MREO Mereo BioPharma Group plc

NASDAQ
$0.30

Mereo BioPharma Group plc (MREO) Hedge Fund Activity

This view isolates hedge funds from the broader institutional ownership shown on the Institutional tab. A pension fund tracking an index may have no view on a stock; when a hedge fund builds or exits a position, that decision can carry information. This page measures those changes. Positions as of June 30, 2026.

Based on quarterly 13F long-equity filings. Changes compare reported quarter-end positions; filings can be reported up to 45 days later and do not represent a fund's complete exposure.

Hedge fund breadth
-33.33
3 buyers / 6 sellers
STRONG SELLING
Funds compared
11
funds with comparable MREO positions
8 current holders · 10 prior-quarter holders
Net share change
-15.07M
+1.58M added, -16.65M cut
Position activity
1 new 2 increased 3 reduced 3 exited

Most significant moves

Ranked by conviction, not size — how much of the fund's own book the position represents, how far it moved, and what kind of fund made it.

Fund Action Shares changed Change Est. value Portfolio wt. Score
MILLENNIUM MANAGEMENT LLC Sold Out -3.56M -100.0% $1.1M 0.0% 59
CITADEL ADVISORS LLC Quant New +444.2K — $141.1K 0.0% 58
ADAR1 Capital Management Long/Short Growth Sold Out -150.0K -100.0% $47.7K 0.0% 53
TWO SIGMA INVESTMENTS, LP Quant Increased +1.13M +602.3% $359.4K 0.0% 51
EcoR1 Capital Growth Healthcare Reduced -12.37M -92.5% $3.9M 0.0% 50
Caption Management Quant Sold Out -64.1K -100.0% $20.4K 0.0% 50
MARSHALL WACE, LLP Long/Short Reduced -507.1K -73.8% $161.1K 0.0% 44
RENAISSANCE TECHNOLOGIES LLC Quant Increased +3.7K +7.6% $1.2K 0.0% 29
Engineers Gate Quant Reduced -1 -+0.0% $0 0.0% 17

Most significant buyers

By move score, not size.

  • CITADEL ADVISORS LLC New · +444.2K
  • TWO SIGMA INVESTMENTS, LP Increased · +1.13M
  • RENAISSANCE TECHNOLOGIES LLC Increased · +3.7K

Most significant sellers

By move score, not size.

  • MILLENNIUM MANAGEMENT LLC Sold Out · -3.56M
  • ADAR1 Capital Management Sold Out · -150.0K
  • EcoR1 Capital Reduced · -12.37M
  • Caption Management Sold Out · -64.1K
  • MARSHALL WACE, LLP Reduced · -507.1K

Hedge fund positions

Fund Tier Shares Previous Change Change % Portfolio wt. Action Score
MILLENNIUM MANAGEMENT LLC 2 0 3.6M -3.56M -100.0% 0.0% Sold Out 59
CITADEL ADVISORS LLC 1 444.2K 0 +444.2K — 0.0% New 58
ADAR1 Capital Management 3 0 150.0K -150.0K -100.0% 0.0% Sold Out 53
TWO SIGMA INVESTMENTS, LP 2 1.3M 187.8K +1.13M +602.3% 0.0% Increased 51
EcoR1 Capital 2 1.0M 13.4M -12.37M -92.5% 0.0% Reduced 50
Caption Management 3 0 64.1K -64.1K -100.0% 0.0% Sold Out 50
MARSHALL WACE, LLP 2 179.9K 687.0K -507.1K -73.8% 0.0% Reduced 44
RENAISSANCE TECHNOLOGIES LLC 1 52.1K 48.4K +3.7K +7.6% 0.0% Increased 29
Engineers Gate 4 24.0K 24.0K -1 -+0.0% 0.0% Reduced 17
Rubric Capital Management 1 15.3M 15.3M 0 +0.0% 0.0% Unchanged 23
Centiva Capital 4 25.0K 25.0K 0 +0.0% 0.0% Unchanged 12

Every fund above opens. Subscribers can see any manager's whole portfolio — every position, its weight, and what they bought, trimmed and exited last quarter.

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Hedge funds are identified from their 13F filings, which are due 45 days after quarter end and cover long U.S.-listed equity positions only. A fund's short book never appears, so a reduced position can mean a changed view or a changed hedge — the filing doesn't say which.