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Livermore
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Mereo BioPharma Group plc

MREO
Exchange
Nasdaq
Industry
Pharmaceutical Preparations
SEC CIK
0001719714

No open-market purchases or sales by Mereo BioPharma Group plc insiders were filed in the last 90 days; 60 institutions reported holding it in 13F filings for Q2 2026, worth $18.0M in total; no superinvestor holds it.

Holders of 5% or more of MREO

Holders whose latest Schedule 13D or 13G filing reports 5% or more of Mereo BioPharma Group plc, largest stake first. The change is against the holder's previous filing.

Holders of 5% or more of MREO
HolderLatest formStakeChangeFirst filedLatest filingFiling
683 Capital Management, LLC13G8.18%65.1M sharesNewJan 6, 20261 filingJan 6, 2026SEC
Adage Capital Partners GP, L.L.C.13G/A5.62%43.6M shares–Feb 5, 20242 filingsFeb 12, 2025SEC
Bank of America Corp13G5.10%41.0M sharesNewMay 14, 20261 filingMay 14, 2026SEC

Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.

13D and 13G filings

65 Schedule 13D and 13G filings on Mereo BioPharma Group plc, newest first, including old-format filings without a stake.

Schedule 13D and 13G filings on MREO
Filed (ET)FilerFormStakeChangeEvent dateFiling
Aug 14, 202612:57 PM ETEcoR1 Capital, LLCand 2 others13G/A0.60%5.00M shares−7.80 ppfrom 8.40%Below 5%Jun 30, 2026SEC
May 15, 20262:25 PM ETEcoR1 Capital, LLCand 2 others13G/A8.40%66.8M shares−1.00 ppfrom 9.40%Mar 31, 2026SEC
May 14, 20263:07 PM ETBank of America Corp13G5.10%41.0M sharesNewMar 31, 2026SEC
Feb 17, 20266:49 PM ETNorthpond Ventures, LPand 6 others13G/A0.00%0 shares−6.90 ppfrom 6.90%Below 5%Dec 31, 2025SEC
Feb 17, 202612:34 PM ETJanus Henderson Group PLC13G/A0.00%0 shares−10.20 ppfrom 10.20%Below 5%Dec 31, 2025SEC
Feb 13, 20265:35 PM ETFrazier Life Sciences Public Fund, L.P.and 10 others13G/A0.00%0 shares−4.10 ppfrom 4.10%Below 5%Dec 31, 2025SEC
Jan 9, 20265:24 PM ETEcoR1 Capital, LLCand 2 others13G9.40%74.5M sharesNewJan 2, 2026SEC
Jan 6, 20265:38 PM ET683 Capital Management, LLCand 2 others13G8.18%65.1M sharesNewDec 29, 2025SEC
Nov 14, 202511:58 AM ETJanus Henderson Group PLCand 1 other13G/A10.20%16.3M shares−0.90 ppfrom 11.10%Sep 30, 2025SEC
Nov 14, 20259:16 AM ETMangrove Partnersand 1 other13G/A4.90%39.0M shares–Below 5%Sep 30, 2025SEC
Aug 14, 20251:39 PM ETFrazier Life Sciences Public Fund, L.P.and 16 others13G/A4.10%32.4M shares−1.00 ppfrom 5.10%Below 5%Jun 30, 2025SEC
Aug 14, 202511:15 AM ETJanus Henderson Group PLCand 1 other13G/A11.10%17.7M shares−3.20 ppfrom 14.30%Jun 30, 2025SEC
Jun 11, 20257:51 PM ETNorthpond Ventures, LPand 6 others13G6.90%54.5M sharesNewJun 4, 2025SEC
May 15, 202510:46 AM ETRock Springs Capital Management LPand 4 others13G/A4.20%33.4M shares–Below 5%Mar 31, 2025SEC
May 14, 20254:34 PM ETJanus Henderson Group PLCand 1 other13G/A14.30%22.7M shares+4.00 ppfrom 10.30%Mar 31, 2025SEC
May 12, 20259:01 AM ETAdage Capital Management, L.P.and 2 others13G/A1.07%8.50M shares–Below 5%Mar 31, 2025SEC
Apr 4, 202512:39 PM ETFrazier Life Sciences Public Fund, L.P.and 16 others13G5.10%40.3M sharesNewApr 1, 2025SEC
Feb 12, 20259:34 AM ETAdage Capital Partners GP, L.L.C.and 3 others13G/A5.62%43.6M shares–Dec 31, 2024SEC
Dec 6, 202411:37 AM ETJanus Henderson Group PLCand 1 other13G/A10.30%15.9M shares–Nov 29, 2024SEC
Feb 14, 2024Rock Springs Capital Management LP13G/AOld format–––SEC
Feb 14, 2024Rock Springs Capital Management LP13G/AOld format–––SEC
Feb 14, 2024Mangrove Partners13GOld format–New–SEC
Feb 14, 2024OrbiMed Advisors LLC13G/AOld format–––SEC
Feb 13, 2024Suvretta Capital Management, LLC13G/AOld format–––SEC
Feb 6, 2024Soleus Private Equity Fund III, L.P.13G/AOld format–––SEC
Feb 5, 2024Adage Capital Partners GP, L.L.C.13GOld format–New–SEC
Nov 20, 2023Rubric Capital Management LP13D/AOld format–––SEC
Nov 15, 2023Rubric Capital Management LP13D/AOld format–––SEC
Nov 13, 2023Rubric Capital Management LP13D/AOld format–––SEC
Nov 8, 2023Rubric Capital Management LP13D/AOld format–––SEC
Nov 6, 2023Rubric Capital Management LP13D/AOld format–––SEC
Nov 2, 2023Rubric Capital Management LP13D/AOld format–––SEC
Oct 31, 2023Rubric Capital Management LP13D/AOld format–––SEC
Aug 10, 2023Baker Bros. Advisors LP13G/AOld format–––SEC
Jul 26, 2023Soleus Private Equity Fund III, L.P.13GOld format–New–SEC
Jun 16, 2023Rubric Capital Management LP13D/AOld format–––SEC
Feb 14, 2023Vivo Capital IX, LLC13G/AOld format–––SEC
Feb 14, 2023Rock Springs Capital Management LP13G/AOld format–––SEC
Feb 14, 2023Baker Bros. Advisors LP13G/AOld format–––SEC
Feb 14, 2023OrbiMed Advisors LLC13G/AOld format–––SEC
Feb 14, 2023Point72 Asset Management, L.P.13G/AOld format–––SEC
Feb 13, 2023Suvretta Capital Management, LLC13G/AOld format–––SEC
Oct 28, 2022Rubric Capital Management LP13D/AOld format–––SEC
Sep 23, 2022Rubric Capital Management LP13D/AOld format–––SEC
Aug 24, 2022Rubric Capital Management LP13D/AOld format–––SEC
Jun 14, 2022Rubric Capital Management LP13D/AOld format–––SEC
Jun 9, 2022Rubric Capital Management LP13D/AOld format–––SEC
May 26, 2022Rubric Capital Management LP13DOld format–––SEC
Feb 15, 2022Rock Springs Capital Management LP13GOld format–New–SEC
Feb 14, 2022Boxer Capital, LLC13G/AOld format–––SEC

Form 144: proposed insider sales

Notices from officers, directors and other affiliates planning to sell Mereo BioPharma Group plc shares.

No Form 144 notices for Mereo BioPharma Group plc are on file.