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Equibles

MREO

Mereo BioPharma Group plc

Company with tickers: MREO

CIK
1719714
CUSIP
589492107
Shares Outstanding
159,618,609
13F Activity (30d)
50 filings 48 filers

Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.

Holders: 64
Total Value: $25,171,423
Total Shares: 76,277,137

Institutional Ownership Trend

25 quarters

Holder Concentration

Across 64 13F filers · Δ vs Dec 31, 2025
Top Holder
20.1%
Jun 2023 → Mar 2026 · range 14.4% – 22.9%
−2.9 pts
Top 5
74.0%
Jun 2023 → Mar 2026 · range 51.3% – 74.0%
+4.4 pts
Top 10
93.6%
Jun 2023 → Mar 2026 · range 72.8% – 93.6%
+10.9 pts
HHI
1,294
Jun 2023 → Mar 2026 · range 710 – 1,316
Broadly held −23

Quarterly Activity

vs Dec 31, 2025
New
15
Increased
15
Decreased
18
Sold Out
24
Unchanged
16
Holder count: -9
Institutional value: -9.6%
Shares held: +14.3%

Top Buyers

vs Dec 31, 2025
Institution Added Now Holds Open
Mega BANK OF AMERICA CORP /DE/ +8,169,795 8,195,287
Small Newtyn Management, LLC +6,854,434 7,079,056
Mid EcoR1 Capital, LLC +5,512,389 13,368,855
Mega MILLENNIUM MANAGEMENT LLC +3,475,457 3,559,103
Large ACADIAN ASSET MANAGEMENT LLC +147,649 209,084

Top Sellers

vs Dec 31, 2025
Institution Sold Now Holds Open
Mid 683 Capital Management, LLC −3,025,000 12,000,000
Mega MORGAN STANLEY −1,257,360 16,425
Mega JANE STREET GROUP, LLC −539,931 333,773
Mega TWO SIGMA INVESTMENTS, LP −337,286 187,839
Mega CITADEL ADVISORS LLC −293,900 454,800

Top New Positions

vs Dec 31, 2025
Institution Acquired Value (USD) Open
Small Defilade Capital Management, L.P. 7,558,756 $2,494,389
Mid Wealthspire Advisors, LLC 796,036 $262,691
Large MARSHALL WACE, LLP 686,987 $226,705
Mid XTX Topco Ltd 84,469 $27,874
Small StoneX Group Inc. 36,873 $12,168

