4. Long-Term Debt

Senior Secured Credit Facility

On August 16, 2018, the Company entered into a $1.25 billion senior secured credit facility, or the 2018 Credit Facility, consisting of a $250.0 million term loan A, or the 2018 Term Loan A, a $750.0 million term loan B, or the 2018 Term Loan B, and a $250.0 million revolving credit facility, or the 2018 Revolving Credit Facility, with a syndicate of financial institutions as lenders. The 2018 Term Loan B matures upon the earlier of: (i) August 18, 2025; or (ii) December 15, 2023 if the outstanding principal on the 2024 Convertible Notes, as defined below, exceeds $350.0 million and the Company exceeds certain leverage ratios as of that date. All obligations under the 2018 Credit Facility are unconditionally guaranteed by certain direct and indirect wholly-owned subsidiaries of Herbalife Nutrition Ltd. and secured by the equity interests of certain of Herbalife Nutrition Ltd.’s subsidiaries and substantially all of the assets of the domestic loan parties. Also on August 16, 2018, the Company issued $400.0 million aggregate principal amount of senior unsecured notes, or the 2026 Notes as described below, and used the proceeds from the 2018 Credit Facility and the 2026 Notes to repay in full the $1,178.1 million outstanding under the Company's prior senior secured credit facility.

The 2018 Term Loan B was issued to the lenders at a 0.25% discount, or $1.9 million. The Company incurred approximately $11.7 million of debt issuance costs in connection with the 2018 Credit Facility. The discount and debt issuance costs are recorded on the Company’s condensed consolidated balance sheet and are being amortized over the life of the 2018 Credit Facility using the effective-interest method.

On December 12, 2019, the Company amended the 2018 Credit Facility which, among other things, reduced the interest rate for borrowings under the 2018 Term Loan B from either the eurocurrency rate plus a margin of 3.25% or the base rate plus a margin of 2.25% to either the eurocurrency rate plus a margin of 2.75% or the base rate plus a margin of 1.75%. The Company incurred approximately $1.2 million of debt issuance costs in connection with the amendment. For accounting purposes, pursuant to FASB ASC Topic 470, Debt, or ASC 470, this transaction was accounted for as a modification of the 2018 Credit Facility. The debt issuance costs were recognized in interest expense, net within the Company’s condensed consolidated statement of income during the three months ended December 31, 2019.

On March 19, 2020, the Company amended the 2018 Credit Facility which, among other things, extended the maturity of both the 2018 Term Loan A and 2018 Revolving Credit Facility to the earlier of: (i) March 19, 2025 or (ii) September 15, 2023 if the outstanding principal on the 2024 Convertible Notes, as defined below, exceeds $350.0 million and the Company exceeds certain leverage ratios as of that date; increased borrowings under the 2018 Term Loan A from $234.4 million to a total of $264.8 million; increased the total available borrowing capacity under 2018 Revolving Credit Facility from $250.0 million to $282.5 million; and reduced the interest rate for borrowings under both the 2018 Term Loan A and 2018 Revolving Credit Facility from either the eurocurrency rate plus a margin of 3.00% or the base rate plus a margin of 2.00% to either the eurocurrency rate plus a margin of 2.50% or the base rate plus a margin of 1.50%. The Company incurred approximately $1.6 million of debt issuance costs in connection with the amendment. For accounting purposes, pursuant to ASC 470, this transaction was accounted for as a modification of the 2018 Credit Facility. Of the $1.6 million of debt issuance costs, approximately $1.1 million was recorded on the Company’s condensed consolidated balance sheet and is being amortized over the life of the 2018 Credit Facility using the effective-interest method, and approximately $0.5 million was recognized in interest expense, net within the Company’s condensed consolidated statement of income during the three months ended March 31, 2020.

