Mereo BioPharma Group plc - Ordinary Shares (MREO) Institutional Ownership

13F Institutional Holders and Ownership History from Q2 2019 to Q4 2025

Type / Class
Equity / Ordinary Shares
Symbol
MREO on Nasdaq
Shares outstanding
792,553,191
Price per share
$0.42
All holders as of 30 Sep 2025
Q3 2025
Total 13F shares
99,471,712
Total reported value
$204,984,259
% of total 13F portfolios
0%
Share change
+1,589,446
Value change
-$1,639,628
Number of holders
82
Reported Shares, Excluding Options vs Price
Reported Value, Excluding Options
Total Investors

Significant Owners of Mereo BioPharma Group plc - Ordinary Shares (MREO) based on Schedule 13D/G filings

Filer Ownership Change % Holdings Value Net Change Nb Shares Change % Reporting Name Report Period
EcoR1 Capital, LLC 9.4% $31,044,150 74,500,000 EcoR1 Capital, LLC 02 Jan 2026
683 Capital Management, LLC 8.2% $27,120,426 65,083,815 683 Capital Management, LLC 29 Dec 2025
Northpond Ventures, LP 6.9% $136,302,500 54,521,000 Michael P. Rubin 04 Jun 2025
ADAGE CAPITAL PARTNERS GP, L.L.C. 5.6% $84,971,377 43,575,065 Adage Capital Management, L.P. 31 Dec 2024
MANGROVE PARTNERS IM, LLC 4.9% $80,242,974 38,952,900 Mangrove Partners IM, LLC 30 Sep 2025
Rock Springs Capital Management LP 4.2% $65,171,408 33,421,235 Rock Springs Capital Management LP 31 Mar 2025
Frazier Life Sciences Public Fund, L.P. 4.1% -20% $56,753,708 -$13,857,594 32,430,690 -20% Frazier Life Sciences Public Fund, L.P. 30 Jun 2025
JANUS HENDERSON GROUP PLC 10% -8.2% $33,557,668 -$2,880,832 16,290,130 -7.9% JANUS HENDERSON GROUP PLC 30 Sep 2025
Adage Capital Management, L.P. 1.1% $16,582,371 8,503,780 Adage Capital Management, L.P. 31 Mar 2025

As of 30 Sep 2025, 82 institutional investors reported holding 99,471,712 shares of Mereo BioPharma Group plc - Ordinary Shares (MREO). This represents 13% of the company’s total 792,553,191 outstanding shares.

Top 25 Institutional Shareholders

The largest institutional shareholders of Mereo BioPharma Group plc - Ordinary Shares (MREO) together control 12% of the company’s outstanding shares — a level of ownership often associated with strong institutional conviction and long‑term capital commitment.

