Form 4 Filing for Diane E. Sullivan

On April 18, 2026, Diane E. Sullivan, a director at AMARIN CORP PLC\UK, was granted 838 Restricted Stock Units (RSUs) with a transaction value of $0. This grant is part of the Amarin Corporation plc 2020 Stock Incentive Plan and vests in three equal installments on April 18, 2025, April 18, 2026, and April 18, 2027. The filing also reports the withholding of 403 shares by the issuer in respect of tax liability related to the vesting of a security, with a transaction value of $14.98 per share. These transactions are adjusted for the Issuer's ratio change implemented on April 11, 2025, where one ADS now represents twenty Ordinary Shares. Following these transactions, Sullivan holds 1239 shares directly and 836 shares directly.