On February 10, 2021, the Company amended the 2018 Credit Facility which, among other things, reduced the interest rate for borrowings under the 2018 Term Loan B from either the eurocurrency rate plus a margin of 2.75% or the base rate plus a margin of 1.75% to either the eurocurrency rate plus a margin of 2.50% or the base rate plus a margin of 1.50%. The Company incurred approximately $1.1 million of debt issuance costs in connection with the amendment. For accounting purposes, pursuant to ASC 470, this transaction was accounted for as a modification of the 2018 Credit Facility. The debt issuance costs were recognized in interest expense, net within the Company’s condensed consolidated statement of income during the three months ended March 31, 2021.

On July 30, 2021, the Company amended the 2018 Credit Facility which, among other things, increased borrowings under the 2018 Term Loan A from $245.0 million to a total of $286.2 million; increased the total available borrowing capacity under the 2018 Revolving Credit Facility from $282.5 million to $330.0 million; reduced the interest rate for borrowings under the 2018 Term Loan A and 2018 Revolving Credit Facility from either the eurocurrency rate plus a margin of 2.50% or the base rate plus a margin of 1.50% to, depending on the Company's total leverage ratio, either the eurocurrency rate plus a margin of between 1.75% and 2.25% or the base rate plus a margin of between 0.75% and 1.25%; and amended the commitment fee on the undrawn portion of the 2018 Revolving Credit Facility from 0.35% per annum to, depending on the Company's total leverage ratio, between 0.25% to 0.35% per annum. As a result of the amendment, the applicable margin for the 2018 Term Loan A and 2018 Revolving Credit Facility may also be subject to certain premiums or discounts tied to criteria determined by certain sustainability targets. The Company incurred approximately $1.4 million of debt issuance costs in connection with the amendment. For accounting purposes, pursuant to ASC 470, this transaction was accounted for as a modification of the 2018 Credit Facility. Of the $1.4 million of debt issuance costs, approximately $0.8 million was recorded on the Company’s condensed consolidated balance sheet and is being amortized over the life of the 2018 Credit Facility using the effective-interest method, and approximately $0.6 million was recognized in interest expense, net within the Company’s condensed consolidated statement of income during the three months ended September 30, 2021.

Under the 2018 Credit Facility, borrowings under both the 2018 Term Loan A and 2018 Revolving Credit Facility bear interest at, depending on the Company's total leverage ratio, either the eurocurrency rate plus a margin of between 1.75% and 2.25% or the base rate plus a margin of between 0.75% and 1.25%. The applicable margin may also be subject to certain premiums or discounts tied to criteria determined by certain sustainability targets. Borrowings under the 2018 Term Loan B bear interest at either the eurocurrency rate plus a margin of 2.50% or the base rate plus a margin of 1.50%. The eurocurrency rate is based on adjusted LIBOR and is subject to a floor of 0.00%. The base rate represents the highest of the Federal Funds Rate plus 0.50%, one-month adjusted LIBOR plus 1.00%, and the prime rate quoted by The Wall Street Journal, and is subject to a floor of 1.00%. The Company is required to pay a commitment fee on the 2018 Revolving Credit Facility of, depending on the Company's total leverage ratio, between 0.25% to 0.35% per annum on the undrawn portion of the 2018 Revolving Credit Facility. Interest is due at least quarterly on amounts outstanding under the 2018 Credit Facility.

The 2018 Credit Facility requires the Company to comply with a leverage ratio. The 2018 Credit Facility also contains affirmative and negative covenants customary for financings of this type, including, among other things, limitations or prohibitions on repurchasing common shares, declaring and paying dividends and other distributions, redeeming and repurchasing certain other indebtedness, loans and investments, additional indebtedness, liens, mergers, asset sales and transactions with affiliates. In addition, the 2018 Credit Facility contains customary events of default. As of September 30, 2021 and December 31, 2020, the Company was in compliance with its debt covenants under the 2018 Credit Facility.

