The Company has a revolving credit facility with Bank of America and five other lenders which provides for a line of credit of up to $125 million, including a $35 million letter of credit subfacility, and a $35 million swingline subfacility. The revolving credit facility contains customary terms and conditions, including restrictions on indebtedness, dividend payments, business combinations and other related items. The revolving credit facility includes a full and unconditional guarantee by the Company's 100 percent owned domestic subsidiaries whose assets equal substantially all of the consolidated assets of the Company and its subsidiaries. Certain of the Company's minor subsidiaries are not guarantors.

On July 26, 2018, the Company entered into Amendment No. 4 to Credit Agreement (the “Amendment”). The Amendment, among other matters, replaces the existing minimum tangible net worth covenant with the following covenants: (i) when RPC’s trailing four quarter EBITDA (as calculated under the Credit Agreement) is equal to or greater than $50 million, a maximum consolidated leverage ratio of 2.50:1.00 and a minimum debt service coverage ratio of 2.00:1.00, and (ii) otherwise, a minimum tangible net worth covenant of no less than $600 million. The Amendment additionally (1) extended the Credit Agreement maturity date from January 17, 2020 to July 26, 2023, (2) eliminated any borrowing base limitations on revolving loans when RPC’s trailing four quarter EBITDA (as calculated under the Credit Agreement) is equal to or greater than $50 million, (3) reduced the commitment fees payable by RPC by 7.5 basis points at each pricing level and (4) reduced the letter of credit sublimit from $50 million to $35 million. As of March 31, 2020, the Company was in compliance with these covenants.

Revolving loans under the amended revolving credit facility bear interest at one of the following two rates at the Company’s election:

In addition, the Company pays an annual fee ranging from 0.15% to 0.25%, based on a quarterly consolidated leverage ratio calculation, on the unused portion of the credit facility.

The Company has incurred total loan origination fees and other debt related costs associated with this revolving credit facility in the aggregate of approximately $3.3 million. These costs are being amortized to interest expense over the remaining term of the loan, and the remaining net balance of $0.2 million at March 31, 2020 is classified as part of non-current other assets.

As of March 31, 2020, RPC had no outstanding borrowings under the revolving credit facility, and letters of credit outstanding relating to self-insurance programs and contract bids totaled $19.8 million; therefore, a total of $105.2 million of the facility was available.

Interest incurred, which includes facility fees on the unused portion of the revolving credit facility and the amortization of loan cost, and interest paid on the credit facility were as follows for the periods indicated:

Three months ended

March 31,

(in thousands)

Interest incurred

Interest paid