Security key
84833T103
Spero Therapeutics, Inc. - Common Stock, par value $0.001 per share (SPRO)
CUSIP: 84833T103
Q3 2026 13F Holders as of 30 Sep 2026
- Security type / class
- Equity / Common Stock, par value $0.001 per share
- Total 13F shares
- 65,883
- Total 13F value
- $78,946
- Share change
- -51,729
- SEC-reported price per share
- $1.21
- Number of holders
- 5
- Value change
- -$98,435
- Number of buys
- 2
- Number of sells
- 3
- Shares outstanding
- 55,705,828
Holder snapshot
6 signals
Security identity
Names, identifiers, and filing context for this profile.
1 source field
Report period
Q3 2026
Institutions
5
Top holders
5
SPRO full security history
Ownership snapshot
Full 13F holder table
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
2/15
Latest evidence
30 Jun 2026
13F
13D/G
3/4/5
Lead comparable stake: 16%
13 rows are not safely comparable across share classes.
13D/G row: GSK plc
Showing 1-6 of 15 holder rows.
Quick read
GSK plc leads the comparable SEC ownership view at 16%.
2 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 2
GSK plc
16%
Anson Funds Management LP
2.9%
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 |
13F
13D/G
3/4/5
Company · 10%+ Owner
|
16%
Reported 13D/G
· 27 Mar 2025
|
$20,311,239
9,190,606 shares
|
— | 30 Jun 2026 |
| Anson Funds Management LP |
13D/G
|
2.9%
Reported 13D/G
· 30 Jun 2025
|
$4,587,932
1,615,469 shares
|
$0 | 30 Jun 2025 |
| Aquilo Capital Management, LLC |
3/4/5
10%+ Owner
|
—
denominator unverified
|
$4,342,682
3,419,435 shares
|
— | 22 Sep 2022 |
| PFIZER INC |
13F
Company
|
—
denominator unverified
|
$5,338,906
2,362,348 shares
|
— | 30 Jun 2026 |
| VANGUARD CAPITAL MANAGEMENT LLC |
13F
Company
|
—
denominator unverified
|
$4,500,059
2,036,226 shares
|
— | 30 Jun 2026 |
| Esther Rajavelu |
3/4/5
Chief Executive Officer, Chief Financial Officer and Chief Business Officer
|
—
mixed-class rows
|
$2,476,996
1,484,851 shares
mixed-class rows
|
-$406,849 | 04 May 2026 |
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 Q3 2026
Investor-level positions for this CUSIP, loaded as an interactive table.
Institutions
5
Shares
65,883
Rows available
5
| 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 Q3 2026 vs Q2 2026 Across Filers
Q2 2026 holders
59
Q3 2026 holders
5
Holder diff
-54
| Investor | Q2 2026 Shares | Q3 2026 Shares | Share Diff | Share Chg % | Q2 2026 value | Q3 2026 value | Value change | Value Chg % |
|---|
Trend: ostatnie 8 kwartałów (+ wybrane okresy porównania).
Quarterly Holders Trend
Quarterly Value Trend
Quarterly Shares Trend