resulted in the consolidation of two of the six operating properties – Parndorf Designer Outlet and Roermond Designer Outlet, subject to existing acquisition date EURIBOR-based variable mortgage loans of $100.6 million and $196.8 million, respectively (both amounts U.S. dollar equivalents). The loans mature on May 25, 2022 and December 18, 2021 and bear interest at 1.90% and 1.88%, respectively.

On July 25, 2016, as discussed in Note 7, this European investee also acquired the remaining 33% interest in two Italian outlet centers in Naples and Venice as well as the remaining interests in related expansion projects. This resulted in the consolidation of these two properties – La Reggia Designer Outlet and Venice Designer Outlet, subject to existing acquisition date EURIBOR-based variable rate mortgage loans of $62.1 million and $89.0 million, respectively (both amounts U.S. dollar equivalents). The loans mature on March 31, 2027 and June 30, 2020, respectively, and bear interest at 1.13% and 1.68%, respectively.

Debt Maturity and Other

Our scheduled principal repayments on indebtedness as of December 31, 2016 are as follows:


2017	$	2,233,249
2018		802,806
2019		742,323
2020		3,563,396
2021		2,740,755
Thereafter		13,016,921
Total principal maturities		23,099,450
Net unamortized debt discount		(24,510)
Debt issuance costs, net		(97,836)
Total mortgages and unsecured indebtedness	$	22,977,104

Our cash paid for interest in each period, net of any amounts capitalized, was as follows:


	For the Year Ended December 31,
	2016		2015		2014
Cash paid for interest	$	887,118	$	943,683	$	1,018,911

Derivative Financial Instruments

Our exposure to market risk due to changes in interest rates primarily relates to our long‑term debt obligations. We manage exposure to interest rate market risk through our risk management strategy by a combination of interest rate protection agreements to effectively fix or cap a portion of variable rate debt. We are also exposed to foreign currency risk on financings of certain foreign operations. Our intent is to offset gains and losses that occur on the underlying exposures, with gains and losses on the derivative contracts hedging these exposures. We do not enter into either interest rate protection or foreign currency rate protection agreements for speculative purposes.

We may enter into treasury lock agreements as part of an anticipated debt issuance. Upon completion of the debt issuance, the fair value of these instruments is recorded as part of accumulated other comprehensive income (loss) and is amortized to interest expense over the life of the debt agreement.

The unamortized loss on our treasury locks and terminated hedges recorded in accumulated other comprehensive income (loss) was $35.4 million and $60.8 million as of December 31, 2016 and 2015, respectively. As of December 31, 2016, our outstanding LIBOR based derivative contracts consisted of an interest rate swap agreement with a notional amount of $250.0 million. As of December 31, 2015, we had no outstanding interest rate derivatives.

Within the next year, we expect to reclassify to earnings approximately $9.2 million of losses related to terminated interest rate swaps from the current balance held in accumulated other comprehensive income (loss).

Debt Issuance Costs

Our debt issuance costs consist primarily of financing fees we incurred in order to obtain long-term financing. We record amortization of debt issuance costs on a straight-line basis over the terms of the respective loans or agreements. Details of those debt issuance costs as of December 31 are as follows:


	2016		2015
Debt issuance costs	$	166,041	$	137,876
Accumulated amortization		(68,205)		(52,385)
Debt issuance costs, net	$	97,836	$	85,491

We report amortization of debt issuance costs, amortization of premiums, and accretion of discounts as part of interest expense. We amortize debt premiums and discounts, which are included in mortgages and unsecured indebtedness, over the remaining terms of the related debt instruments. These debt premiums or discounts arise either at the time of the debt issuance or as part of purchase accounting for the fair value of debt assumed in acquisitions. The accompanying consolidated statements of operations and comprehensive income include amortization from continuing operations as follows:


		For the Year Ended December 31,
	2016		2015		2014
Amortization of debt issuance costs	$	21,703	$	19,349	$	21,392
Amortization of debt premiums, net discounts		(14,583)		(16,107)		(24,092)

Fair Value of Debt

The carrying value of our variable‑rate mortgages and other loans approximates their fair values. We estimate the fair values of consolidated fixed‑rate mortgages using cash flows discounted at current borrowing rates and other indebtedness using cash flows discounted at current market rates. We estimate the fair values of consolidated fixed‑rate unsecured notes using quoted market prices, or, if no quoted market prices are available, we use quoted market prices for securities with similar terms and maturities. The book value of our consolidated fixed‑rate mortgages and unsecured indebtedness including commercial paper was $22.1 billion and $20.4 billion as of December 31, 2016 and 2015, respectively. The fair values of these financial instruments and the related discount rate assumptions as of December 31 are summarized as follows:



	2016			2015
Fair value of fixed-rate mortgages and unsecured indebtedness	$	22,703		$	21,331
Weighted average discount rates assumed in calculation of fair value for fixed-rate mortgages		4.12	%		3.46	%
Weighted average discount rates assumed in calculation of fair value for unsecured indebtedness		3.83	%		3.59	%