Note 8. Indebtedness

At December 31, 2015 and 2014, our outstanding indebtedness consisted of the following:


	December 31,		December 31,
	2015		2014

Unsecured revolving credit facility, due in 2019	$	117,000	$	—
Unsecured term loan, due in 2020		300,000		300,000
Unsecured term loan, due in 2022		250,000		250,000
Senior unsecured notes, 3.75% interest rate, including unamortized discounts of $2,019 and $2,577,
respectively, due in 2019		347,981		347,423
Mortgage note payable, 5.55% interest rate, including unamortized premiums of $441 and $2,167,
respectively, due in 2016(1) (2)		83,441		85,167
Mortgage note payable, 6.21% interest rate, due in 2016(1) (3)		23,499		23,833
Mortgage note payable, 5.88% interest rate, due in 2021(1)		14,160		14,374
Mortgage note payable, 7.00% interest rate, including unamortized premiums of $470 and $605,
respectively, due in 2019(1)		9,199		9,563
Mortgage note payable, 8.15% interest rate, including unamortized premiums of $292 and $398,
respectively, due in 2021(1)		6,344		7,339
Mortgage note payable, 5.73% interest rate, including unamortized premiums of $0 and $177,
respectively, due in 2015(1)(4)		—		47,418
	$	1,151,624	$	1,085,117

⁽¹⁾

We assumed these mortgages in connection with our acquisitions of certain properties. The stated interest rates for these mortgage debts are the contractually stated rates. We recorded the assumed mortgages at estimated fair value on the date of acquisition and we are amortizing the fair value premiums, if any, to interest expense over the respective terms of the mortgages to reduce interest expense to the estimated market interest rates as of the date of acquisition.

⁽²⁾

We gave notice in January 2016 to repay this mortgage at par in March 2016.

⁽³⁾

This mortgage was repaid at par in February 2016.

⁽⁴⁾

This mortgage was repaid at par in July 2015.

Our $750,000 unsecured revolving credit facility, our $300,000 term loan and our $250,000 term loan are governed by a credit agreement with a syndicate of institutional lenders that includes a number of features common to all of these credit arrangements. This credit agreement also includes a feature under which the maximum aggregate borrowing availability may be increased to up to $2,500,000 on a combined basis in certain circumstances.

Our $750,000 unsecured revolving credit facility is available for general business purposes, including acquisitions. The maturity date of our unsecured revolving credit facility is January 31, 2019 and, subject to the payment of an extension fee and meeting certain other conditions, we have an option to extend the stated maturity date of our unsecured revolving credit facility by one year to January 31, 2020. We are required to pay interest at a rate of LIBOR plus a premium, which was 125 basis points per annum at December 31, 2015 on borrowings under our unsecured revolving credit facility. We also pay a facility fee on the total amount of lending commitments under our unsecured revolving credit facility, which was 25 basis points per annum at December 31, 2015. Both the interest rate premium and the facility fee are subject to adjustment based upon changes to our credit ratings. As of December 31, 2015, the annual interest rate payable was 1.6%. The weighted average annual interest rate for borrowings under our unsecured revolving credit facility was 1.5%, 1.7% and 1.7%, respectively, for the years ended December 31, 2015, 2014 and 2013. As of December 31, 2015 and February 16, 2015, we had $117,000 and $221,000 outstanding under our unsecured revolving credit facility, respectively.

Our $300,000 unsecured term loan, which matures on March 31, 2020, is prepayable without penalty at any time. We are required to pay interest at a rate of LIBOR plus a premium, which was 140 basis points per annum at December 31, 2015 on the amount outstanding under our $300,000 term loan. The interest rate premium is subject to adjustment based upon changes to our credit ratings. As of December 31, 2015, the annual interest rate for the amount outstanding under our $300,000 term loan was 1.8%. The weighted average annual interest rate under our $300,000 term loan was 1.6% for the year ended December 31,2015 and 1.9% for the period from November 21, 2014, the date we entered into the credit agreement, to December 31, 2014.

Our $250,000 unsecured term loan, which matures on March 31, 2022, is prepayable at any time. If our $250,000 term loan is repaid on or prior to November 21, 2016, a prepayment premium of 1.0% of the amount repaid will be payable. Subsequent to November 21, 2016, no prepayment premium will be payable. We are required to pay interest at a rate of LIBOR plus a premium, which was 180 basis points per annum as of December 31, 2015 on the amount outstanding under our $250,000 term loan. The interest rate premium is subject to adjustment based upon changes to our credit ratings. As of December 31, 2015, the annual interest rate for the amount outstanding under our $250,000 term loan was 2.2%. The weighted average annual interest rate under our $250,000 term loan was 2.0% for the year ended December 31, 2015 and 2.3% for the period from November 21, 2014, the date we entered into the credit agreement, to December 31, 2014.

Our $350,000 of 3.75% senior unsecured notes due in 2019 are governed by an indenture and a supplement to the indenture, and require semi-annual payments of interest only through maturity. The outstanding amount of these notes may be prepaid at par (plus accrued and unpaid interest) on or after July 15, 2019 or before that date together with a make whole premium.

Our credit agreement and senior unsecured notes indenture and its supplement provide for acceleration of payment of all amounts due thereunder upon the occurrence and continuation of certain events of default, such as, in the case of our credit agreement, a change of control of us, which includes RMR LLC ceasing to act as our business manager and property manager. Our senior unsecured notes indenture and its supplement and our credit agreement also contain a number of covenants, including covenants that restrict our ability to incur debts, require us to maintain certain financial ratios and, in the case of our credit agreement, restrict our ability to make distributions under certain circumstances. We believe we were in compliance with the terms and conditions of the respective covenants under our senior unsecured notes indenture and its supplement and our credit agreement at December 31, 2015.

In July 2015, we repaid, at par, a $47,083 mortgage note requiring interest at 5.73% which was secured by a property (two buildings) located in Indianapolis, IN with cash on hand and borrowings under our unsecured revolving credit facility. This mortgage note was scheduled to mature in October 2015. As a result of this repayment, we recorded a gain on extinguishment of debt of $34 for the year ended December 31, 2015, which represented the unamortized debt premium and deferred finance fees related to this note.

In January 2016, we gave notice to repay, at par, an $83,000 mortgage note requiring interest at 5.55% which is secured by one office property (two buildings) located in Reston, VA. We expect to repay this mortgage note in March 2016. This mortgage note is scheduled to mature in April 2016.

In February 2016, we repaid, at par, a $23,473 mortgage note requiring interest at 6.21% which was secured by a property (one building) located in Landover, MD. This mortgage note was scheduled to mature in August 2016.

At December 31, 2015, five of our properties (six buildings) with an aggregate net book value of $198,685 secured five mortgage notes that were assumed in connection with the acquisition of such properties. Our mortgage notes are non-recourse, subject to certain limited exceptions, and do not contain any material financial covenants.