Insider filing report for Changes in Beneficial Ownership
- Schedule 13G & 13D forms are used to report a party's ownership of stock which exceeds 5% of a company's total stock issue.
- Schedule 13G is a shorter version of Schedule 13D with fewer reporting requirements.
"Insiders might sell their shares for any number of reasons, but they buy them for only one: they think the price will rise"
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- Peter Lynch
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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549 |
SCHEDULE 13G
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UNDER THE SECURITIES EXCHANGE ACT OF 1934
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(Amendment No. 1)*
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Mereo BioPharma Group plc (Name of Issuer) |
Ordinary Shares (Title of Class of Securities) |
(CUSIP Number) |
03/31/2026 (Date of Event Which Requires Filing of this Statement) |
| Check the appropriate box to designate the rule pursuant to which this Schedule is filed: |
 Rule 13d-1(b)
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| Rule 13d-1(c)
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 Rule 13d-1(d)
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SCHEDULE 13G
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| CUSIP No. |
| 1 | Names of Reporting Persons
EcoR1 Capital, LLC | ||||||||
| 2 | Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
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| 3 | Sec Use Only | ||||||||
| 4 | Citizenship or Place of Organization
DELAWARE
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| Number of Shares Beneficially Owned by Each Reporting Person With: |
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| 9 | Aggregate Amount Beneficially Owned by Each Reporting Person
66,844,275.00 | ||||||||
| 10 | Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
| ||||||||
| 11 | Percent of class represented by amount in row (9)
8.4 % | ||||||||
| 12 | Type of Reporting Person (See Instructions)
IA, OO |
Comment for Type of Reporting Person: These Ordinary Shares are held through 13,368,855 American Depositary Shares of the Issuer, each representing 5 Ordinary Shares. Percentage calculated based on 798,078,829 Ordinary Shares outstanding on March 18, 2026, as reported in the Form 10-K filed by the Issuer for the fiscal year ended December 31, 2025.
SCHEDULE 13G
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| CUSIP No. |
| 1 | Names of Reporting Persons
Oleg Nodelman | ||||||||
| 2 | Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
| ||||||||
| 3 | Sec Use Only | ||||||||
| 4 | Citizenship or Place of Organization
UNITED STATES
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| Number of Shares Beneficially Owned by Each Reporting Person With: |
| ||||||||
| 9 |
Aggregate Amount Beneficially Owned by Each Reporting Person
66,844,275.00 | ||||||||
| 10 | Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
| ||||||||
| 11 | Percent of class represented by amount in row (9)
8.4 % | ||||||||
| 12 | Type of Reporting Person (See Instructions)
HC, IN |
Comment for Type of Reporting Person: These Ordinary Shares are held through 13,368,855 American Depositary Shares of the Issuer, each representing 5 Ordinary Shares. Percentage calculated based on 798,078,829 Ordinary Shares outstanding on March 18, 2026, as reported in the Form 10-K filed by the Issuer for the fiscal year ended December 31, 2025.
SCHEDULE 13G
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| CUSIP No. |
| 1 | Names of Reporting Persons
EcoR1 Capital Fund Qualified, L.P. | ||||||||
| 2 | Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
| ||||||||
| 3 | Sec Use Only | ||||||||
| 4 | Citizenship or Place of Organization
DELAWARE
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| Number of Shares Beneficially Owned by Each Reporting Person With: |
| ||||||||
| 9 | Aggregate Amount Beneficially Owned by Each Reporting Person
62,644,610.00 | ||||||||
| 10 | Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
| ||||||||
| 11 | Percent of class represented by amount in row (9)
7.8 % | ||||||||
| 12 | Type of Reporting Person (See Instructions)
PN |
Comment for Type of Reporting Person: These Ordinary Shares are held through 12,528,922 American Depositary Shares of the Issuer, each representing 5 Ordinary Shares. Percentage calculated based on 798,078,829 Ordinary Shares outstanding on March 18, 2026, as reported in the Form 10-K filed by the Issuer for the fiscal year ended December 31, 2025.
SCHEDULE 13G
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| Item 1. | ||
| (a) | Name of issuer:
Mereo BioPharma Group plc | |
| (b) | Address of issuer's principal executive offices:
ONE CAVENDISH PLACE, FOURTH FLOOR, LONDON, United Kingdom, W1G 0QF | |
| Item 2. | ||
| (a) | Name of person filing:
EcoR1 Capital, LLC, a Delaware limited liability company ("EcoR1") EcoR1 Capital Fund Qualified, L.P., a Delaware limited partnership ("Qualified Fund") Oleg Nodelman Qualified Fund is filing this statement jointly with the other reporting persons, but not as a member of a group, and it expressly disclaims membership in a group. In addition, the filing of this Schedule 13G on behalf of Qualified Fund should not be construed as an admission that it is, and it disclaims that it is, a beneficial owner, as defined in Rule 13d-3 under the Act, of any securities covered by this Schedule 13G. Each reporting person also disclaims beneficial ownership of the securities reported herein except to the extent of that person's pecuniary interest therein. | |
| (b) | Address or principal business office or, if none, residence:
357 Tehama Street #3 San Francisco, CA 94103 | |
| (c) | Citizenship:
See Item 4 of the cover sheet for each reporting person. | |
| (d) | Title of class of securities:
Ordinary Shares | |
| (e) | CUSIP No.:
| |
| Item 3. | If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a: | |
| (a) | Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
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| (b) | Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
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| (c) | Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
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| (d) | Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
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| (e) | An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
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| (f) | An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
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| (g) | A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
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| (h) | A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
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| (i) | A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
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| (j) | A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution: | |
| (k) | Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
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| Item 4. | Ownership | |
| (a) | Amount beneficially owned:
EcoR1: 66,844,275 Oleg Nodelman: 66,844,275 Qualified Fund: 62,644,610 | |
| (b) | Percent of class:
EcoR1: 8.4% Oleg Nodelman: 8.4% Qualified Fund: 7.8% %
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| (c) | Number of shares as to which the person has:
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| (i) Sole power to vote or to direct the vote:
EcoR1: 0 Oleg Nodelman: 0 Qualified Fund: 0 | ||
| (ii) Shared power to vote or to direct the vote:
EcoR1: 66,844,275 Oleg Nodelman: 66,844,275 Qualified Fund: 62,644,610 | ||
| (iii) Sole power to dispose or to direct the disposition of:
EcoR1: 0 Oleg Nodelman: 0 Qualified Fund: 0 | ||
| (iv) Shared power to dispose or to direct the disposition of:
EcoR1: 66,844,275 Oleg Nodelman: 66,844,275 Qualified Fund: 62,644,610 | ||
| Item 5. | Ownership of 5 Percent or Less of a Class. | |
| Item 6. | Ownership of more than 5 Percent on Behalf of Another Person. | |
Not Applicable
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| Item 7. | Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person. | |
Not Applicable
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| Item 8. | Identification and Classification of Members of the Group. | |
If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group.
EcoR1 is the general partner and investment adviser of investment funds, including Qualified Fund. Mr. Nodelman is the control person of EcoR1. | ||
| Item 9. | Notice of Dissolution of Group. | |
Not Applicable
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| Item 10. | Certifications: |
By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect
, other than activities solely in connection with a nomination under ?? 240.14a-11. By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. |
| SIGNATURE | |
After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.
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Exhibit Information
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EXHIBIT 99 - AGREEMENT REGARDING JOINT FILING OF STATEMENT ON SCHEDULE 13D OR 13G |