[Form 4] Mereo BioPharma Group plc Insider Trading Activity

Rhea-AI Filing Summary

Mereo BioPharma Group plc director Marc J. Yoskowitz reported equity compensation awards. He received share options covering 66,000 shares at an exercise price of $0.0000 per share, classified as a grant or award acquisition.

He was also granted 96,163 deferred restricted stock units, which are provided in the form of American Depositary Shares instead of annual cash compensation. The options vest in substantially equal monthly installments over one year from the February 26, 2026 grant date, while the deferred restricted stock units vest in substantially equal monthly installments over the plan year and are generally settled in ADSs 180 days after separation of service.

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

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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^*

Yoskowitz Marc J

(Last) (First) (Middle)

C/O MEREO BIOPHARMA GROUP PLC

4TH FLOOR, ONE CAVENDISH PLACE

(Street)

LONDON X0 W1G 0QF

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Mereo BioPharma Group plc [ MREO ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
02/26/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

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

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
Share Options (Right to buy)	$0.39	02/26/2026		A		66,000		(1)	02/26/2036	American Depositary Shares(2)	66,000	$0	66,000	D
Deferred Restricted Stock Units	(3)	02/26/2026		A		96,163		(3)	(3)	American Depository Shares(2)	96,163	(3)	96,163	D

Explanation of Responses:

1. Vests in substantially equal monthly installments over a one year period from the February 26, 2026 grant date.

2. Each American Depositary Share ("ADS") represents five ordinary shares, nominal value GBP 0.003 per ordinary share, of the Issuer.

3. Deferred restricted stock units ("DRSU") are granted to non-executive directors who elected to receive DRSUs in the form of ADSs in lieu of annual cash compensation. DRSUs vest in substantially equal monthly installments over the plan year following the grant date. Payment of DRSUs in ADSs will generally be made 180 days following separation of service.

	/s/ Christine Fox, by power of attorney	02/27/2026
	** 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.
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.

FAQ

What insider transactions did Mereo BioPharma (MREO) report for Marc J. Yoskowitz?

Marc J. Yoskowitz reported grants of equity awards, not open-market trades. He received options on 66,000 shares and 96,163 deferred restricted stock units, both classified as grant or award acquisitions on February 26, 2026.

Were the Mereo BioPharma (MREO) insider awards to Marc J. Yoskowitz purchases or sales?

The awards were grants, not purchases or sales. The Form 4 classifies both the share options and deferred restricted stock units as grant or award acquisitions, with no cash price per share reported for these derivative securities.

What are the key terms of Marc J. Yoskowitz’s option grant at Mereo BioPharma (MREO)?

He received share options on 66,000 shares at an exercise price of $0.0000 per share. These options vest in substantially equal monthly installments over a one-year period starting from the February 26, 2026 grant date.

How do the deferred restricted stock units for Mereo BioPharma (MREO) vest and pay out?

Marc J. Yoskowitz received 96,163 deferred restricted stock units granted in the form of ADSs. They vest in substantially equal monthly installments over the plan year, and payment in ADSs generally occurs 180 days after separation of service.

Why did Marc J. Yoskowitz receive deferred restricted stock units at Mereo BioPharma (MREO)?

The filing states that deferred restricted stock units are granted to non-executive directors who elect to receive these units in the form of American Depositary Shares instead of their annual cash compensation for board service.

What is the relationship between Mereo BioPharma (MREO) ADSs and ordinary shares in this Form 4?

The footnotes explain that each American Depositary Share represents five ordinary shares of Mereo BioPharma Group plc, each ordinary share having a nominal value of GBP 0.003 according to the disclosure.