
2.	LONG-TERM DEBT AND LEASE OBLIGATIONS

Long-term debt, net consists of the following:



	December 31,
	2015		2014
	(in millions)
Revolving Credit Facility	$	—	$	—
Term Facility	—		142.5
7.75% Notes	200.0		200.0
6.625% Notes	550.0		550.0
6.25% Notes	400.0		400.0
5.125% Notes	200.0		200.0
Foreign credit facilities	38.0		38.9
Capital lease obligations	5.6		5.0
Debt	1,393.6		1,536.4
Less: Current portion of long-term debt	3.3		13.0
Long-term debt	1,390.3		1,523.4
Less: Debt issuance costs	14.6		18.8
Long-term debt, net	$	1,375.7	$	1,504.6

REVOLVING CREDIT FACILITY AND TERM FACILITY As of December 31, 2015, the revolving credit facility provided up to $523.5 million of revolving bank financing commitments through September 13, 2018. At December 31, 2015, $513.1 million was available under the revolving credit facility, which reflected a reduction of $10.4 million for standby letters of credit issued against the facility.

The credit agreement provides for a senior secured term loan A facility in an aggregate principal amount of $150.0 million (term facility). During 2015, we made principal payments of $142.5 million on our term facility, of which $135.9 million related to a voluntary election to prepay all outstanding principal, including $2.8 million that was due in the fourth quarter of 2015. Upon prepayment, we expensed $0.8 million in 2015 related to the write-off of the remaining unamortized debt issuance costs related to our term facility that we had been amortizing over the expected life of the borrowing.

We paid remaining debt issuance costs of $0.1 million in 2014 associated with the execution of amending our revolving credit facility and term facility. In 2013, we paid debt issuance costs of $6.9 million associated with the amendments and restatements of our revolving credit facility.

Borrowings under the revolving credit facility and term facility bear interest at rates based on adjusted LIBOR or an alternate base rate, plus an applicable margin. The applicable margin for LIBOR-based loans will be between 1.5% and 3.0%.

The revolving credit facility is secured on a first priority basis by all or substantially all of the assets of AAM and each guarantor under the collateral agreement dated as of November 7, 2008, as amended and restated as of September 13, 2013. In the event AAM achieves investment grade corporate credit ratings from Standard & Poor's and Moody's, AAM may elect to release all of the collateral from the liens granted pursuant to the collateral agreement, subject to notice requirements and other conditions. The revolving credit facility limits our ability to make certain investments, loans and guarantees, declare dividends or distributions on capital stock, redeem or repurchase capital stock and certain debt obligations, incur liens, incur indebtedness, enter into certain restrictive agreements, merge, make acquisitions or sell all or substantially all of our assets.

The revolving credit facility provides back-up liquidity for our foreign credit facilities. We intend to use the availability of long-term financing under the revolving credit facility to refinance any current maturities related to such debt agreements that are not otherwise refinanced on a long-term basis in their local markets, except where otherwise reclassified to current portion of long-term debt on our Consolidated Balance Sheet.

In 2013, we terminated our class C loan facility of $72.8 million, which would have matured on June 30, 2013. Upon termination, we expensed $0.5 million of unamortized debt issuance costs related to the class C facility.

9.25% NOTES In 2009, we issued $425.0 million of 9.25% senior secured notes due 2017 (9.25% Notes). The notes were issued at a discount of $5.5 million. Pursuant to the terms of our 9.25% Notes, in 2013, we voluntarily redeemed the remaining outstanding 9.25% Notes using the proceeds from the Term Facility and the issuance of the 5.125% Notes. This resulted in a principal payment of $340.0 million and $18.9 million for redemption premiums, as well as payments of accrued interest. We expensed $6.7 million in 2013 related to the write-off of the remaining unamortized debt discount and issuance costs related to our 9.25% Notes.

