As a result of the exchange of the principal on the senior secured notes and certain royalty rights for shares of our common stock, we wrote off $18.6 million of principal associated with the senior secured notes, $1.5 million of the remaining unamortized debt discount associated with the senior secured notes, and the full carrying value of $11.5 million associated with royalty rights obligation. We recorded a gain of approximately $0.3 million during the period ending September 30, 2021 as a result of the extinguishment, representing the difference between the carrying value of the debt exchanged and the value of the shares converted based on the conversion price. As of the September 30, 2021 and following the completion of the Merger, there is approximately $43.125 million of principal (including principal of $3.125 million in respect of the PIK Note), plus accrued interest, outstanding under the senior secured notes.
The senior secured notes bear interest at 12.5% and specify semiannual payments on March 1 and September 1 and have a maturity date of March 1, 2025. The first two years provide for interest-only payments with principal payments beginning in 2022. The senior secured notes are governed by an indenture, dated as of March 12, 2020, between Old Clarus and the investors. The interest rate will increase to 14.50% for overdue installments in the event of default. In addition to liquidation preference, the senior secured notes contain a lien on all assets of Old Clarus.
The senior secured notes had a detachable royalty feature under which the lenders were to receive a royalty of 0.56% to 1.67% on net sales beginning in 2021, with the royalty obligation continuing until the lenders receive total royalty payments of approximately $24.2 million. The value assigned to royalty rights was recorded as a debt discount to the Notes and is amortized to interest expense over the life of the notes. For the three months ended September 30, 2021 and 2020, we recorded $0.7 million and $0.6 million, respectively, of interest expense associated with the royalty rights. For the nine months ended September 30, 2021 and 2020 we recorded $2.2 million and $1.4 million, respectively, of interest expense associated with the royalty rights. The royalty obligation had a fair value of $7.9 million at issuance in March of 2020. Pursuant to the Merger Agreement and conversion terms, no royalty obligation exists as of September 30, 2021.
During the three months ended September 30, 2021 and 2020, we recorded $2.6 million and $2.1 million, respectively in interest expense on the senior secured notes, of which $0.7 million and $0.7 million, respectively, was
non-cash
interest expense associated with the amortization of the debt discount and debt issue costs. During the nine months ended September 30, 2021 and 2020, we recorded $7.2 million and $5.0 million, respectively in interest expense on the senior secured notes, of which $2.0 million and $1.5 million, respectively, was
non-cash
interest expense associated with the amortization of the debt discount and issue costs. We did not make any cash interest payments during the three and nine months ended September 30, 2021 and 2020.
Pursuant to the indenture governing the senior secured notes, Old Clarus agreed to maintain cash and cash equivalents in an amount of not less than $10.0 million, calculated as of the last day of each calendar month commencing on March 31, 2020. As of December 31, 2020, Old Clarus’ cash and cash equivalents were less than $10.0 million, resulting in a default under the indenture and the negotiation of a forbearance agreement, as noted below. In connection with the Merger, the indenture was amended to require Old Clarus to maintain a balance of not less than $8.0 million in cash and cash equivalents, calculated as of the last day of each calendar month.
We classified the full carrying value of $40.3 million related to the senior secured notes as a current liability within the September 30, 2021 balance sheet as, if we are unable to obtain funding or generate operating cash flow, we do not expect that we will be in compliance with the covenants under the senior secured notes within one year of the balance sheet date. Refer to Note 1 in the Notes to Unaudited Condensed Consolidated Financial Statements in this Quarterly Report on Form 10-Q for further disclosure related to our assessment of the ability to operate as a going concern as of September 30, 2021.
On March 17, 2021, Old Clarus entered into a forbearance agreement with noteholders in relation to the senior secured notes. Old Clarus was unable to and did not pay interest of $3.1 million due on March 1, 2021. As of March 31, 2021, Old Clarus entered into default on its senior secured notes, and in accordance with the terms of the senior secured notes, the interest increased to 14.5%.
Under the forbearance agreement, in exchange for the investors’ agreement not to exercise their rights to retrieve the funds owed, Old Clarus was required to maintain cash and cash equivalents of at least $2.5 million amongst other financial budgeting and reporting requirements until consummation of the Business Combination. Under the forbearance agreement, the forbearance period would not be terminated provided that Old Clarus, amongst other things, executed the Merger Agreement and provided financial reporting requirements by April 27, 2021.
In August 2021, Old Clarus entered into forbearance extensions with the noteholders in relation to the senior secured notes. The latest forbearance extension, entered into on August 26, 2021, extended the forbearance period through September 9, 2021, the Closing Date of the Merger.
On September 28 2021, we entered into a supplemental indenture with the noteholders in relation to the senior secured notes. The supplemental indenture extended the due date of the $3.9 million interest payment due September 1, 2021 to March 1, 2022, and further accrues interest on the past interest due amount at a rate of 18.5% per annum beginning on September 1, 2021 until paid.