ALNYLAM PHARMACEUTICALS, INC.ALNY
ALNYLAM PHARMACEUTICALS, INC. Debt Disclosure
8. CONVERTIBLE DEBT AND OTHER FINANCING
Convertible Senior Notes Due 2028
On September 8, 2025, we commenced a private offering of $575.0 million in aggregate principal amount of 0.00% convertible senior notes due 2028, or the Initial 2028 Notes. On September 10, 2025, the initial purchasers in such offering exercised their option to purchase an additional $86.3 million in aggregate principal amount of our 0.00% Convertible Senior Notes due 2028, or the Additional 2028 Notes, and together with the Initial 2028 Notes referred to as the 2028 Notes, bringing the total aggregate principal amount of the 2028 Notes issued and outstanding to $661.3 million. The 2028 Notes are our senior unsecured obligations. The 2028 Notes were issued pursuant to an indenture, dated September 12, 2025, or the 2025 Indenture, between us and The Bank of New York Mellon, as trustee. The 2025 Indenture includes customary covenants and sets forth certain events of default after which the 2028 Notes may be declared immediately due and payable and sets forth certain types of bankruptcy or insolvency events of default involving us after which the 2028 Notes become automatically due and payable. The 2028 Notes will mature on September 15, 2028, unless earlier converted, redeemed or repurchased. The 2028 Notes will not bear regular interest.
Before June 15, 2028, noteholders will have the right to convert their 2028 Notes in certain circumstances and during specified periods: (1) during any calendar quarter commencing after the calendar quarter ending on December 31, 2025 (and only during such calendar quarter), if the last reported sale price of our common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the five business day period after any ten consecutive trading day period in which the trading price per $1,000 principal amount of the 2028 Notes for each trading day of that ten consecutive trading day period was less than 98% of the product of the last reported sale price of our common stock and the conversion rate on such trading day; (3) if we call any or all of the 2028 Notes for redemption; or (4) upon the occurrence of specified corporate events. From and after June 15, 2028, the 2028 Notes will be convertible at the option of the noteholders at any time prior to the close of business on the second scheduled trading day immediately preceding the maturity date.
We will settle any conversions of the 2028 Notes by paying or delivering, as applicable, cash, shares of our common stock, or a combination of cash and shares of common stock, at our election. The conversion rate for the 2028 Notes will initially be 1.4923 shares of common stock per $1,000 principal amount of 2028 Notes, which is equivalent to an initial conversion price of approximately $670.11 per share of common stock. The initial conversion price represents a premium of approximately 40% above the U.S. composite volume weighted average price of our common stock from 12:30 p.m. through 4:00 p.m. Eastern Daylight Time on September 9, 2025, which was $478.63 per share. The conversion rate is subject to adjustment under certain circumstances in accordance with the terms of the 2025 Indenture.
We may not redeem the 2028 Notes prior to September 20, 2027. We may redeem for cash all or any portion of the 2028 Notes (subject to certain limitations), at our option, on or after September 20, 2027 and on or prior to the 21st scheduled trading day immediately preceding the maturity date, if the last reported sale price of our common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive), including the trading day immediately preceding the date on which we provide notice of redemption, during any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which we provide notice of redemption at a redemption price equal to 100% of the principal amount of the 2028 Notes to be redeemed, plus any accrued and unpaid special interest to, but excluding, the redemption date. No sinking fund is provided for the 2028 Notes, which means that we are not required to redeem or retire the 2028 Notes periodically.
If we undergo a fundamental change, which includes certain change of control events or a termination of trading of our common stock, then subject to certain conditions, holders may require us to repurchase for cash all or any portion of their notes at a fundamental change repurchase price equal to 100% of the principal amount of the 2028 Notes to be repurchased plus accrued and unpaid special interest. In addition, if specific corporate events occur prior to the maturity date or if we issue a notice of redemption, we will increase the conversion rate by pre-defined amounts for holders who elect to convert their notes in connection with such corporate event. The conditions allowing holders of the 2028 Notes to convert were not met as of December 31, 2025.
The 2028 Notes were issued at par. As of December 31, 2025, the 2028 Notes were classified as a long-term liability on the consolidated balance sheet and had a carrying value of $647.2 million, representing the outstanding principal amount, net of unamortized issuance costs of $14.0 million. The issuance costs are amortized to interest expense over the contractual term of the 2028 Notes. As of December 31, 2025, the estimated fair value of the 2028 Notes was approximately $637.0 million, which was determined based on the last actively traded price per $100 of the 2028 Notes (Level 2) on that day. As of December 31, 2025, the effective interest rate of the 2028 Notes is 1%.
We used the net proceeds from the issuance of the 2028 Notes to pay the cost of the 2025 Capped Call Transactions, and the remainder of the net proceeds, together with cash on hand, to repay $637.8 million aggregate principal amount of the 2027 Notes, as further discussed below.