7.875% NOTES In 2007, we issued $300.0 million of 7.875% senior unsecured notes due 2017 (7.875% Notes). In 2013, we voluntarily purchased and redeemed $300.0 million of our 7.875% Notes, and paid accrued interest. Upon purchase and redemption, we expensed $8.5 million related to redemption premiums, $0.1 million of professional fees and unamortized debt issuance costs of $2.1 million related to this debt.

7.75% NOTES In 2011, we issued $200.0 million of 7.75% senior unsecured notes due 2019 (7.75% Notes).

6.625% NOTES In 2012, we issued $550.0 million of 6.625% senior unsecured notes due 2022 (6.625% Notes). Net proceeds from the 6.625% Notes were used to fund the purchase and redemption of $250.0 million of the outstanding 5.25% senior unsecured notes, including the payment of interest, the redemption of $42.5 million aggregate principal amount of our 9.25% Notes, certain pension obligations and for other general corporate purposes.

6.25% NOTES In 2013, we issued $400.0 million of 6.25% senior unsecured notes due 2021 (6.25% Notes). Net proceeds from the 6.25% Notes were used to fund the purchase and redemption of our 7.875% Notes and for other general corporate purposes. We paid debt issuance costs of $6.6 million in 2013 related to the 6.25% Notes.

5.125% NOTES In 2013, we issued $200.0 million of 5.125% senior unsecured notes due 2019 (5.125% Notes). Net proceeds from the 5.125% Notes were used to redeem the remaining $190.0 million outstanding under our 9.25% Notes. We paid debt issuance costs related to the 5.125% Notes of $0.2 million and $3.1 million in 2014 and 2013, respectively.

LEASES We lease certain facilities and furniture under capital leases expiring at various dates. The gross asset cost of our capital leases was $7.9 million and $6.7 million at December 31, 2015 and 2014, respectively. The net book value included in property, plant and equipment, net on the balance sheet was $5.6 million and $5.0 million at December 31, 2015 and 2014, respectively. The weighted-average interest rate on these capital lease obligations at December 31, 2015 was 7.2%.

We also lease certain manufacturing machinery and equipment, commercial office and production facilities, vehicles and other assets under operating leases expiring at various dates. In 2013 we entered into various sale-leaseback transactions for equipment to be used in production starting in 2013. We received proceeds of $24.1 million in 2013 as a result of these transactions. Future minimum payments under noncancelable operating leases are as follows: $20.4 million in 2016, $17.0 million in 2017, $9.1 million in 2018, $4.4 million in 2019, and $4.4 million in 2020. Our total expense relating to operating leases was $25.3 million, $23.6 million and $17.6 million in 2015, 2014 and 2013, respectively.

FOREIGN CREDIT FACILITIES We utilize local currency credit facilities to finance the operations of certain foreign subsidiaries. These credit facilities, some of which are guaranteed by Holdings and/or AAM, Inc., expire at various dates through July 2019. At December 31, 2015, $38.0 million was outstanding under these facilities and an additional $47.9 million was available.

DEBT MATURITIES Aggregate maturities of long-term debt are as follows (in millions):



2016	$	15.4
2017	4.8
2018	18.0
2019	403.1
2020	0.7
Thereafter	951.6
Total	$	1,393.6

INTEREST EXPENSE AND INVESTMENT INCOME Interest expense was $99.2 million in 2015, $99.9 million in 2014 and $115.9 million in 2013. The decrease in interest expense in 2014 as compared to 2013 is primarily due to the decrease in our weighted-average interest rate for the full year 2014 as compared to full year 2013. The decrease is also driven by lower average outstanding borrowings in 2014 as compared to 2013.

We capitalized interest of $4.5 million in 2015, $5.8 million in 2014 and $6.6 million in 2013. The weighted-average interest rate of our long-term debt outstanding at December 31, 2015 was 6.5% as compared to 6.4% and 6.3% at December 31, 2014 and 2013, respectively.

Investment income was $2.6 million in 2015 as compared to $2.1 million and $0.6 million in 2014 and 2013, respectively. Investment income includes interest earned on cash and cash equivalents and realized and unrealized gains and losses on our short-term investments during the period.