The 2018 Term Loan A and 2018 Term Loan B are payable in consecutive quarterly installments which began on December 31, 2018. In addition, beginning in 2020, the Company may be required to make mandatory prepayments towards the 2018 Term Loan B based on the Company’s consolidated leverage ratio and annual excess cash flows as defined under the terms of the 2018 Credit Facility. The Company is also permitted to make voluntary prepayments. Amounts outstanding under the 2018 Term Loan A and 2018 Term Loan B may be voluntarily prepaid without premium or penalty, subject to customary breakage fees in connection with the prepayment of a eurocurrency loan. These prepayments, if any, will be applied against remaining quarterly installments owed under the 2018 Term Loan A and 2018 Term Loan B in order of maturity with the remaining principal due upon maturity, unless directed otherwise by the Company. Based on the 2020 consolidated leverage ratio and excess cash flow calculation, both as defined under the terms of the 2018 Credit Facility, the Company will not be required to make a mandatory prepayment in 2021 toward the 2018 Term Loan B.

As of September 30, 2021 and December 31, 2020, the weighted-average interest rate for borrowings under the 2018 Credit Facility was 2.65% and 3.39%, respectively.

During the nine months ended September 30, 2021, the Company borrowed an aggregate amount of $531.2 million under the 2018 Credit Facility and repaid a total amount of $415.8 million on amounts outstanding under the 2018 Credit Facility, including a $60.0 million prepayment on amounts outstanding under the 2018 Term Loan B. During the nine months ended September 30, 2020, the Company borrowed an aggregate amount of $30.4 million under the 2018 Credit Facility and repaid a total amount of $15.6 million on amounts outstanding under the 2018 Credit Facility. As of September 30, 2021 and December 31, 2020, the U.S. dollar amount outstanding under the 2018 Credit Facility was $1,100.1 million and $984.7 million, respectively. Of the $1,100.1 million outstanding under the 2018 Credit Facility as of September 30, 2021, $282.6 million was outstanding under the 2018 Term Loan A, $667.5 million was outstanding under the 2018 Term Loan B, and $150.0 million was outstanding under the 2018 Revolving Credit Facility. Of the $984.7 million outstanding under the 2018 Credit Facility as of December 31, 2020, $251.6 million was outstanding under the 2018 Term Loan A and $733.1 million was outstanding under the 2018 Term Loan B. There were no borrowings outstanding under the 2018 Revolving Credit Facility as of December 31, 2020. There were no outstanding foreign currency borrowings under the 2018 Credit Facility as of September 30, 2021 and December 31, 2020.

During the three months ended September 30, 2021 and 2020, the Company recognized $8.9 million and $8.0 million, respectively, of interest expense relating to the 2018 Credit Facility, which included $0.1 million and $0.1 million, respectively, relating to non-cash interest expense relating to the debt discount and $0.9 million and $0.5 million, respectively, relating to amortization of debt issuance costs. During the nine months ended September 30, 2021 and 2020, the Company recognized $26.1 million and $29.2 million, respectively, of interest expense relating to the 2018 Credit Facility, which included $0.3 million and $0.2 million, respectively, relating to non-cash interest expense relating to the debt discount and $1.8 million and $1.4 million, respectively, relating to amortization of debt issuance costs.

The fair value of the outstanding borrowings on the 2018 Term Loan A is determined by utilizing over-the-counter market quotes for similar instruments, which are considered Level 2 inputs as described in Note 12, Fair Value Measurements. As of September 30, 2021 and December 31, 2020, the carrying value of the 2018 Term Loan A was $281.6 million and $250.5 million, respectively, and the fair value was approximately $281.9 million and $251.9 million, respectively. The fair value of the outstanding borrowings under the 2018 Term Loan B is determined by utilizing over-the-counter market quotes, which are considered Level 2 inputs as described in Note 12, Fair Value Measurements. As of September 30, 2021 and December 31, 2020, the carrying amount of the 2018 Term Loan B was $662.0 million and $726.0 million, respectively, and the fair value was approximately $665.8 million and $734.0 million, respectively. The fair value of the outstanding borrowings on the 2018 Revolving Credit Facility approximated its carrying value of $150.0 million as of September 30, 2021 due to its variable interest rate which reprices frequently and represents floating market rates.

