(4) Long-term Debt

Long-term debt is comprised of the following:

	As of December 31,
	2013			2014
	(In thousands)
Bank credit facility	$	210,000		$	375,000
7³/₄% senior notes due 2019		300,000			400,000
Premium related to 7³/₄% senior notes due 2019		—			4,984
9¹/₂% senior notes due 2020		300,000			300,000
Discount related to 9¹/₂% senior notes due 2020		(11,300	)		(9,539	)
	$	798,700		$	1,070,445

The premium and discount on the senior notes are being amortized over the life of the senior notes using the effective interest rate method.

The following table summarizes Comstock's debt as of December 31, 2014 by year of maturity:

	2015		2016		2017		2018		2019		Thereafter		Total
	(In thousands)
Bank credit facility	$	—	$	—	$	—	$	375,000	$	—	$	—	$	375,000
7³/₄% senior notes		—		—		—		—		404,984		—		404,984
9¹/₂% senior notes		—		—		—		—		—		290,461		290,461
	$	—	$	—	$	—	$	375,000	$	404,984	$	290,461	$	1,070,445

Comstock has a $1.0 billion bank credit facility with Bank of Montreal, as the administrative agent. The bank credit facility is a five year revolving credit commitment that matures on November 22, 2018. Indebtedness under the bank credit facility is secured by all of Comstock's assets and is guaranteed by all of its wholly owned subsidiaries. The credit facility is subject to borrowing base availability, which is redetermined semiannually based on the banks' estimates of the Company's future net cash flows of oil and natural gas properties. As of December 31, 2014, the borrowing base was $675.0 million, of which $300.0 million was available. The borrowing base may be affected by the performance of Comstock's properties and changes in oil and natural gas prices. Oil and natural gas prices used by the banks to redetermine the borrowing base in 2015 are expected to be lower than the prices used in 2014. The determination of the borrowing base is at the sole discretion of the administrative agent and the bank group.

Borrowings under the bank credit facility bear interest, based on the utilization of the borrowing base, at Comstock's option at either (1) LIBOR plus 1.5% to 2.5% or (2) the base rate (which is the higher of the administrative agent's prime rate, the federal funds rate plus 0.5% or 30 day LIBOR plus 1.0%) plus 0.5% to 1.5%. A commitment fee of 0.375% to 0.5%, based on the utilization of the borrowing base, is payable annually on the unused borrowing base. The bank credit facility contains covenants that, among other things, restrict the payment of cash dividends and repurchases of common stock in excess of $120.0 million per year, limit the amount of consolidated debt that Comstock may incur and limit the Company's ability to make certain loans and investments. The financial covenants under the bank credit facility consist of the maintenance of a leverage ratio which must be less than four to one and the maintenance of an interest coverage ratio which must not be less than 2.5 to one; provided, however, that the leverage ratio was recently amended such that during 2015 the maximum permitted leverage ratio is five to one. The Company was in compliance with these covenants as of December 31, 2014, and expects to remain in compliance during 2015.

Comstock has $400.0 million of 7³/₄% senior notes (the "2019 Notes") outstanding which are due on April 1, 2019 and bear interest which is payable semi-annually on each April 1 and October 1. In May 2014, the Company issued $100.0 million of the 2019 Notes in a public offering. Net proceeds from the issuance of the additional 2019 Notes of $103.3 million were used to pay down borrowings under the Company's bank credit facility. Comstock also has $300.0 million of 9¹/₂% senior notes (the "2020 Notes") which are due on June 15, 2020 and bear interest which is payable semi-annually on each June 15 and December 15. The 2019 and 2020 Notes are unsecured obligations of Comstock and are guaranteed by all of Comstock's material subsidiaries. Such subsidiary guarantors are 100% owned and all of the guarantees are full and unconditional and joint and several obligations. As of December 31, 2014, Comstock had no material assets or operations which are independent of its subsidiaries. There are no restrictions on the ability of Comstock to obtain funds from its subsidiaries through dividends or loans.

At January 1, 2013, Comstock had $300.0 million in principal amount of 8³/₈% senior notes outstanding with a maturity date of October 15, 2017 (the "2017 Notes"). In June 2013, the Company repurchased $2.2 million in principal amount of the 2017 Notes at 103.3% of the par value and in September 2013, the Company called all of the remaining 2017 Notes at the call price of 104.2% of par value for redemption on October 15, 2013. The redemption amount of $310.2 million was funded with cash on hand of $210.2 million and borrowings under the Company's bank credit facility. As a result of this redemption, the Company realized a loss on early extinguishment of debt, before income taxes, of approximately $17.9 million comprised of the premium paid for the redemption, the costs incurred related to the redemption and the write-off of unamortized debt issuance costs, including original issuance discount.