MREO · Mereo BioPharma Group plc · Holdings

$0.29 0.00 (-1.32%) At close · Oct 21

Market Cap

$47.12M

159.69M

Volume · Oct 21 330.19K Avg daily vol (3M) 3.99M

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.

Use institutional holdings through the 13F API or MCP → See every holder of MREO: 13F, 13D and 13G, insiders and funds →

Institutional holdings are being reconciled with SEC filings. Holder totals and changes may be incomplete until reconciliation finishes.

The Sep 30, 2026 filing window is still open — showing the latest known positions. Funds that have not filed yet carry their prior-quarter positions; a fund that filed without this stock counts as sold out. Each fund's Change is measured against its own previous reported quarter, shown in the Reported column. Pick a completed quarter in the Quarter selector below to put every fund on one quarter and see the stock-wide activity breakdown.

Quarter:

Holders: 60

Total Value: $18,253,214

Total Shares: 57,394,648

Institutional Ownership Trend

27 quarters

Holder Concentration

Across 60 13F filers

Top Holder

26.7%

of institutional value

Top 5

79.9%

of institutional value

Top 10

91.7%

of institutional value

HHI

1,574

Moderately concentrated

Who Holds MREO

Last 8 quarters through Sep 30, 2026 (filing window open)

Each kind of 13F filer's share of the common shares 13F filers report. Holder type comes from regulatory records, never the filer's name; style, turnover and horizon are measured from each filer's own 13F book. The quarter selector does not change this card.

Jun 30, 2026, the newest closed quarter: 60 filers, like-for-like change -24.9%; actively managed books -24.8%; index-like books -41.4%.

Holder type	Share	Filers	Change	New	Exited
Registered adviser	75.4%	29	-30.0%	4	9
Exempt adviser	3.9%	2	-18.6%	0	0
Bank	17.4%	7	-0.1%	1	2
Broker-dealer	0.3%	1	-50.1%	0	0
Non-US	0.0%	2	0.0%	0	0
Holding company	0.3%	4	-46.1%	1	0
Adviser	0.0%	0	—	0	0
Unknown	2.7%	15	+26.1%	7	6

Style	Share	Filers	Change	New	Exited
Index-like	0.6%	6	-41.4%	1	1
Systematic-like	4.1%	7	-52.4%	2	1
Concentrated	8.7%	8	-77.3%	1	3
Diversified active	86.6%	39	+1.7%	9	12
Not measured	0.0%	0	—	0	0
Unknown	0.0%	0	—	0	0

Turnover	Share	Filers	Change	New	Exited
Low turnover	16.8%	23	-5.0%	2	6
Medium turnover	58.5%	17	-34.2%	4	8
High turnover	9.8%	15	-24.8%	5	2
Unknown	14.8%	5	+10.5%	2	1
Not measured	0.0%	0	—	0	0

Holding horizon	Share	Filers	Change	New	Exited
Short horizon	15.8%	9	+10.4%	3	2
Medium horizon	4.1%	11	-23.4%	3	4
Long horizon	23.9%	32	-52.7%	6	11
Unknown	56.1%	8	-10.8%	1	0
Not measured	0.0%	0	—	0	0

13F book size	Share	Filers	Change	New	Exited
Under $1B	24.8%	15	-20.7%	5	5
$1B to $10B	23.6%	18	-49.1%	3	6
$10B to $100B	29.0%	11	-3.7%	1	2
$100B or more	22.6%	16	-10.9%	4	4
Not measured	0.0%	0	—	0	0

Client base	Share	Filers	Change	New	Exited
Individuals and high net worth	1.8%	12	+6.4%	2	4
Pooled investment vehicles	73.4%	11	-30.3%	2	3
Registered funds and BDCs	0.0%	1	-99.6%	0	2
Pension and profit sharing plans	0.0%	2	0.0%	0	0
Governments and sovereign funds	0.0%	1	+36.8%	0	0
Other investment advisers	0.0%	1	-51.7%	0	0
Diversified	0.0%	1	0.0%	0	0
Corporations	0.0%	0	—	0	0
Unknown	24.6%	31	-3.6%	9	8

Private funds	Share	Filers	Change	New	Exited
Hedge funds	77.4%	14	-29.8%	2	3
Private equity funds	0.0%	0	—	0	0
Real estate funds	0.0%	2	+34.2%	0	1
Other private funds	0.1%	3	+32.0%	0	0
No private funds	1.8%	12	-13.7%	2	5
Securitized asset funds	0.0%	0	—	0	0
Mixed private funds	0.0%	0	—	0	0
Private funds, type not stated	0.0%	0	—	0	0
Unknown	20.7%	29	-0.1%	9	8

Location	Share	Filers	Change	New	Exited
United States	93.0%	52	-25.9%	10	14
Outside the US	7.0%	8	-8.3%	3	3

The Sep 30, 2026 filing window is still open, so its bar carries the Jun 30, 2026 positions of filers that have not filed yet.