Convertible Senior Notes due 2024

In March 2018, the Company issued $550.0 million aggregate principal amount of convertible senior notes, or the 2024 Convertible Notes, in a private offering to qualified institutional buyers, pursuant to Rule 144A under the Securities Act of 1933, as amended. The 2024 Convertible Notes are senior unsecured obligations which rank effectively subordinate to any of the Company’s existing and future secured indebtedness, including amounts outstanding under the 2018 Credit Facility, to the extent of the value of the assets securing such indebtedness. The 2024 Convertible Notes pay interest at a rate of 2.625% per annum payable semiannually in arrears on March 15 and September 15 of each year, beginning on September 15, 2018. Unless redeemed, repurchased or converted in accordance with their terms prior to such date, the 2024 Convertible Notes mature on March 15, 2024. Holders of the 2024 Convertible Notes may convert their notes at their option under the following circumstances: (i) during any calendar quarter commencing after the calendar quarter ending June 30, 2018, if the last reported sale price of the Company’s common shares for at least 20 trading days (whether or not consecutive) in a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter exceeds 130% of the conversion price for the 2024 Convertible Notes on each applicable trading day; (ii) during the five business-day period immediately after any five consecutive trading day period, or the measurement period, in which the trading price per $1,000 principal amount of 2024 Convertible Notes for each trading day of that measurement period was less than 98% of the product of the last reported sale price of the Company’s common shares and the conversion rate for the 2024 Convertible Notes for each such day; (iii) if the Company calls the 2024 Convertible Notes for redemption; or (iv) upon the occurrence of specified corporate events. On and after December 15, 2023, holders may convert their 2024 Convertible Notes at any time, regardless of the foregoing circumstances. Upon conversion, the 2024 Convertible Notes will be settled, at the Company’s election, in cash, the Company’s common shares, or a combination thereof, based on the applicable conversion rate at such time. The 2024 Convertible Notes had an initial conversion rate of 16.0056 common shares per $1,000 principal amount of the 2024 Convertible Notes, or an initial conversion price of approximately $62.48 per common share. The conversion rate is subject to adjustment upon the occurrence of certain events and was 16.0467 common shares per $1,000 principal amount of the 2024 Convertible Notes, or a conversion price of approximately $62.32 per common share, as of September 30, 2021.

The Company incurred approximately $12.9 million of issuance costs during the first quarter of 2018 relating to the issuance of the 2024 Convertible Notes. Of the $12.9 million issuance costs incurred, $9.6 million and $3.3 million were recorded as debt issuance costs and additional paid-in capital, respectively, in proportion to the allocation of the proceeds of the 2024 Convertible Notes. The $9.6 million of debt issuance costs, which was recorded as an additional debt discount on the Company’s condensed consolidated balance sheet, are being amortized over the contractual term of the 2024 Convertible Notes using the effective-interest method.

In March 2018, the $550.0 million aggregate principal amount of the 2024 Convertible Notes were initially allocated between long-term debt, or liability component, and additional paid-in capital, or equity component, within the Company’s condensed consolidated balance sheet at $410.1 million and $139.9 million, respectively. The liability component was measured using the nonconvertible debt interest rate. The carrying amount of the equity component representing the conversion option was determined by deducting the fair value of the liability component from the face value of the 2024 Convertible Notes as a whole. Since the Company must still settle these 2024 Convertible Notes at face value at or prior to maturity, this liability component will be accreted up to its face value resulting in additional non-cash interest expense being recognized within the Company’s condensed consolidated statements of income while the 2024 Convertible Notes remain outstanding. The effective-interest rate on the 2024 Convertible Notes is approximately 8.4% per annum. The equity component is not remeasured as long as it continues to meet the conditions for equity classification.

