b'KOSMOS ENERGY LTD.Notes to Consolidated Financial Statements (Continued)8. Debt (Continued)and, equal to 20% per annum of the then-applicable respective margin when a commitment is notavailable for utilization. We recognize interest expense in accordance with ASC 835Interest, whichrequires interest expense to be recognized using the effective interest method. We determined theeffective interest rate based on the estimated level of borrowings under the Facility.The Facility provides a revolving credit and letter of credit facility. The availability period for therevolving credit facility, as amended in February 2018 expires one month prior to the final maturitydate. The letter of credit facility expires on the final maturity date. The available facility amount issubject to borrowing base constraints and, beginning on March 31, 2022, outstanding borrowings will beconstrained by an amortization schedule. The Facility has a final maturity date of March 31, 2025. Asof December 31, 2018, we had no letters of credit issued under the Facility.Kosmos has the right to cancel all the undrawn commitments under the amended and restatedFacility. The amount of funds available to be borrowed under the Facility, also known as the borrowingbase amount, is determined each year on March 31, as amended. The borrowing base amount is basedon the sum of the net present value of net cash flows and relevant capital expenditures reduced bycertain percentages as well as value attributable to certain assets reserves and/or resources in Ghanaand Equatorial Guinea.If an event of default exists under the Facility, the lenders can accelerate the maturity and exerciseother rights and remedies, including the enforcement of security granted pursuant to the Facility overcertain assets held by our subsidiaries. The Facility contains customary cross default provisions.We were in compliance with the financial covenants contained in the Facility as of theSeptember 30, 2018 (the most recent assessment date).Corporate RevolverIn August 2018, we amended and restated the Corporate Revolver maintaining the borrowingcapacity at $400.0 million, extending the maturity date from November 2018 to May 2022 and loweringthe margin 100 basis points to 5%. This resulted in lower commitment fees on the undrawn portion ofthe total commitments, which is 30% per annum of the respective margin. The Corporate Revolver isavailable for general corporate purposes and for oil and gas exploration, appraisal and developmentprograms. As of December 31, 2018, we have $8.9 million of net deferred financing costs related to theCorporate Revolver, which will be amortized over the remaining term. These deferred financing costsare included in the Other assets section of our consolidated balance sheets.As of December 31, 2018, borrowings under the Corporate Revolver totaled $325.0 million and theundrawn availability under the Corporate Revolver was $75.0 million.Interest is the aggregate of the applicable margin (5.0%); LIBOR; and mandatory cost (if any, asdefined in the Corporate Revolver). Interest is payable on the last day of each interest period (and, ifthe interest period is longer than six months, on the dates falling at six-month intervals after the firstday of the interest period). We pay commitment fees on the undrawn portion of the total commitments.Commitment fees for the lenders are equal to 30% per annum of the respective margin when acommitment is available for utilization.The Corporate Revolver, as amended in August 2018, expires on May 31, 2022. The availableamount is not subject to borrowing base constraints. Kosmos has the right to cancel all the undrawn129'