License Agreement with Amoytop

In May 2026, the Company and Xiamen Amoytop Biotech Co., Ltd (Amoytop) entered into a License Agreement (the Amoytop License Agreement) to develop and commercialize pevifoscorvir sodium in Greater China for chronic HBV infection. Along with a $25.0 million, net of tax, upfront payment, Aligos is entitled to up to $420 million in clinical, regulatory, and sales milestones with tiered, high single-digit royalties. These potential payments consist of (i) development milestones and (ii) sales-based milestones. Under the terms of the agreement, the Company received an upfront payment of $25.0 million, net of tax, in July 2026.

The Company determined that the Amoytop License agreement falls within the scope of ASC 606. The agreement did not fall under the ASC 808 guidance due to Amoytop and the Company not being joint active participants, and both parties not having significant risks and rewards. Management of the Company determined that the provision of the license along with initial transfer of know-how were not distinct within the context of the contract and therefore represent a single performance obligation and the related upfront payment is recognized at a point in time. In addition, variable consideration (e.g., milestone payments and royalties) was

evaluated based on the Company’s analysis that the probability of achieving any of the milestone payments is remote, and therefore determined to be constrained and excluded from the transaction price.

During the three and six months ended June 30, 2026, the Company recognized $27.8 million in revenue from license agreements related to the upfront payment with a corresponding amount in accounts receivable. In addition, an amount of $2.8 million of withholding taxes was recognized as income tax expense with a corresponding liability. During the three and six months ended June 30, 2025, there was no revenue from licensing agreements recognized.

Research Collaboration Agreement with Amoytop

In May 2023, the Company and Amoytop entered into a Research Collaboration and Development Agreement (the Amoytop Collaboration Agreement) with a focus on nucleic acid technology for HBV treatment, with the Company granting to Amoytop an exclusive, time-limited option to enter into an exclusive, territory-limited license to develop and commercialize such compounds. Under the terms of the agreement, the Company received an upfront payment of $7.0 million, less withholding taxes of $1.1 million from Amoytop. With respect to the agreement, the Company is eligible for up to $109.0 million in development and commercialization milestones as well as tiered royalties on net sales. These potential payments consist of (i) potential development milestones (such as for the commencement of a Good Laboratory Practice toxicology study for a collaboration compound, approval of IND by regulatory authority, initiation of Phase 2 and 3 clinical trials, and regulatory approval of a licensed product), and (ii) sales-based milestones.

In May 2024, the Company and Amoytop entered into an extension to the Amoytop Collaboration Agreement, covering work performed through January 2025. Under the terms of the agreement, the Company received an upfront payment of $1.5 million, which was recognized as revenue from contracts with customers from the second quarter of 2024 through the first quarter of 2025.

In May 2025, the Company and Amoytop entered into an additional extension to the Amoytop Collaboration Agreement, covering work performed through approximately November 2025. Under the terms of the agreement, the Company received an upfront payment of $1.0 million, which was recognized as revenue from contracts with customers from the second quarter of 2025 through the fourth quarter of 2025.

In September 2025, Amoytop exercised its option to obtain an exclusive, territory-limited license to one compound developed under the Amoytop Collaboration Agreement, with the right to choose an alternative compound among three identified candidates following the completion of certain IND-enabling studies. IND-enabling studies began on its chosen compound in January 2026, which earned the Company a milestone payment of $3.0 million which was recognized as revenue from contracts with customers. In July 2026, Amoytop received IND approval in China on its chosen compound, which earned the Company a milestone payment of $3.0 million.

The Company determined that the Amoytop Collaboration Agreement falls within the scope of ASC 606. The agreement did not fall under the ASC 808 guidance due to Amoytop and the Company not being joint active participants, and both parties not having significant risks and rewards. Management of the Company determined that there were three performance obligations for the agreement given the deliverables are distinct. The Company evaluated the standalone selling price for each obligation based on available data for similar arrangements. The Company evaluated the performance obligations and determined the provision of R&D services for the collaboration compound performance obligation will be satisfied over time, the research license including data and know-how has been satisfied, and the provision of materials will be satisfied upon delivery. Given the nature of the arrangement, the Company believes that the satisfaction of its performance obligations is best measured by the progress of its efforts as it relates to the performance of the R&D services. As such, the Company has used an input method based on costs incurred to recognize revenue associated with the upfront payments, and the Company recognizes revenue over time based on the costs incurred. The effect of any updates to the estimated overall costs are recorded as a change in estimate. In addition, variable consideration (e.g., milestone payments) were evaluated based on the Company’s analysis that the probability of achieving any of the milestone payments is remote, and therefore determined to be constrained and excluded from the transaction price.

During the three months ended June 30, 2026, the Company recognized no revenue from customers related to upfront or milestone payments. During the six months ended June 30, 2026, the Company recognized $2.8 million in revenue from customers related to a milestone payment of $3.0 million less withholding taxes.

During the three and six months ended June 30, 2025, the Company recognized no revenue from customers related to milestone payments. During the three and six months ended June 30, 2025, the Company recognized $1.0 million and $1.3 million, respectively, in revenue from customers related to upfront payments.