6. Indebtedness

The following table discloses certain information regarding our indebtedness:



	Outstanding Balance at						Interest Rate at December 31, 2013	Effective Interest Rate at Issuance	Maturity Date
	December 31, 2013			December 31, 2012			Interest Rate at December 31, 2013	Effective Interest Rate at Issuance	Maturity Date
Mortgage Loans Payable, Net	$	677,890		$	763,616		4.03% – 8.26%	4.03% – 8.26%	October 2014 – September 2022
Unamortized Premiums	(115		)	(161		)
Mortgage Loans Payable, Gross	$	677,775		$	763,455
Senior Unsecured Notes, Net
2016 Notes	$	159,566		$	159,510		5.750%	5.91%	1/15/2016
2017 Notes	54,960			55,385			7.500%	7.52%	12/1/2017
2027 Notes	6,066			6,066			7.150%	7.11%	5/15/2027
2028 Notes	31,883			55,261			7.600%	8.13%	7/15/2028
2032 Notes	10,514			11,500			7.750%	7.87%	4/15/2032
2014 Notes	81,149			79,683			6.420%	6.54%	6/1/2014
2017 II Notes	101,778			106,745			5.950%	6.37%	5/15/2017
Subtotal	$	445,916		$	474,150
Unamortized Discounts	980			2,570
Senior Unsecured Notes, Gross	$	446,896		$	476,720
Unsecured Credit Facility*	$	173,000		$	98,000		1.666%	1.666%	9/29/2017

* The maturity date may be extended an additional year at our election, subject to certain restrictions.

Mortgage Loans Payable, Net

During the year ended December 31, 2012, we originated the following mortgage loans:

Mortgage

Financing

Loan

Principal

Interest

Rate

Origination

Date

Maturity

Date

Amortization

Period

Number of

Industrial

Properties

Collateralizing

Mortgage

GLA

(In millions)

Properties

Carrying

Value at

December 31,

2012

I-VI

100,599

4.03

August 2012

September 2022

30-year

3.8

103,671

For Mortgage Financings I through VI, principal prepayments were prohibited for 12 months after loan origination, after which prepayment premiums are calculated at the greater of yield maintenance or 1% of the outstanding balance.

During the years ended December 31, 2013 and 2012, we paid off and retired prior to maturity mortgage loans payable in the amount of $72,261 and $14,112, respectively. In connection with these pay offs prior to maturity, we recognized $1,578 and $361 as loss from retirement of debt for the years ended December 31, 2013 and 2012, respectively.

As of December 31, 2013, mortgage loans payable are collateralized, and in some instances cross-collateralized, by industrial properties with a net carrying value of $826,754. We believe the Operating Partnership and the Company were in compliance with all covenants relating to mortgage loans payable as of December 31, 2013.

Senior Unsecured Notes, Net

During the years ended December 31, 2013 and 2012, we repurchased and retired the following senior unsecured notes prior to maturity:



	Principal Amount Repurchased				Purchase Price
	For the Year Ended December 31, 2013		For the Year Ended December 31, 2012		For the Year Ended December 31, 2013		For the Year Ended December 31, 2012
2014 Notes	$	—	$	9,000	$	—	$	9,439
2017 Notes	430		4,223		482		4,632
2017 II Notes	5,000		—		5,300		—
2028 Notes	23,394		69,680		26,547		72,541
2032 Notes	1,000		23,400		1,163		24,001
Total	$	29,824	$	106,303	$	33,492	$	110,613

In connection with these repurchases prior to maturity, we recognized $5,003 and $9,323 as loss from retirement of debt for the years ended December 31, 2013 and 2012, which is the difference between the repurchase price and the principal amount retired, net of the pro rata write-off of the unamortized debt issue discount, the unamortized deferred financing costs, the unamortized settlement amount of the interest rate protection agreements and the professional services fees related to the repurchases of $28, $191, $1,116 and $0 and $598, $728, $3,247 and $440, respectively.

On April 16, 2012, we paid off and retired our 2012 Notes, at maturity, in the amount of $61,829.

The indentures governing our senior unsecured notes contain certain financial covenants, including limitations on incurrence of debt and debt service coverage. We believe the Operating Partnership and the Company were in compliance with all covenants relating to senior unsecured notes as of December 31, 2013. However, these financial covenants are complex and there can be no assurance that these provisions would not be interpreted by our noteholders in a manner that could impose and cause us to incur material costs.

Unsecured Credit Facility

On July 19, 2013, we amended and restated our existing $450,000 revolving credit agreement (the "Old Credit Facility"), increasing the borrowing capacity thereunder to $625,000 (as amended and restated, the "Unsecured Credit Facility"). We may request that the borrowing capacity under the Unsecured Credit Facility be increased to $825,000, subject to certain restrictions. The amendment extended the maturity date from December 12, 2014 to September 29, 2017 with an option to extend an additional one year at our election, subject to certain restrictions. At December 31, 2013, the Unsecured Credit Facility provides for interest only payments at LIBOR plus 150 basis points. The interest rate on the Unsecured Credit Facility varies based on our leverage ratio. In the event we achieve an investment grade rating from one of certain rating agencies, the rate may be decreased at our election, based on the investment grade rating. In connection with the amendment of the Old Credit Facility, we wrote off $56 of unamortized deferred financing costs, which is included in loss from retirement of debt for the year ended December 31, 2013.

The Unsecured Credit Facility contains certain financial covenants, including limitations on incurrence of debt and debt service coverage. Under the Unsecured Credit Facility, an event of default can also occur if the lenders, in their good faith judgment, determine that a material adverse change has occurred which could prevent timely repayment or materially impair our ability to perform our obligations under the loan agreement. We believe that we were in compliance with all covenants relating to the Unsecured Credit Facility as of December 31, 2013. However, these financial covenants are complex and there can be no assurance that these provisions would not be interpreted by our lenders in a manner that could impose and cause us to incur material costs.

Indebtedness

The following is a schedule of the stated maturities and scheduled principal payments of our indebtedness, exclusive of premiums and discounts, for the next five years ending December 31, and thereafter:



	Amount
2014	$	113,321
2015	37,762
2016	272,618
2017	341,723
2018	168,341
Thereafter	363,906
Total	$	1,297,671

Fair Value

At December 31, 2013 and 2012, the fair value of our indebtedness was as follows:



	December 31, 2013				December 31, 2012
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Mortgage Loans Payable, Net	$	677,890	$	684,914	$	763,616	$	814,915
Senior Unsecured Debt, Net	445,916		482,781		474,150		516,943
Unsecured Credit Facility	173,000		173,000		98,000		98,192
Total	$	1,296,806	$	1,340,695	$	1,335,766	$	1,430,050

The fair values of our mortgage loans payable were determined by discounting the future cash flows using the current rates at which similar loans would be made based upon similar leverage levels and similar remaining maturities. The current market rates we utilized were internally estimated. The fair value of the senior unsecured debt was determined by using rates, as advised by our bankers in certain cases, that are based upon recent trades within the same series of the senior unsecured debt, recent trades for senior unsecured debt with comparable maturities, recent trades for fixed rate unsecured debt from companies with profiles similar to ours, as well as overall economic conditions. The fair value of the Unsecured Credit Facility was determined by discounting the future cash flows using current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining term, assuming no repayment until maturity. We have concluded that our determination of fair value for our mortgage loans payable, senior unsecured debt and Unsecured Credit Facility was primarily based upon Level 3 inputs.