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Amarin (NASDAQ: AMRN) director reports RSU vesting and ADS tax withholding

Filing Impact
(Neutral)
Filing Sentiment
(Neutral)
Form Type
4

Rhea-AI Filing Summary

Amarin Corporation director Keith Horn reported routine equity compensation activity involving American Depositary Shares (ADSs). On April 18, 2026, 838 ADSs were issued upon the exercise of 838 Restricted Stock Units (RSUs), reflecting an earlier grant under Amarin’s 2020 Stock Incentive Plan. On the same date, 403 ADSs were withheld by Amarin to cover tax liabilities tied to this vesting, at an indicated value of $14.98 per ADS, which the company clarifies is not a market sale under Rule 16b-3. After these transactions, Horn directly owned 1,239 ADSs. Footnotes note that one ADS currently represents twenty ordinary shares following a prior ADS ratio change and that the original RSU grant totaled 2,514 units vesting in three equal annual installments.

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Insider Horn Keith
Role null
Type Security Shares Price Value
Exercise Restricted Stock Unit 838 $0.00 --
Exercise American Depositary Shares 838 $0.00 --
Tax Withholding American Depositary Shares 403 $14.98 $6K
Holdings After Transaction: Restricted Stock Unit — 838 shares (Direct, null); American Depositary Shares — 1,239 shares (Direct, null)
Footnotes (1)
  1. Effective April 11, 2025, the Issuer implemented a ratio change that one (1) American Depositary Share ("ADS") currently represents twenty (20) Ordinary Shares ("ADS Ratio Change"). Proportionate adjustments were made to the Issuer's outstanding equity awards. The amount of securities reported on this Form 4 reflect the ADS Ratio Change. On April 18, 2024, following the conclusion of the Issuer's annual general meeting of shareholders for 2024, the Reporting Person was granted 2,514 RSUs under the Amarin Corporation plc 2020 Stock Incentive Plan (the "Plan"). These RSUs vest in three equal installments on each of April 18, 2025, April 18, 2026 and April 18, 2027. Not applicable. Represents withholding by the Issuer of shares in respect of tax liability incident to the vesting of a security issued in accordance with Rule 16b-3, and not a market sale of securities. Each RSU represents a contingent right to receive twenty Ordinary Shares or cash in lieu thereof at the Issuer's discretion.
ADSs from RSU conversion 838 ADSs Non-derivative acquisition on April 18, 2026 from RSU exercise
ADSs withheld for taxes 403 ADSs Tax-withholding disposition at $14.98 per ADS on April 18, 2026
ADS holdings after transactions 1,239 ADSs Direct ownership following April 18, 2026 Form 4 transactions
RSU grant size 2,514 RSUs Granted April 18, 2024 under 2020 Stock Incentive Plan
ADS ratio 1 ADS = 20 ordinary shares Effective April 11, 2025 after ADS Ratio Change
Tax withholding reference price $14.98 per ADS Used for 403 ADSs withheld for tax liability
American Depositary Shares financial
"The security title for the reported transactions is American Depositary Shares."
American depositary shares (ADSs) are a way for investors in the United States to buy shares of foreign companies without dealing with international markets directly. They represent ownership in a foreign company's stock and are traded on U.S. stock exchanges, making it easier for American investors to buy, sell, and own parts of companies from around the world.
Restricted Stock Unit financial
"One transaction involves a derivative security titled Restricted Stock Unit."
A restricted stock unit is a promise from a company to give an employee shares of stock after certain conditions are met, like staying with the company for a set amount of time. It’s like earning a bonus that turns into company stock once you’ve proven your commitment, making it a way to motivate and reward employees.
Rule 16b-3 regulatory
"Tax withholding is described as incident to vesting of a security issued in accordance with Rule 16b-3."
Rule 16b-3 is a Securities and Exchange Commission regulation that exempts certain routine, pre-approved transactions by company insiders from automatic liability for short-term trading profits. It acts like a safe harbor: if an insider follows a formal plan or the board approves specific transactions in advance, profits from buying and selling company stock within six months are not automatically reclaimed. Investors care because the rule clarifies when insider trades are permissible and reduces uncertainty about potential clawbacks.
ADS Ratio Change financial
"The issuer implemented an ADS Ratio Change so one ADS represents twenty Ordinary Shares."
An ads ratio change is an adjustment to how many American Depositary Shares (ADS) represent one unit of a foreign company’s ordinary shares — like changing whether a cake is cut into 2 or 10 slices. Investors care because it alters the number of tradable ADS, the implied price per ADS and an investor’s ownership stake, which can affect liquidity, perceived value and comparisons of holdings across markets.
2020 Stock Incentive Plan financial
"RSUs were granted under the Amarin Corporation plc 2020 Stock Incentive Plan."
Form 4 Insider Transactions: What Each Field Means →
SEC Form 4
FORM 4UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number:3235-0287
Estimated average burden
hours per response:0.5
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
1. Name and Address of Reporting Person*
Horn Keith
(Last)(First)(Middle)
C/O AMARIN PHARMA, INC.
440 US HIGHWAY 22
(Street)
BRIDGEWATER NEW JERSEY 08807
(City)(State)(Zip)
UNITED STATES
(Country)		2. Issuer Name and Ticker or Trading Symbol
AMARIN CORP PLC\UK [ AMRN ] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
XDirector10% Owner
Officer (give title below)Other (specify below)
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
04/18/2026		6. Individual or Joint/Group Filing (Check Applicable Line)
XForm filed by One Reporting Person
Form filed by More than One Reporting Person
4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year)2A. Deemed Execution Date, if any (Month/Day/Year)3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeVAmount(A) or (D)Price
American Depositary Shares(1)04/18/2026M(2)838(1)A(3)1,239(1)D
American Depositary Shares(1)04/18/2026F(4)403(1)D$14.98836(1)D
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year)3A. Deemed Execution Date, if any (Month/Day/Year)4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year)7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Restricted Stock Unit(5)$004/18/2026M838(1) (2) (3)American Depositary Shares(1)838(1)$0838(1)D
Explanation of Responses:
1. Effective April 11, 2025, the Issuer implemented a ratio change that one (1) American Depositary Share ("ADS") currently represents twenty (20) Ordinary Shares ("ADS Ratio Change"). Proportionate adjustments were made to the Issuer's outstanding equity awards. The amount of securities reported on this Form 4 reflect the ADS Ratio Change.
2. On April 18, 2024, following the conclusion of the Issuer's annual general meeting of shareholders for 2024, the Reporting Person was granted 2,514 RSUs under the Amarin Corporation plc 2020 Stock Incentive Plan (the "Plan"). These RSUs vest in three equal installments on each of April 18, 2025, April 18, 2026 and April 18, 2027.
3. Not applicable.
4. Represents withholding by the Issuer of shares in respect of tax liability incident to the vesting of a security issued in accordance with Rule 16b-3, and not a market sale of securities.
5. Each RSU represents a contingent right to receive twenty Ordinary Shares or cash in lieu thereof at the Issuer's discretion.
/s/ Jonathan Provoost, by power of attorney04/21/2026
** Signature of Reporting PersonDate
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