How the mix is measured

Shares are 13F common shares restated to today's split basis; options and principal amounts are left out. The change compares only filers with a 13F in both quarters and keeps each filer in its bucket of the later quarter on both sides; a filer that continues under a new CIK is compared through its successor. Holder type comes from each filer's current regulatory profile; client base and private funds come from the Form ADV roster current at each quarter end (rosters from December 2019, so an earlier quarter reads Unknown). Style, turnover, horizon and book size are measured from each filer's 13F book in the newest measured quarter, and Not measured means none was. Actively managed books are those measured systematic-like, concentrated or diversified active.

Excluded 1 holder with no observed 2026-03-31 13F.

Conviction and Crowding

60 13F filers, quarter ended Jun 30, 2026

Measured across every 13F filer's common-share book once the quarter's filing window closed. Crowding counts filers with high turnover or that advise private funds on Form ADV.

Conviction holders

0.000% of filers hold it in their top 10

Mar 31, 2026: 0

Holders above 5%

median weight 0.000%

Mar 31, 2026: 0

Crowding

5.69%

of shares outstanding, 18th percentile

Mar 31, 2026: 7.93%

Private-fund advisers

5.50%

of shares outstanding

Institutional ownership

7.09%

7.10% of the estimated free float

Top 10 holders

92.6%

of 13F shares, Herfindahl 0.161

Active holders

-24.8%

like-for-like share change of active filers

5% stakes on record

1 13D, 2 13G (1 institutional, 1 passive, 0 exempt)

How long holders have held it value-weighted 15.0 quarters

Under 1 year 26.7% 1 to 3 years 4.70% 3 years or more 68.6% Since coverage start 0.000%

Managers in the top fifth by current three-year FundScore alpha were net buyers of $0 (0 buying, 0 selling).

Estimated Holder Cost Basis

Quarter ended Jun 30, 2026, on that quarter's share basis

Estimated, never filed: each 13F buy is costed at its quarter's average traded price and each sale keeps the average cost, so this is what holders paid on average if they traded evenly through each quarter.

Estimated avg cost

$1.51

estimated per share

Mar 31, 2026: $1.43

Quarter-end price

$0.32

implied by 13F values

Estimated gain or loss

-78.9%

price against the estimated cost

Estimated at a loss

96.3%

of costed 13F value

Estimated cost covers 81.9% of the 13F shares; positions already held when a filer's 13F history starts, or bought in a quarter without a trusted average price, have no estimate.

Shared Holders

Companies MREO's active holders also own, quarter ended Jun 30, 2026

#	Company	Shared holders	Similarity
1	WVE Wave Life Sciences, Inc.	4	0.261
2	ENOV Enovis CORP	3	0.236
3	QDEL QuidelOrtho Corp	3	0.229
4	ORIC Oric Pharmaceuticals, Inc.	3	0.183
5	SPRY ARS Pharmaceuticals, Inc.	3	0.177
6	INSM INSMED Inc	3	0.099
7	AMZN Amazon Com Inc	4	0.017
8	AMD Advanced Micro Devices Inc	3	0.017
9	GOOGL Alphabet Inc.	3	0.013

Shareholder Targets

13F filers that own its peers but not MREO, quarter ended Jun 30, 2026

Found through its holder-overlap peers: WVE, ENOV, QDEL, ORIC, SPRY, INSM, AMZN, AMD, GOOGL. 6,827 filers in all.

#	Filer	In peers	Of book	Largest peers
1	VANGUARD CAPITAL MANAGEMENT LLC Registered adviser, Index-like	$459,923,012,795 9 held	9.80%	GOOGL, AMZN, AMD
2	FMR LLC Holding company, Diversified active	$237,125,120,055 9 held	10.5%	GOOGL, AMZN, AMD
3	GEODE CAPITAL MANAGEMENT, LLC Registered adviser, Index-like	$173,328,921,454 9 held	9.21%	GOOGL, AMZN, AMD
4	Invesco Ltd. Adviser, Diversified active	$121,308,950,015 9 held	9.61%	GOOGL, AMZN, AMD
5	VANGUARD PORTFOLIO MANAGEMENT LLC Registered adviser, Diversified active	$115,447,280,932 9 held	5.19%	GOOGL, AMZN, AMD
6	PRICE T ROWE ASSOCIATES INC /MD/ Registered adviser, Diversified active	$104,428,060,328 9 held	10.6%	GOOGL, AMZN, AMD
7	NORGES BANK Non-US, Index-like	$102,780,842,936 4 held	10.2%	GOOGL, AMZN, AMD
8	NORTHERN TRUST CORP Bank, Index-like	$74,321,634,313 9 held	8.97%	GOOGL, AMZN, AMD
9	Capital Research Global Investors Adviser, Diversified active	$68,729,848,741 3 held	9.54%	GOOGL, AMZN, AMD
10	Capital World Investors Adviser, Diversified active	$59,737,337,836 4 held	7.08%	GOOGL, AMZN, AMD

Fund Ownership of MREO by Fund Type

Registered funds' Form N-PORT reports for the quarter ended Jun 30, 2026

Index funds and index ETFs hold 0.37% of shares outstanding.

