11.           Long-term debt

On June 14, 2013, the Company entered into a venture debt loan facility with Hercules Capital, Inc. (“Hercules”). The facility has been amended at various times, including on July 22, 2024 (the “2024 Amended Facility”) and most recently on September 22, 2025 (the “2025 Amended Facility”), upon which date the amendment closed (the “Amendment Closing Date”).

On the Amendment Closing Date, the Company drew down $50.0 million of the 2025 Amended Facility to repay the $50.0 million then outstanding under the 2024 Amended Facility. A facility charge of $0.2 million was incurred on the Amendment Closing Date. The 2024 Amended Facility was due on January 7, 2027 and bore interest at a rate equal to the greater of (i) 7.95% and (ii) 7.95% plus the prime rate less 3.25% per annum, reflecting a floating rate of 11.95% at the Amendment Closing Date.

Pursuant to the 2025 Amended Facility, additional term loans of $125.0 million were made available. The Company may draw down (i) an additional $100.0 million in two increments of at least $25.0 million, following the approval of a Biologics License Application (“BLA”) for AMT-130 prior to June 15, 2027, provided that confirmatory trials to the extent and in the manner required to support full approval (if applicable) remain ongoing or are being planned, and (ii) an additional $25.0 million in a single advance, subject to approval by Hercules. Advances under the 2025 Amended Facility bear interest at a rate equal to the greater of (i) 9.45% and (ii) the sum of the prime rate and 2.45%, reflecting a floating rate of 9.45% as per December 31, 2025.

The 2025 Amended Facility matures on October 1, 2030, upon which date the Company is required to repay the principal balance and any unpaid interest on advances received. The interest-only period of the 2025 Amended Facility is effective through October 1, 2028. The interest-only period will be extended to October 1, 2029 if the BLA for AMT-130 is approved prior to June 15, 2027. The 2025 Amended Facility will be interest-only if certain commercial milestones are met prior to December 31, 2028.

The Company may prepay all or part of the outstanding principal together with a prepayment charge of 1.50% if repayment occurs within the first 30 months following the Amendment Closing Date, and thereafter, with a prepayment charge of 0.75%. An end-of-term charge of 2.75% of the aggregate principal outstanding is due if repaid within 18 months of the Amendment Closing Date, otherwise 5.50% if repaid thereafter.

The total principal outstanding as of December 31, 2025 under the 2025 Amended Facility was $50.0 million. The amortized cost, including interest due presented as part of Accrued expenses and other current liabilities, was $50.1 million as of December 31, 2025, compared to $51.9 million as of December 31, 2024, and is recorded net of discount and debt issuance costs. The foreign currency gain on the loan facility for the year ended December 31, 2025 was $9.3 million, compared to a foreign currency loss of $4.1 million for the year ended December 31, 2024. The fair value of the loan approximates its carrying amount. Inputs to the fair value of the loan are considered Level 3 inputs.

Interest expense recorded during the years ended December 31 was as follows:

Years

  ​ ​ ​

Amount

(in millions)

2025

$

6.9

2024

 

12.9

2023

14.6

Under the 2025 Amended Facility, the Company must remain current in its periodic reporting requirements. Unless the Company maintains a minimum market capitalization threshold of at least $1,200.0 million, the Company, beginning January 1, 2027, is required at all times to keep a minimum cash balance deposited in bank accounts in the U.S. of at least the lesser of (i) 65% of the outstanding balance of aggregate principal due, provided that such percentage will be reduced to 50% upon the occurrence of the approval of a BLA for AMT-130 prior to June 15, 2027, and further reduced to 35% upon the occurrence of the contractually defined commercial milestones or (ii) 100% of worldwide cash and cash equivalents. The 2025 Amended Facility also provides for a certain performance covenant related to AMT-130 net product revenue which would apply nine months past a potential BLA approval of AMT-130, unless the Company maintains a minimum market capitalization threshold of at least $1,200.0 million. The 2025 Amended Facility restricts the Company’s ability, among other things, to incur future indebtedness and obtain additional debt financing, make investments in securities or in other companies, transfer assets, perform certain corporate changes, own or hold certain digital assets, make loans to employees, officers, and directors, and make dividend payments and other distributions to its shareholders. The 2025 Amended Facility is secured by a direct or indirect pledge of the Company’s total assets of $824.9 million, less $35.5 million of cash and cash equivalents and other current assets held by the Company, and $88.8 million of other current assets and investments held by uniQure France SAS as well as receivables sold to HemB SPV, L.P. as described in Note 12 “Royalty Financing Agreement”. In accordance with the 2025 Amended Facility, the Company was in compliance with all applicable covenants as of December 31, 2025.

The aggregate maturities of the loan, including $21.9 million of coupon interest payments and financing fees, for each of the 58 months after December 31, 2025, are as follows:

Years

  ​ ​ ​

Amount

(in thousands)

2026

$

4,791

2027

5,416

2028

10,243

2029

26,534

2030

24,938

Total

$

71,922

Historical Timeline

Fiscal YearFiled
2025Mar 2, 2026Showing above
2023Feb 28, 2024
2022Feb 27, 2023
2021Feb 25, 2022
2020Mar 1, 2021
2019Mar 2, 2020
2018Feb 28, 2019
2017Mar 14, 2018
2016Mar 15, 2017

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.