Source: View Original Filing on SEC EDGAR

FAQ

What insider transactions did Amarin (AMRN) director Keith Horn report?

Keith Horn reported RSU vesting and related ADS movements. He acquired 838 American Depositary Shares from RSU conversion and had 403 ADSs withheld by Amarin for taxes, resulting in a net increase in direct holdings and 1,239 ADSs owned afterward.

Did Keith Horn actually sell Amarin (AMRN) shares in this Form 4 filing?

The filing shows no open-market sale of Amarin shares. Instead, 403 ADSs were withheld by Amarin to satisfy tax liability from RSU vesting, which the company states is a Rule 16b-3 tax-withholding transaction rather than a market sale of securities.

How many Amarin (AMRN) American Depositary Shares does Keith Horn own after these transactions?

After the reported transactions, Keith Horn directly owns 1,239 American Depositary Shares. This figure reflects the 838 ADSs received from RSU conversion on April 18, 2026, offset by 403 ADSs withheld by Amarin to cover associated tax obligations on the vesting.

What RSU grant underlies Keith Horn’s recent Amarin (AMRN) share activity?

The activity stems from a grant of 2,514 Restricted Stock Units awarded on April 18, 2024, under Amarin’s 2020 Stock Incentive Plan. These RSUs vest in three equal installments on April 18, 2025, April 18, 2026, and April 18, 2027, driving periodic ADS issuances.

What proportion of Keith Horn’s Amarin (AMRN) RSU grant vested in the latest transaction?

The filing shows 838 RSUs converting into ADSs on April 18, 2026. This matches one-third of the original 2,514-unit RSU grant, consistent with the stated vesting schedule of three equal annual installments in 2025, 2026, and 2027 under the stock incentive plan.