2025 Capped Call Transactions
In September 2025, in connection with the pricing of the 2028 Notes, we entered into privately negotiated capped call transactions, or 2025 Capped Call Transactions. The 2025 Capped Call Transactions initially cover, subject to customary anti-dilution adjustments, the number of shares of common stock that underlie the 2028 Notes. The initial cap price of the 2025 Capped Call Transactions is $837.61 per share, and is subject to certain adjustments under the terms of the 2025 Capped Call Transactions.
The 2025 Capped Call Transactions are not part of the terms of the 2028 Notes and are accounted for as separate transactions. As these transactions are indexed to our own stock and are considered equity classified, they are recorded in stockholders’ equity and are not accounted for as derivatives. The cost incurred in connection with the 2025 Capped Call Transactions of $35.3 million was recorded as a reduction to additional paid-in capital on our consolidated balance sheet and the fair value of the capped call instrument is not remeasured each reporting period.
Convertible Senior Notes Due 2027
On September 12, 2022, we commenced a private offering of $900.0 million in aggregate principal amount of 1.00% Convertible Senior Notes due 2027, or the Initial 2027 Notes. On September 13, 2022, the initial purchasers in such offering exercised their option to purchase an additional $135.0 million in aggregate principal amount of our 1.00% Convertible Senior Notes due 2027, or the Additional 2027 Notes, and together with the Initial 2027 Notes collectively referred to as the 2027 Notes, bringing the total aggregate principal amount of the 2027 Notes issued and outstanding to $1.04 billion. The 2027 Notes were issued pursuant to an indenture, dated September 15, 2022, or the 2022 Indenture. The 2022 Indenture includes customary covenants and sets forth certain events of default after which the 2027 Notes may be declared immediately due and payable and sets forth certain types of bankruptcy or insolvency events of default involving us after which the 2027 Notes become automatically due and payable. The 2027 Notes were issued at par.
The 2027 Notes will mature on September 15, 2027, unless earlier converted, redeemed or repurchased. The 2027 Notes bear interest at a rate of 1.00% per year payable semiannually in arrears on March 15 and September 15 of each year, beginning on March 15, 2023. The 2027 Notes are convertible at the option of the noteholder on or after June 15, 2027. Prior to June 15, 2027, the 2027 Notes are convertible only under the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on December 31, 2022 (and only during such calendar quarter), if the last reported sale price of our common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the five business day period after any ten consecutive trading day period in which the trading price per $1,000 principal amount of the 2027 Notes for each trading day of that ten consecutive trading day period was less than 98% of the product of the last reported sale price of our common stock and the conversion rate of the 2027 Notes on such trading day; (3) if we call any or all of the 2027 Notes for redemption; or (4) upon the occurrence of specific corporate events as set forth in the 2022 Indenture governing the 2027 Notes.
We will settle any conversions of the 2027 Notes by paying or delivering, as applicable, cash, shares of our common stock, or a combination of cash and shares of common stock, at our election. The initial conversion rate for the 2027 Notes is 3.4941 shares of common stock per $1,000 principal amount, which is equivalent to an initial conversion price of approximately $286.20 per share of common stock, which represents a premium of approximately 35% over the last reported sale price of common stock of $212.00 per share on September 12, 2022. The conversion rate is subject to adjustment under certain circumstances in accordance with the terms of the 2022 Indenture. The condition allowing holders of the 2027 Notes to convert was met in the fourth quarter of 2025 due to our common stock trading for at least 20 days during a period of 30 consecutive trading days ending on, and including, the last trading day of the quarter above 130% of the conversion price, and the 2027 Notes are convertible at the option of the holders in the first quarter of 2026.
We are able to redeem the 2027 Notes after September 20, 2025. We may redeem for cash equal to 100% of the principal amount of the 2027 Notes being redeemed plus accrued and unpaid interest of all or any portion of the 2027 Notes, at our option, on or after September 20, 2025, if the last reported sales price of our common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period. As of December 31, 2025, we have not redeemed any of the 2027 Notes under this option.
No sinking fund is provided for the 2027 Notes and therefore we are not required to redeem or retire the 2027 Notes periodically. If we undergo a fundamental change, which includes certain change of control events or a termination of trading of our common stock, then subject to certain conditions, holders may require us to repurchase for cash all or any portion of their 2027 Notes at a fundamental change repurchase price equal to 100% of the principal amount of the 2027 Notes to be repurchased plus accrued and unpaid interest. In addition, if specific corporate events occur prior to the maturity date or if we issue a notice of redemption, we will increase the conversion rate by pre-defined amounts for holders who elect to convert their notes in connection with such corporate event.
In September 2025, concurrently with the pricing of the 2028 Notes, we entered into privately negotiated transactions with certain holders of the 2027 Notes to repurchase for cash $637.8 million aggregate principal amount of the outstanding 2027 Notes for a total repurchase cost (including accrued and unpaid interest of $3.1 million) of approximately $1.11 billion. The repurchase was accounted for as an induced conversion in accordance with ASU 2024-04. We recorded an inducement expense of $39.1 million within loss related to convertible debt in the consolidated statements of operations and comprehensive income (loss) for the year ended December 31, 2025 and a charge to additional paid-in capital of $430.4 million within stockholders’ equity.
