minority investments, (g) to the extent actually reimbursed by insurance, expenses with respect to liability on casualty events or business interruption, and (h) all reasonable transaction expenses related to dispositions and acquisitions of assets, investments and debt and equity offerings (provided that expenses related to any unsuccessful dispositions will be limited to $3.0 million in the aggregate) for a twelve-month period may not be greater than 4.00 to 1.00; and (2) the ratio of EBITDAX to interest expense for a twelve-month period may not be less than 3.00 to 1.00. We were in compliance with these financial covenants at September 30, 2017.
Senior Notes
On April 21, 2015, we issued the 2023 Notes in an aggregate principal amount of $350.0 million. The 2023 Notes were issued under an indenture, dated as of April 21, 2015, among us, our subsidiary guarantors party thereto and Wells Fargo Bank, N.A., as trustee, to qualified institutional buyers pursuant to Rule 144A under the Securities Act, and to certainnon-U.S. persons in accordance with Regulation S under the Securities Act. Interest on the 2023 Notes accrues at a rate of 6.625% per annum on the outstanding principal amount thereof, payable semi-annually on May 1 and November 1 of each year. The 2023 Notes will mature on May 1, 2023.
On October 14, 2016, we issued the 2024 Notes in aggregate principal amount of $650.0 million. The 2024 Notes were issued under an indenture, dated as of October 14, 2016, among us, the subsidiary guarantors party thereto and Wells Fargo Bank, N.A., as trustee, to qualified institutional buyers pursuant to Rule 144A under the Securities Act, and to certainnon-U.S. persons in accordance with Regulation S under the Securities Act. Interest on the 2024 Notes accrues at a rate of 6.000% per annum on the outstanding principal amount thereof from October 14, 2016, payable semi-annually on April 15 and October 15 of each year, commencing on April 15, 2017. The 2024 Notes will mature on October 15, 2024. We received approximately $638.9 million in net proceeds from the offering of the 2024 Notes, which was used, together with cash on hand, to purchase our then outstanding 7.750% Senior Notes due 2020 in a concurrent cash tender offer, to pay fees and expenses thereof, and to redeem any of such notes that remained outstanding after the completion of the tender offer.
On December 21, 2016, we issued the 2025 Notes in aggregate principal amount of $600.0 million. The 2025 Notes were issued under an indenture, dated as of December 21, 2016, among us, the subsidiary guarantors party thereto and Wells Fargo Bank, N.A., as trustee, to qualified institutional buyers pursuant to Rule 144A under the Securities Act, and to certainnon-U.S. persons in accordance with Regulation S under the Securities Act. Interest on the 2025 Notes accrues at a rate of 6.375% per annum on the outstanding principal amount thereof from December 21, 2016, payable semi-annually on May 15 and November 15 of each year, commencing on May 15, 2017. The 2025 Notes will mature on May 15, 2025. We received approximately $584.7 million in net proceeds from the offering of the 2025 Notes, which we used, together with the net proceeds from our December 2016 offering of common stock and cash on hand, to fund the cash portion of the purchase price for our acquisition of certain assets of Vitruvian II Woodford, LLC, an unrelated third-party seller.
On October 11, 2017, we issued $450.0 million in aggregate principal amount of the Initial Notes. The Initial Notes were issued under the Indenture to qualified institutional buyers pursuant to Rule 144A under the Securities Act, and to certainnon-U.S. persons in accordance with Regulation S under the Securities Act. Under the Indenture, interest on the Initial Notes accrues at a rate of 6.375% per annum on the outstanding principal amount thereof from October 11, 2017, payable semi-annually on January 15 and July 15 of each year. The first interest payment date with respect to the Initial Notes is January 15, 2018. The Initial Notes will mature on January 15, 2026. We received approximately $444.5 million in net proceeds from the offering of the Initial Notes, which we used to repay all of our outstanding borrowings under our secured revolving credit facility on October 11, 2017 and the balance was used for general corporate purposes, which included the funding of a portion of our 2017 capital development plans.
All of our existing and future restricted subsidiaries that guarantee our secured revolving credit facility or certain other debt guarantee the 2023 Notes, 2024 Notes, 2025 Notes and the Initial Notes, provided, however, that the 2023 Notes, 2024 Notes, 2025 Notes and the Initial Notes are not guaranteed by Grizzly Holdings, which
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