Security key
84833T103
Spero Therapeutics, Inc. - Common Stock, par value $0.001 per share (SPRO)
CUSIP: 84833T103
Q4 2025 13F Holders as of 31 Dec 2025
- Security type / class
- Equity / Common Stock, par value $0.001 per share
- Total 13F shares
- 21,119,398
- Total 13F value
- $49,213,763
- Share change
- +658,135
- SEC-reported price per share
- $2.33
- Number of holders
- 56
- Value change
- +$1,640,743
- Number of buys
- 29
- Number of sells
- 18
- Shares outstanding
- 55,705,828
Holder snapshot
6 signals
Security identity
Names, identifiers, and filing context for this profile.
1 source field
Report period
Q4 2025
Institutions
56
Top holders
10
SPRO full security history
Ownership snapshot
Full 13F holder table
Newer quarter: Q1 2026
Previous quarter: Q3 2025
Spero Therapeutics, Inc. SEC filings
Spero Therapeutics, Inc. company facts
Broader feeds
Reporting periods
Holder history for CUSIP 84833T103
Recent filing periods:
Ownership snapshot
Top reported holders of SPRO - Spero Therapeutics, Inc. - Common Stock, par value $0.001 per share (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
GSK plc
Disclosed value leader
GSK plc
Comparable rows
15/15
Latest evidence
30 Sep 2025
3/4/5
13D/G
13F
Lead comparable stake: 16%
13D/G row: GSK plc
Showing 1-6 of 15 holder rows.
Quick read
GSK plc leads the comparable SEC ownership view at 16%.
15 of 15 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens GSK plc's linked filing trail.
Comparable ownership
Top 5
GSK plc
16%
Anson Funds Management LP
2.9%
Ankit Mahadevia
1.3%
PFIZER INC
4.2%
VANGUARD GROUP INC
3.6%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-6 of 15 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| GSK plc |
3/4/5
13D/G
10%+ Owner
|
16%
from 13D/G
|
$11,672,070
9,190,606 shares
|
— | 07 Nov 2022 |
| Anson Funds Management LP |
13D/G
13F
Company
|
2.9%
|
$4,587,932
1,615,469 shares
|
$0 | 30 Jun 2025 |
| Ankit Mahadevia |
3/4/5
Director
|
1.3%
|
$1,385,489
703,294 shares
|
-$12,947 | 28 Aug 2025 |
| PFIZER INC |
13F
Company
|
4.2%
|
$4,441,214
2,362,348 shares
|
— | 30 Sep 2025 |
| VANGUARD GROUP INC |
13F
Company
|
3.6%
|
$3,740,928
1,989,855 shares
|
— | 30 Sep 2025 |
| RENAISSANCE TECHNOLOGIES LLC |
13F
Company
|
2.6%
|
$2,731,198
1,452,765 shares
|
— | 30 Sep 2025 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
13F holder rows
Institutional holders as of Q4 2025
Investor-level positions for this CUSIP, loaded as an interactive table.
Institutions
56
Shares
21,119,398
Rows available
56
| Investor | Option | Weight % | Change % | SEC-reported value | * Price | Shares | Share Change | Activity | Report Period |
|---|
* SEC-reported price is the security price as of the portfolio date and can indicate the last known price at which the security was still held. The marker flags a reported price that did not pass the local price check.
Compare Q4 2025 vs Q3 2025 Across Filers
Q3 2025 holders
47
Q4 2025 holders
56
Holder diff
9
| Investor | Q3 2025 Shares | Q4 2025 Shares | Share Diff | Share Chg % | Q3 2025 value | Q4 2025 value | Value change | Value Chg % |
|---|
Trend: ostatnie 8 kwartałów (+ wybrane okresy porównania).
Quarterly Holders Trend
Quarterly Value Trend
Quarterly Shares Trend