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Spero Therapeutics
SPRO

56 hedge funds and large institutions have $49.2M invested in Spero Therapeutics in 2025 Q4 according to their latest regulatory filings, with 16 funds opening new positions, 14 increasing their positions, 12 reducing their positions, and 6 closing their positions.

New
Increased
Maintained
Reduced
Closed

167% more first-time investments, than exits

New positions opened: 16 | Existing positions closed: 6

131% more capital invested

Capital invested by funds: $21.3M → $49.2M (+$27.9M)

19% more funds holding

Funds holding: 47 → 56 (+9)

17.39% more ownership

Funds ownership: 20.1% → 37.49% (+17%)

17% more repeat investments, than reductions

Existing positions increased: 14 | Existing positions reduced: 12

14% less call options, than puts

Call options by funds: $263K | Put options by funds: $306K

Holders
56
Holders Change
+9
Holders Change %
+19.15%
% of All Funds
0.68%
Holding in Top 10
1
Holding in Top 10 Change
+1
Holding in Top 10 Change %
% of All Funds
0.01%
New
16
Increased
14
Reduced
12
Closed
6
Calls
$263K
Puts
$306K
Net Calls
-$43K
Net Calls Change
+$117K

Top Buyers

1
Citadel Advisors
Citadel Advisors
Florida
+$924K
2
Two Sigma Investments
Two Sigma Investments
New York
+$750K
3
Susquehanna International Group
Susquehanna International Group
Pennsylvania
+$682K
4
Two Sigma Advisers
Two Sigma Advisers
New York
+$503K
5
SEI Investments
SEI Investments
Pennsylvania
+$307K

Top Sellers

1
AFM
Anson Funds Management
Texas
-$2.27M
2
Renaissance Technologies
Renaissance Technologies
New York
-$402K
3
Arrowstreet Capital
Arrowstreet Capital
Massachusetts
-$283K
4
EI
EAM Investors
California
-$149K
5
Morgan Stanley
Morgan Stanley
New York
-$100K
Name Holding Trade Value Shares
Change 		Change in
Stake
GP
1
GSK plc
$21.4M +$21.3M +9,190,606 New
P
2
Pfizer
New York
$5.5M – – –
Vanguard Group
3
Vanguard Group
Pennsylvania
$4.85M +$217K +93,607 +5%
Renaissance Technologies
4
Renaissance Technologies
New York
$2.98M -$402K -173,243 -12%
AI
5
Alphabet Inc
California
$2.07M – – –
AFM
6
Anson Funds Management
Texas
$1.46M -$2.27M -978,507 -61%
Geode Capital Management
7
Geode Capital Management
Massachusetts
$1.23M +$3.99K +1,718 +0.3%
BlackRock
8
BlackRock
New York
$1.01M -$2.67K -1,152 -0.3%
Citadel Advisors
9
Citadel Advisors
Florida
$927K +$924K +397,864 New
Two Sigma Investments
10
Two Sigma Investments
New York
$868K +$750K +323,171 +654%
Susquehanna International Group
11
Susquehanna International Group
Pennsylvania
$684K +$682K +293,700 New
EI
12
EAM Investors
California
$508K -$149K -64,361 -23%
Two Sigma Advisers
13
Two Sigma Advisers
New York
$505K +$503K +216,600 New
State Street
14
State Street
Massachusetts
$490K +$44.6K +19,200 +10%
ICM
15
Ionic Capital Management
New York
$457K -$29.7K -12,786 -6%
GCP
16
GSA Capital Partners
United Kingdom
$417K +$167K +72,036 +67%
IFO
17
Intrepid Family Office
Florida
$384K +$128K +55,000 +50%
Jane Street
18
Jane Street
New York
$369K +$268K +115,356 +268%
SEI Investments
19
SEI Investments
Pennsylvania
$308K +$307K +132,010 New
OAC
20
OMERS Administration Corp
Ontario, Canada
$306K +$304K +131,127 New
Northern Trust
21
Northern Trust
Illinois
$282K -$20.1K -8,659 -7%
Squarepoint
22
Squarepoint
New York
$278K +$277K +119,434 New
UBS Group
23
UBS Group
Switzerland
$271K +$207K +89,346 +330%
BCM
24
Bridgeway Capital Management
Texas
$267K – – –
ACM
25
ADAR1 Capital Management
Texas
$265K -$3.95K -1,700 -1%
1
2 3

SPRO Hedge Fund Activity: Q4 2025 in Review

56 of the 8,223 institutional investors tracked by Wall St. Rank reported a position in Spero Therapeutics (SPRO) for Q4 2025, worth a combined $49.2M — up 131% from $21.3M a quarter earlier.

Buyers outnumbered sellers: 16 funds opened new SPRO positions and 6 closed out — a net gain of 10 holders — while 14 added to existing stakes and 12 trimmed.

The largest buyer was Citadel Advisors, opening a new position worth an estimated $924K. The largest seller was Anson Funds Management, cutting an estimated $2.27M.

  • 56 institutional investors held Spero Therapeutics (SPRO) as of Q4 2025, up from 47 in Q3 2025.
  • Funds reported $49.2M of Spero Therapeutics stock for Q4 2025, up 131% quarter-over-quarter.
  • 16 funds opened new Spero Therapeutics positions in Q4 2025 and 6 closed out, a net change of +10 holders.
  • The largest Spero Therapeutics buyer in Q4 2025 was Citadel Advisors, an estimated $924K added.
  • The largest Spero Therapeutics seller in Q4 2025 was Anson Funds Management, an estimated $2.27M sold.

Based on aggregated 13F filings for Q4 2025.