In December 2025, we entered into privately negotiated transactions with certain holders of the 2027 Notes to repurchase for cash $34.4 million aggregate principal amount of the outstanding 2027 Notes for a total repurchase cost (including accrued and unpaid interest of $0.1 million) of approximately $52.3 million. The repurchase was accounted for as an induced conversion in accordance with ASU 2024-04. We recorded an inducement expense of $3.3 million within loss related to convertible debt in the consolidated statements of operations and comprehensive income (loss) for the year ended December 31, 2025 and a charge to additional paid-in capital of $14.8 million within stockholders’ equity.
As of December 31, 2025, we had $362.8 million aggregate principal amount of the 2027 Notes outstanding. As of December 31, 2025 and 2024, the 2027 Notes were classified as a long-term liability on the consolidated balance sheets and had a carrying value of $360.5 million and $1.02 billion, respectively, representing outstanding principal amount net of unamortized issuance costs of $2.3 million and $10.4 million, respectively. The issuance costs are amortized to interest expense over the contractual term of the 2027 Notes. As of December 31, 2025 and 2024, the estimated fair value of the 2027 Notes was approximately $534.1 million and $1.11 billion, respectively, which was determined based on the last actively traded price per $100 of the 2027 Notes (Level 2) on the respective dates. As of December 31, 2025 and 2024, the effective interest rate of the 2027 Notes is 1%.
2022 Capped Call Transactions
In 2022, in connection with the pricing of the 2027 Notes, we entered into privately negotiated capped call transactions, or 2022 Capped Call Transactions. The 2022 Capped Call Transactions initially cover, subject to customary anti-dilution adjustments, the number of shares of common stock that underlie the 2027 Notes. The cap price of the 2022 Capped Call Transactions is initially $424.00 per share, which represents a premium of 100% over the last reported sale price of common stock of $212.00 per share on September 12, 2022, and is subject to certain adjustments under the terms of the 2022 Capped Call Transactions. As of December 31, 2025, the 2022 Capped Call Transactions remained outstanding. Because these transactions are indexed to our own stock and are considered equity classified, they were recorded in stockholders’ equity and are not accounted for as derivatives. The cost incurred to purchase the 2022 Capped Calls was recorded as a reduction to additional paid-in capital on our consolidated balance sheets and the fair value of the capped call instrument is not remeasured each reporting period.
Revolving Credit Agreement
On September 30, 2025, we entered into the Revolving Credit Agreement, which provides for a $500.0 million revolving line of credit, including a $150.0 million sublimit for issuance of letters of credit. The Revolving Credit Agreement matures in September 2030, subject to earlier springing maturity under certain circumstances.
Borrowings, if any, will bear interest, at our option, at a base rate plus an applicable margin ranging from 0.50% to 1.50% based upon the total leverage ratio or a term Secured Overnight Financing Rate (or an alternative currency term rate) plus an applicable margin ranging from 1.50% to 2.50% based upon the total leverage ratio. We are required to pay, on a quarterly basis, a commitment fee ranging between 0.20% to 0.35% (depending on our total leverage ratio) of unused available commitments under the Revolving Credit Agreement. We are also obligated to pay the administrative agent fees customary for revolving credit facilities of this size and type.
The Revolving Credit Agreement contains customary affirmative and negative covenants and conditions to borrowing, as well as customary events of default. In addition, the Revolving Credit Agreement contains financial covenants that require us to maintain a total leverage ratio less than or equal to 3.75:1.00 and an interest coverage ratio greater than or equal to 3.00:1.00, each tested at the end of each fiscal quarter. As of December 31, 2025, we were in compliance with the financial covenants.
As of December 31, 2025, we had no borrowings and $17.5 million of letters of credit outstanding under the Revolving Credit Agreement.
Historical Timeline
| Fiscal Year | Filed | |
|---|---|---|
| 2025 | Feb 12, 2026 | Showing above |
| 2024 | Feb 13, 2025 | |
| 2023 | Feb 15, 2024 | |
| 2022 | Feb 23, 2023 | |
| 2021 | Feb 10, 2022 | |
| 2020 | Feb 11, 2021 | |
| 2019 | Feb 13, 2020 | |
| 2018 | Feb 14, 2019 | |
About Debt Disclosures
Debt disclosures detail a company's borrowing structure — the types of instruments, interest rates, maturity schedule, and covenant restrictions that define its financial obligations and flexibility. This section is essential for assessing refinancing risk, interest rate exposure, and the margin of safety against financial distress.
Key signals: the maturity schedule reveals concentration risk — large maturities within 1-2 years during tight credit markets can force dilutive refinancing or asset sales. Compare the fair value of debt against carrying amount to gauge whether the market views the company's credit risk differently than the balance sheet suggests. Watch covenant compliance disclosures for tightening cushions, especially leverage and interest coverage ratios. Variable-rate debt exposure quantifies sensitivity to interest rate changes. Secured versus unsecured mix affects recovery rates and future borrowing capacity. Compare net debt-to-EBITDA against industry peers and covenant limits to assess financial health.