As of September 30, 2021, the outstanding principal on the 2024 Convertible Notes was $550.0 million, the unamortized debt discount and debt issuance costs were $70.6 million, and the carrying amount of the liability component was $479.4 million, which was recorded to long-term debt within the Company’s condensed consolidated balance sheet. As of December 31, 2020, the outstanding principal on the 2024 Convertible Notes was $550.0 million, the unamortized debt discount and debt issuance costs were $89.4 million, and the carrying amount of the liability component was $460.6 million, which was recorded to long-term debt within the Company’s condensed consolidated balance sheet. The fair value of the liability component relating to the 2024 Convertible Notes was approximately $548.6 million and $541.8 million as of September 30, 2021 and December 31, 2020, respectively.

During the three months ended September 30, 2021 and 2020, the Company recognized $10.0 million and $9.5 million, respectively, of interest expense relating to the 2024 Convertible Notes, which included $6.0 million and $5.5 million, respectively, relating to non-cash interest expense relating to the debt discount and $0.4 million and $0.4 million, respectively, relating to amortization of debt issuance costs. During the nine months ended September 30, 2021 and 2020, the Company recognized $29.6 million and $28.1 million, respectively, of interest expense relating to the 2024 Convertible Notes, which included $17.6 million and $16.2 million, respectively, relating to non-cash interest expense relating to the debt discount and $1.2 million and $1.1 million, respectively, relating to amortization of debt issuance costs.

Senior Notes due 2025

In May 2020, the Company issued $600.0 million aggregate principal amount of senior notes, or the 2025 Notes, in a private offering in the United States to qualified institutional buyers, pursuant to Rule 144A under the Securities Act of 1933, as amended, and outside the United States pursuant to Regulation S under the Securities Act of 1933, as amended. The 2025 Notes are senior unsecured obligations which rank effectively subordinate to any of the Company’s existing and future secured indebtedness, including amounts outstanding under the 2018 Credit Facility, to the extent of the value of the assets securing such indebtedness. The 2025 Notes pay interest at a rate of 7.875% per annum payable semiannually in arrears on March 1 and September 1 of each year, beginning on March 1, 2021. The 2025 Notes mature on September 1, 2025.

At any time prior to September 1, 2022, the Company may redeem all or part of the 2025 Notes at a redemption price equal to 100% of their principal amount, plus a “make whole” premium as of the redemption date, and accrued and unpaid interest to the redemption date. In addition, at any time prior to September 1, 2022, the Company may redeem up to 40% of the aggregate principal amount of the 2025 Notes with the proceeds of one or more equity offerings, at a redemption price equal to 107.875%, plus accrued and unpaid interest. Furthermore, at any time on or after September 1, 2022, the Company may redeem all or part of the 2025 Notes at the following redemption prices, expressed as percentages of principal amount, plus accrued and unpaid interest thereon to the redemption date, if redeemed during the twelve-month period beginning on September 1 of the years indicated below:

The 2025 Notes contain customary negative covenants, including, among other things, limitations or prohibitions on restricted payments, incurrence of additional indebtedness, liens, mergers, asset sales and transactions with affiliates. In addition, the 2025 Notes contain customary events of default.

The Company incurred approximately $7.9 million of issuance costs during the second quarter of 2020 relating to the issuance of the 2025 Notes. The $7.9 million of debt issuance costs, which was recorded as a debt discount on the Company’s condensed consolidated balance sheet, are being amortized over the contractual term of the 2025 Notes using the effective-interest method.