Top Sold-Out Positions

vs Dec 31, 2025
Institution Previously Held Last Value (USD) Open
Large Schonfeld Strategic Advisors LLC 6,090,381 $2,539,688
Small DIADEMA PARTNERS LP 1,999,500 $833,791
Mid Logos Global Management LP 1,850,000 $771,450
Mega UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC 1,763,666 $735,448
Small Monaco Asset Management SAM 1,585,214 $661,034
Filter: New 15 Increased 15 Reduced 18 Sold out 24 Unchanged 16
Showing 69 of 69
All Common Calls Puts
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Holder Value (USD) % of 13F Shares Open
Mid Rubric Capital Management LP $5,051,424 20.07% 15,307,347
Mid EcoR1 Capital, LLC $4,411,722 17.53% 13,368,855
Mid 683 Capital Management, LLC $3,960,000 15.73% 12,000,000
Mega BANK OF AMERICA CORP /DE/ Bank $2,704,444 10.74% 8,195,287
Small Defilade Capital Management, L.P. $2,494,389 9.91% 7,558,756
Small Newtyn Management, LLC $2,336,088 9.28% 7,079,056
Mega MILLENNIUM MANAGEMENT LLC $1,174,503 4.67% 3,559,103
Small Tejara Capital Ltd $672,381 2.67% 2,037,520
Mega UBS Group AG $491,739 1.95% 1,490,128
Mid Wealthspire Advisors, LLC $262,691 1.04% 796,036
Large MARSHALL WACE, LLP $226,705 0.90% 686,987
Mega CITADEL ADVISORS LLC $127,710 0.51% 387,000
Mid GROUP ONE TRADING LLC $110,822 0.44% 335,827
Small Rangeley Capital, LLC $108,636 0.43% 329,200
Mega BlackRock, Inc. $99,986 0.40% 302,991
Small Knott David M Jr $99,111 0.39% 300,337
Large ACADIAN ASSET MANAGEMENT LLC $68,997 0.27% 209,084
Mega SUSQUEHANNA INTERNATIONAL GROUP, LLP $67,188 0.27% 203,600
Mega SUSQUEHANNA INTERNATIONAL GROUP, LLP $64,652 0.26% 195,920
Mega TWO SIGMA INVESTMENTS, LP $61,986 0.25% 187,839
Mid ADAR1 Capital Management, LLC $49,500 0.20% 150,000
Mega JANE STREET GROUP, LLC $46,189 0.18% 139,973
Mega STATE STREET CORP $44,015 0.17% 133,379
Micro Forefront Analytics, LLC $42,166 0.17% 127,778
Small Virtus Investment Advisers, LLC $41,468 0.16% 125,662
Mega JANE STREET GROUP, LLC $37,026 0.15% 112,200
Mega GEODE CAPITAL MANAGEMENT, LLC $30,536 0.12% 92,534
Mid XTX Topco Ltd $27,874 0.11% 84,469
Mega JANE STREET GROUP, LLC $26,928 0.11% 81,600
Mega CITADEL ADVISORS LLC $22,374 0.09% 67,800
Large Caption Management, LLC $21,141 0.08% 64,064
Small SmartHarvest Portfolios, LLC $16,338 0.06% 49,512
Large RENAISSANCE TECHNOLOGIES LLC $15,972 0.06% 48,400
Mega SUSQUEHANNA INTERNATIONAL GROUP, LLP $14,652 0.06% 44,400
Small StoneX Group Inc. $12,168 0.05% 36,873
Mid Virtu Financial LLC $12,031 0.05% 36,458
Mid Independent Advisor Alliance $11,624 0.05% 35,227
Mid Clear Harbor Asset Management, LLC $11,550 0.05% 35,000
Micro Significant Wealth Partners LLC $8,459 0.03% 25,634
Large Centiva Capital, LP $8,250 0.03% 25,000
Mid Engineers Gate Manager LP $7,904 0.03% 23,954
Mega JPMORGAN CHASE & CO $7,209 0.03% 21,848
Mega RHUMBLINE ADVISERS $6,458 0.03% 19,572
Mid GAMMA Investing LLC $6,360 0.03% 19,274
Micro Three Magnolias Financial Advisors, LLC $6,270 0.02% 19,000
Small NFSG Corp $6,187 0.02% 18,750
Mid OneDigital Investment Advisors LLC $6,039 0.02% 18,300
Mega MORGAN STANLEY $5,419 0.02% 16,425
Mid IHT Wealth Management, LLC $4,950 0.02% 15,000
Mid Baader Bank Aktiengesellschaft Bank $4,068 0.02% 12,330
Large MML INVESTORS SERVICES, LLC $4,026 0.02% 12,200
Mid World Investment Advisors $3,300 0.01% 10,000
Small Astoria Portfolio Advisors LLC. $3,300 0.01% 10,000
Mid Arax Advisory Partners $1,320 0.01% 4,000
Mega BARCLAYS PLC $823 0.00% 2,496
Large Rockefeller Capital Management L.P. $660 0.00% 2,000
Large OSAIC HOLDINGS, INC. $495 0.00% 1,500
Mid Allworth Financial LP $495 0.00% 1,500
Mid SIT INVESTMENT ASSOCIATES INC $320 0.00% 970
Mid MAI Capital Management $101 0.00% 309
Micro New England Capital Financial Advisors LLC $99 0.00% 300
Mega WELLS FARGO & COMPANY/MN $75 0.00% 230
Mid SBI Securities Co., Ltd. Broker-Dealer $37 0.00% 114
Mid EverSource Wealth Advisors, LLC $33 0.00% 100
Mid Sound Income Strategies, LLC $21 0.00% 66
Large NATIONAL BANK OF CANADA /FI/ Bank $15 0.00% 46
Large US BANCORP \DE\ Bank $4 0.00% 13
Small Axiom Investment Management LLC $0 0.00% 1
Mega BNP PARIBAS ARBITRAGE, SA $0 0.00% 3

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