Fund type	Of shares outstanding	Change	Shares	Funds
Index funds	0.06%	0.00 pp	92,534	1
Index ETFs	0.31%	+0.01 pp	494,603	3
Active ETFs	0.00%	0.00 pp	0	0
Active funds	0.01%	+0.01 pp	14,500	1
Unclassified	0.00%	0.00 pp	0	0
All registered funds	0.38%	+0.02 pp	601,637	5

How fund types are measured

Each fund series counts once, with its latest Form N-PORT report dated inside the quarter; only long share positions count, restated to today's split basis. The fund type is the series' latest Form N-CEN answer on or before the quarter end (the index-fund box and the exchange-traded flag), never its name. Unclassified funds have no usable N-CEN; unit investment trusts are among them, so index ownership is a floor. Funds sit inside their advisers' 13F reports, so these shares overlap the 13F figures and are never added to them.

Holder type: Registered adviser 29 Exempt adviser 2 Bank 7 Broker-dealer 1 Non-US 2 Holding company 4 Unknown 15

Showing 65 of 65

All Common Calls Puts

Compact Export CSV

Holder

Value (USD)

% of 13F

Rubric Capital Management LP

$4,867,736

26.67%

15,307,347

683 Capital Management, LLC

$3,745,358

20.52%

11,777,856

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
683 Capital Partners, LP	11,777,856	$3,745,358	100.0%	Defined

BANK OF AMERICA CORP /DE/

$2,606,099

14.28%

8,195,281

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
BOFA SECURITIES, INC.	8,195,281	$2,606,099	100.0%	Defined

Defilade Capital Management, L.P.

$2,403,684

13.17%

7,558,756

Newtyn Management, LLC

$954,000

5.23%

3,000,000

Tejara Capital Ltd

$647,931

3.55%

2,037,520

UBS Group AG

$460,344

2.52%

1,447,627

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
UBS Financial Services Inc	5,912	$1,880	0.4%	Defined
UBS AG	1,344,248	$427,470	92.9%	Defined
UBS Securities LLC	97,467	$30,994	6.7%	Defined

TWO SIGMA INVESTMENTS, LP

$419,518

2.30%

1,319,241

EcoR1 Capital, LLC

$318,000

1.74%

1,000,000

JANE STREET GROUP, LLC

$246,431

1.35%

774,944

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Jane Street Capital, LLC	486,971	$154,856	62.8%	Defined
Jane Street Global Trading, LLC	287,973	$91,575	37.2%	Defined

Ishara Investments LP

$244,462

1.34%

768,750

Wealthspire Advisors, LLC

$243,270

1.33%

765,000

CITADEL ADVISORS LLC

$160,558

0.88%

504,900

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citadel Securities GP LLC	504,900	$160,558	100.0%	Defined

CITADEL ADVISORS LLC

$141,242

0.77%

444,158

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citadel Securities GP LLC	430,780	$136,988	97.0%	Defined
Held directly	13,378	$4,254	3.0%	Defined

Rangeley Capital, LLC

$104,685

0.57%

329,200

SUSQUEHANNA INTERNATIONAL GROUP, LLP

$67,819

0.37%

213,270

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SUSQUEHANNA SECURITIES, LLC	213,270	$67,819	100.0%	Other

MARSHALL WACE, LLP

$57,202

0.31%

179,884

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Marshall Wace North America L.P. joint	179,884	$57,202	100.0%	Other

XTX Topco Ltd

$55,484

0.30%

174,481

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
XTX EXECUTION SERVICES LLC joint	174,481	$55,484	100.0%	Defined

SUSQUEHANNA INTERNATIONAL GROUP, LLP

$55,173

0.30%

173,500

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SUSQUEHANNA SECURITIES, LLC	173,500	$55,173	100.0%	Other

GROUP ONE TRADING LLC

$53,269

0.29%

167,515

STATE STREET CORP

$42,857

0.23%

134,772

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SSGA FUNDS MANAGEMENT, INC.	134,772	$42,857	100.0%	Defined

NOMURA HOLDINGS INC

$33,186

0.18%

104,361

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
NOMURA SECURITIES INTERNATIONAL INC	104,361	$33,186	100.0%	Defined

James J. Burns & Company, LLC

$30,337

0.17%

95,400

Quarry LP

$29,812

0.16%

93,750

GOLDMAN SACHS GROUP INC

$27,087

0.15%

85,180

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
GOLDMAN SACHS & CO. LLC	85,180	$27,087	100.0%	Defined

JMN Financial LLC

$24,405

0.13%

76,748

BlackRock, Inc.