As of September 30, 2021, the outstanding principal on the 2025 Notes was $600.0 million, the unamortized debt issuance costs were $6.2 million, and the carrying amount was $593.8 million, which was recorded to long-term debt within the Company’s condensed consolidated balance sheet. As of December 31, 2020, the outstanding principal on the 2025 Notes was $600.0 million, the unamortized debt issuance costs were $7.1 million, and the carrying amount was $592.9 million, which was recorded to long-term debt within the Company’s condensed consolidated balance sheet. The fair value of the 2025 Notes was approximately $647.7 million and $656.3 million as of September 30, 2021 and December 31, 2020, respectively, and was determined by utilizing over-the-counter market quotes and yield curves, which are considered Level 2 inputs as defined in Note 12, Fair Value Measurements.

During the three months ended September 30, 2021 and 2020, the Company recognized $12.1 million and $12.1 million, respectively, of interest expense relating to the 2025 Notes, which included $0.4 million and $0.3 million, respectively, relating to amortization of debt issuance costs. During the nine months ended September 30, 2021 and 2020, the Company recognized $36.4 million and $16.4 million, respectively, of interest expense relating to the 2025 Notes, which included $1.0 million and $0.4 million, respectively, relating to amortization of debt issuance costs.

Senior Notes due 2026

In August 2018, the Company issued $400.0 million aggregate principal amount of senior notes, or the 2026 Notes, in a private offering in the United States to qualified institutional buyers, pursuant to Rule 144A under the Securities Act of 1933, as amended, and outside the United States pursuant to Regulation S under the Securities Act of 1933, as amended. The 2026 Notes were senior unsecured obligations which ranked effectively subordinate to any of the Company’s existing and future secured indebtedness, including amounts outstanding under the 2018 Credit Facility, to the extent of the value of the assets securing such indebtedness. The 2026 Notes paid interest at a rate of 7.250% per annum payable semiannually in arrears on February 15 and August 15 of each year, beginning on February 15, 2019. The 2026 Notes were to mature on August 15, 2026.

The Company incurred approximately $5.4 million of issuance costs during the third quarter of 2018 relating to the issuance of the 2026 Notes. The $5.4 million of debt issuance costs, which was recorded as a debt discount on the Company’s condensed consolidated balance sheet, were being amortized over the contractual term of the 2026 Notes using the effective-interest method.

In May 2021, the Company issued $600.0 million aggregate principal of new senior notes due 2029, or the 2029 Notes as described below, and subsequently used a portion of the proceeds to redeem all $400.0 million of its existing 2026 Notes for an aggregate purchase price of $428.5 million, which included $7.7 million of accrued interest. For accounting purposes, pursuant to ASC 470, these transactions were accounted for as an extinguishment of the 2026 Notes. The Company recognized a loss on extinguishment of $24.6 million as a result, which was recorded in other expense, net within the Company’s condensed consolidated statement of income for the three months ended June 30, 2021.

As of December 31, 2020, the outstanding principal on the 2026 Notes was $400.0 million, the unamortized debt issuance costs were $4.1 million, and the carrying amount was $395.9 million, which was recorded to long-term debt within the Company’s condensed consolidated balance sheet. The fair value of the 2026 Notes was approximately $425.0 million as of December 31, 2020 and was determined by utilizing over-the-counter market quotes and yield curves, which are considered Level 2 inputs as defined in Note 12, Fair Value Measurements.

During the three months ended September 30, 2020, the Company recognized $7.4 million of interest expense relating to the 2026 Notes, which included $0.1 million relating to amortization of debt issuance costs. During the nine months ended September 30, 2021 and 2020, the Company recognized $11.5 million and $22.2 million, respectively, of interest expense relating to the 2026 Notes, which included $0.2 million and $0.4 million, respectively, relating to amortization of debt issuance costs.

Senior Notes due 2029

In May 2021, the Company issued $600.0 million aggregate principal amount of senior notes, or the 2029 Notes, in a private offering in the United States to qualified institutional buyers, pursuant to Rule 144A under the Securities Act of 1933, as amended, and outside the United States pursuant to Regulation S under the Securities Act of 1933, as amended. The 2029 Notes are senior unsecured obligations which rank effectively subordinate to any of the Company’s existing and future secured indebtedness, including amounts outstanding under the 2018 Credit Facility, to the extent of the value of the assets securing such indebtedness. The 2029 Notes pay interest at a rate of 4.875% per annum payable semiannually in arrears on June 1 and December 1 of each year, beginning on December 1, 2021. The 2029 Notes mature on June 1, 2029.