Institution Ownership % Shares Held Share Change % Portfolio % Holdings Value
JANUS HENDERSON GROUP PLC 2.1% 16,290,130 -7.9% 0.02% $33,639,118
Rubric Capital Management LP 1.9% 15,307,347 0% 0.42% $31,533,135
Frazier Life Sciences Management, L.P. 1.2% 9,440,112 0% 0.58% $19,446,631
MANGROVE PARTNERS IM, LLC 0.98% 7,790,580 -9.8% 1.2% $16,048,595
Aberdeen Group plc 0.7% 5,538,699 +83% 0.02% $11,409,720
683 Capital Management, LLC 0.62% 4,875,000 +12% 0.91% $10,042,500
Rock Springs Capital Management LP 0.58% 4,570,649 +2.4% 0.55% $9,415,537
Clearline Capital LP 0.48% 3,834,163 +6% 0.68% $7,898,376
ALKEON CAPITAL MANAGEMENT LLC 0.47% 3,698,100 -21% 0.03% $7,618,086
MORGAN STANLEY 0.42% 3,346,347 +326% 0% $6,893,476
CITADEL ADVISORS LLC 0.4% 3,171,632 +317% 0.01% $6,533,561
GOLDMAN SACHS GROUP INC 0.3% 2,364,024 -23% 0% $4,869,889
Tejara Capital Ltd 0.24% 1,906,844 -22% 2.2% $3,928,099
UBS AM, A DISTINCT BUSINESS UNIT OF UBS ASSET MANAGEMENT AMERICAS LLC 0.24% 1,906,775 0% $3,927,957
Schonfeld Strategic Advisors LLC 0.22% 1,732,724 +90% 0.02% $3,569,409
FMR LLC 0.18% 1,454,900 -1.6% 0% $2,997,094
Blue Owl Capital Holdings LP 0.16% 1,250,000 0.8% $2,575,000
TWO SIGMA INVESTMENTS, LP 0.14% 1,088,096 +65% 0% $2,241,478
UBS Group AG 0.12% 970,667 +160% 0% $1,999,574
Monaco Asset Management SAM 0.12% 945,915 +139% 0.73% $1,948,585
MARSHALL WACE, LLP 0.1% 767,744 0% 0% $1,581,553
RENAISSANCE TECHNOLOGIES LLC 0.07% 590,871 -60% 0% $1,217,194
Logos Global Management LP 0.06% 500,000 0.1% $1,030,000
SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.06% 493,378 +36% 0% $1,016,359
Artia Global Partners LP 0.06% 475,361 0% 0.17% $979,244

Institutional Holders of Mereo BioPharma Group plc - Ordinary Shares (MREO) across Reporting Periods

Period Reported Shares, Excl. Options Value, Excl. Options Value Change Price (Median) Investors
2025 Q4 67,250 $28,023 -$11,505,046 $0.42 4
2025 Q3 99,471,712 $204,984,259 -$1,639,628 $2.06 82
2025 Q2 98,647,167 $267,511,231 -$28,666,972 $2.71 85
2025 Q1 110,598,225 $250,098,919 -$12,622,882 $2.25 87
2024 Q4 115,193,969 $403,099,510 +$29,662,669 $3.50 90
2024 Q3 105,735,860 $434,698,726 +$21,814,015 $4.11 76
2024 Q2 100,520,356 $361,910,507 +$59,870,789 $3.60 76
2024 Q1 84,006,001 $277,272,467 +$15,161,711 $3.30 77
2023 Q4 78,479,130 $181,284,350 +$12,810,156 $2.31 59
2023 Q3 69,934,611 $90,216,596 +$9,900,669 $1.29 52
2023 Q2 63,630,062 $83,982,713 +$2,509,054 $1.32 48
2023 Q1 60,813,068 $42,992,107 -$704,957 $0.71 56
2022 Q4 61,430,155 $46,072,279 -$7,729,931 $0.75 56
2022 Q3 67,994,550 $58,546,462 -$7,128,663 $0.86 56
2022 Q2 73,625,094 $82,466,840 -$16,891,771 $1.12 58
2022 Q1 88,907,613 $99,569,590 -$3,071,620 $1.12 55
2021 Q4 90,856,815 $145,372,152 -$12,171,049 $1.60 67
2021 Q3 87,503,716 $211,763,957 -$26,637,495 $2.42 57
2021 Q2 89,643,611 $284,080,000 -$2,185,467 $3.17 68
2021 Q1 90,227,108 $304,107,740 +$110,553,537 $3.37 65
2020 Q4 57,137,622 $204,525,659 +$140,020,305 $3.58 42
2020 Q3 14,273,644 $37,396,668 +$17,967,004 $2.62 20
2020 Q2 7,273,442 $22,258,000 +$12,817,117 $3.06 18
2020 Q1 1,400 $1,000 -$469,181 $0.71 1
2019 Q4 1,234,966 $4,050,000 -$2,321,199 $3.28 8
2019 Q3 1,755,706 $5,132,000 -$79,373 $2.94 12
2019 Q2 1,722,410 $4,189,000 +$4,189,016 $2.44 13