$22,157

0.12%

69,678

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Aperio Group, LLC	69,678	$22,157	100.0%	Sole

Virtu Financial LLC

$19,488

0.11%

61,285

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Virtu Americas LLC	61,285	$19,488	100.0%	Defined

JPMORGAN CHASE & CO

$18,612

0.10%

58,531

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
JPMorgan Chase Bank, N.A.	1,296	$412	2.2%	Defined
J.P. Morgan Securities LLC	56,923	$18,101	97.3%	Defined
J.P. Morgan Securities plc	312	$99	0.5%	Defined

RENAISSANCE TECHNOLOGIES LLC

$16,567

0.09%

52,100

CITADEL ADVISORS LLC

$16,218

0.09%

51,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citadel Securities GP LLC	51,000	$16,218	100.0%	Defined

SUSQUEHANNA INTERNATIONAL GROUP, LLP

$14,628

0.08%

46,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SUSQUEHANNA SECURITIES, LLC	46,000	$14,628	100.0%	Other

Significant Wealth Partners LLC

$10,391

0.06%

32,677

Clear Harbor Asset Management, LLC

$10,176

0.06%

32,000

RHUMBLINE ADVISERS

$8,517

0.05%

26,784

Centiva Capital, LP

$7,950

0.04%

25,000

Engineers Gate Manager LP

$7,617

0.04%

23,953

NFSG Corp

$7,537

0.04%

18,750

SIMPLEX TRADING, LLC

$5,972

0.03%

18,780

OneDigital Investment Advisors LLC

$5,819

0.03%

18,300

MORGAN STANLEY

$5,318

0.03%

16,731

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
MORGAN STANLEY & CO. LLC	172	$54	1.0%	Defined
MORGAN STANLEY CAPITAL SERVICES, LLC	14,006	$4,453	83.7%	Defined
MORGAN STANLEY SMITH BARNEY LLC	2,553	$811	15.3%	Defined

IHT Wealth Management, LLC

$4,770

0.03%

15,000

TWO SIGMA SECURITIES, LLC

$4,102

0.02%

12,900

J. Safra Sarasin Holding AG

$4,083

0.02%

12,841

SG Americas Securities, LLC

$4,071

0.02%

12,802

MML INVESTORS SERVICES, LLC

$3,879

0.02%

12,200

JANE STREET GROUP, LLC

$3,752

0.02%

11,800

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Jane Street Capital, LLC	11,800	$3,752	100.0%	Defined

World Investment Advisors

$3,180

0.02%

10,000

Astoria Portfolio Advisors LLC.

$3,180

0.02%

10,000

Arax Advisory Partners

$1,850

0.01%

5,819

GAMMA Investing LLC

$800

0.00%

1,991

Rockefeller Capital Management L.P.

$636

0.00%

2,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
ROCKEFELLER FINANCIAL LLC	2,000	$636	100.0%	Defined

Allworth Financial LP

$477

0.00%

1,500

OSAIC HOLDINGS, INC.

$477

0.00%

1,500

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
OSAIC WEALTH, INC.	1,000	$318	66.7%	Defined
Osaic Advisory Services, LLC	500	$159	33.3%	Defined

Markowski Investments

$477

0.00%

1,500

SIT INVESTMENT ASSOCIATES INC

$308

0.00%

970

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SIT FIXED INCOME ADVISORS II LLC /ADV	970	$308	100.0%	Sole

New England Capital Financial Advisors LLC

$95

0.00%

300

WELLS FARGO & COMPANY/MN

$73

0.00%

231

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
WELLS FARGO ADVISORS FINANCIAL NETWORK, LLC	1	$0	0.0%	Defined
WELLS FARGO CLEARING SERVICES, LLC	230	$73	100.0%	Defined

SBI Securities Co., Ltd.

$36

0.00%

114

EverSource Wealth Advisors, LLC

$31

0.00%

100

CITIGROUP INC

$16

0.00%

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citigroup Financial Products Inc. joint	52	$16	100.0%	Defined

US BANCORP \DE\

0.00%

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
US BANK NATIONAL ASSOCIATION	13	$4	100.0%	Defined

BNP PARIBAS ARBITRAGE, SA

0.00%

Axiom Investment Management LLC

0.00%

Caitong International Asset Management Co., Ltd

0.00%

Key facts CIK 1719714 CUSIP 589492107 13F (30d) 3 filings 3 filers Visit website Investor relations