At any time prior to June 1, 2024, the Company may redeem all or part of the 2029 Notes at a redemption price equal to 100% of their principal amount, plus a “make whole” premium as of the redemption date, and accrued and unpaid interest to the redemption date. In addition, at any time prior to June 1, 2024, the Company may redeem up to 40% of the aggregate principal amount of the 2029 Notes with the proceeds of one or more equity offerings, at a redemption price equal to 104.875%, plus accrued and unpaid interest. Furthermore, at any time on or after June 1, 2024, the Company may redeem all or part of the 2029 Notes at the following redemption prices, expressed as percentages of principal amount, plus accrued and unpaid interest thereon to the redemption date, if redeemed during the twelve-month period beginning on June 1 of the years indicated below:

The 2029 Notes contain customary negative covenants, including, among other things, limitations or prohibitions on restricted payments, incurrence of additional indebtedness, liens, mergers, asset sales and transactions with affiliates. In addition, the 2029 Notes contain customary events of default.

The Company incurred approximately $7.7 million of issuance costs during the second quarter of 2021 relating to the issuance of the 2029 Notes. The $7.7 million of debt issuance costs, which was recorded as a debt discount on the Company’s condensed consolidated balance sheet, are being amortized over the contractual term of the 2029 Notes using the effective-interest method.

As of September 30, 2021, the outstanding principal on the 2029 Notes was $600.0 million, the unamortized debt issuance costs were $7.4 million, and the carrying amount was $592.6 million, which was recorded to long-term debt within the Company’s condensed consolidated balance sheet. The fair value of the 2029 Notes was approximately $600.1 million as of September 30, 2021 and was determined by utilizing over-the-counter market quotes and yield curves, which are considered Level 2 inputs as defined in Note 12, Fair Value Measurements.

During the three months ended September 30, 2021, the Company recognized $7.5 million of interest expense relating to the 2029 Notes, which included $0.2 million relating to amortization of debt issuance costs. During the nine months ended September 30, 2021, the Company recognized $10.9 million of interest expense relating to the 2029 Notes, which included $0.3 million relating to amortization of debt issuance costs.

Valuation of 2024 Convertible Notes – Level 2 and Level 3 Inputs

In order to determine the initial value of the 2024 Convertible Notes, the Company determined the fair value of the liability component of the 2024 Convertible Notes using two valuation methods. The Company reviewed market data that was available for publicly traded, senior, unsecured nonconvertible corporate bonds issued by companies with similar credit ratings. Assumptions used in the estimate represent what market participants would use in pricing the liability component, including market yields and credit standing to develop the straight debt yield estimate. The Company also used a lattice model, which included inputs such as stock price, the Convertible Note trading price, volatility and dividend yield to estimate the straight debt yield. The Company combined the results of the two valuation methods to determine the fair value of the liability component of the 2024 Convertible Notes. Most of these inputs are primarily considered Level 2 and Level 3 inputs. The Company used similar valuation approaches to determine the subsequent fair value of the liability component only for disclosure purposes, which includes using a lattice model and (1) reviewing market data relating to its 2025 Notes and 2029 Notes and comparable yield curves to determine its straight debt yield estimate, or (2) reviewing market data relating to publicly traded, senior, unsecured nonconvertible corporate bonds issued by companies with similar credit ratings in order to determine its straight debt yield estimate.

Total Debt

The Company’s total interest expense was $38.8 million and $37.0 million for the three months ended September 30, 2021 and 2020, respectively, and $115.5 million and $96.4 million for the nine months ended September 30, 2021 and 2020, respectively, which was recognized within its condensed consolidated statements of income.