Amarin director’s RSUs vest with tax withholding

Amarin Corporation director Oliver O’Connor reported routine equity compensation activity involving American Depositary Shares (ADSs).

Rhea-AI Filing Summary

Amarin Corporation director Oliver O’Connor reported routine equity compensation activity involving American Depositary Shares (ADSs). On April 18, he acquired 838 ADSs through the vesting and conversion of Restricted Stock Units, while 438 ADSs were withheld by the company to cover tax obligations.

After these transactions, he directly held 801 ADSs. A prior grant on April 18, 2024 covered 2,514 RSUs vesting in three equal installments on April 18, 2025, 2026 and 2027. Each RSU represents a contingent right to receive one ADS, and each ADS currently represents twenty ordinary shares after an ADS ratio change.

Insider Trade Summary

838 shares exercised/converted

Exercise 3 txns

Insider O'Connor Oliver

Role Director

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Unit	838	$0.00	$0.00
Exercise	American Depositary Shares	838	$0.00	$0.00
Exercise Price or Tax Liability	American Depositary Shares	438	$14.98	$7K

Holdings After Transaction: Restricted Stock Unit — 838 contracts (Direct); American Depositary Shares — 801 shares (Direct)

Footnotes (5)

1. F1. 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. F2. 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. F3. Not applicable.
4. F4. 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. F5. Each RSU represents a contingent right to receive twenty Ordinary Shares or cash in lieu thereof at the Issuer's discretion.

Key Figures

ADS acquired from RSU vesting: 838 ADSs ADS withheld for taxes: 438 ADSs ADS held after transactions: 1,239 ADSs +4 more

7 metrics

ADS acquired from RSU vesting 838 ADSs Non-derivative acquisition on April 18, 2026

ADS withheld for taxes 438 ADSs Tax-withholding disposition on April 18, 2026

ADS held after transactions 1,239 ADSs Direct holdings following April 18, 2026 activity

Original RSU grant 2,514 RSUs Granted April 18, 2024 under 2020 Stock Incentive Plan

RSU vesting installments 838 RSUs each Vest on April 18, 2025, 2026 and 2027

ADS to ordinary share ratio 1 ADS : 20 ordinary shares ADS Ratio Change effective April 11, 2025

Tax withholding price reference $14.98 per ADS Price used for 438 ADS tax withholding

Key Terms

American Depositary Shares, Restricted Stock Unit, Rule 16b-3, ADS Ratio Change, +1 more

5 terms

American Depositary Shares financial

"The Issuer implemented a ratio change that one American Depositary Share currently represents twenty Ordinary 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

"On April 18, 2024, the Reporting Person was granted 2,514 RSUs under the Amarin Corporation plc 2020 Stock Incentive Plan."

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

"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."

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 a ratio change that one ADS currently represents twenty Ordinary Shares (ADS Ratio Change)."

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.

Stock Incentive Plan financial

"The Reporting Person was granted 2,514 RSUs under the Amarin Corporation plc 2020 Stock Incentive Plan."

A stock incentive plan is a company program that gives employees or directors pieces of ownership or the right to buy shares over time, similar to receiving a bonus paid in company stock instead of cash. Investors pay attention because these plans align staff incentives with long‑term company performance but can also dilute existing shareholders and affect reported profits when grants are expensed, so they influence both ownership percentages and financial results.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transactions did Amarin (AMRN) director Oliver O’Connor report?

He reported RSU vesting into 838 American Depositary Shares and withholding of 438 ADSs for taxes. These were compensation-related entries, not open-market trades, reflecting equity awards previously granted under Amarin’s 2020 Stock Incentive Plan.

Did Amarin (AMRN) director Oliver O’Connor sell shares in the open market?

No, the filing states 438 ADSs were withheld by Amarin to satisfy tax liabilities from RSU vesting. Footnotes clarify this withholding was made under Rule 16b-3 and is not considered a market sale of securities.

How many Amarin (AMRN) ADSs does Oliver O’Connor hold after these transactions?

Following the April 18 transactions, O’Connor directly holds 1,239 American Depositary Shares. This total reflects both the 838 ADSs received from RSU vesting and the 438 ADSs withheld to cover taxes, as disclosed in the Form 4 data.

What RSU grant underpins Oliver O’Connor’s recent Amarin (AMRN) filings?

The activity relates to a 2,514 RSU grant 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, subject to the plan’s terms.

How does the ADS ratio change affect Amarin (AMRN) director equity awards?

Effective April 11, 2025, one ADS represents twenty ordinary shares. Footnotes state Amarin made proportionate adjustments to outstanding equity awards, and the amounts reported in this Form 4 already reflect the updated ADS ratio for these securities.

What does each Amarin (AMRN) RSU represent for Oliver O’Connor?

Each RSU represents a contingent right to receive one American Depositary Share, which equals twenty ordinary shares. Amarin may instead deliver cash in lieu of shares at its discretion, as described in the filing’s RSU footnote language.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 04/21/2026 - 05:00 PM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED 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^*

O'Connor Oliver

(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)

X	Director		10% 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)

X	Form 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)
			Code	V	Amount	(A) or (D)	Price
American Depositary Shares(1)	04/18/2026		M(2)		838(1)	A	(3)	1,239(1)	D
American Depositary Shares(1)	04/18/2026		F(4)		438(1)	D	$14.98	801(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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Unit(5)	$0	04/18/2026		M		838(1)		(2)	(3)	American Depositary Shares(1)	838(1)	$0	838(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 attorney	04/21/2026
	** Signature of Reporting Person	Date
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.
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* Form 4: SEC 1474 (03-26)