SPRONasdaqPharmaceutical PreparationsFiscal year ends December 31
Spero Therapeutics, Inc.
Financials through Q2 FY2026, quarter ended Jun 30, 2026Last filing: 10-Q on Aug 12, 2026
$1.12+0.02 (+1.82%)
Close on Oct 19, 2026
- Market cap
- $64.92M
- P/E (TTM)
- 28.0
- Dividend yield
- –
Ownership
Institutional holdings as of Jun 30, 2026, from 13F filings
Held by institutions
36.9%
21M of 58M shares
Institutional holders
60
22 new, 12 sold out
Net institutional buying
0M
In Q2 2026
Insider trades, 12 months
0 buys · 9 sales
Net sold $552.04K
Shares held by institutions
Holders of more than 5%
Latest Schedule 13D (active) or 13G (passive) filed by each holder
| Holder | Shares | % of class | Filing | As of |
|---|---|---|---|---|
| Gsk PLC | 9,190,606 | 16.40% | 13D (active) amendment | Mar 27, 2025 |
Top institutional holders
13F holdings as of Jun 30, 2026
| Holder | Shares | % of SPRO | Value | Change | % of portfolio |
|---|---|---|---|---|---|
| GSK plc | 9,190,606 | 15.78% | $20.31M | – | 3.37% |
| Pfizer Inc | 2,362,348 | 4.06% | $5.34M | – | 3.13% |
| Vanguard Capital Management LLC | 2,036,226 | 3.50% | $4.50M | +236,346 | 0.00% |
| Renaissance Technologies LLC | 947,904 | 1.63% | $2.09M | −241,331 | 0.00% |
| Alphabet Inc. | 889,979 | 1.53% | $1.97M | – | 0.00% |
| Susquehanna International Group, Llp | 759,290 | 1.30% | $1.68M | +426,175 | 0.00% |
| BlackRock, Inc. | 594,404 | 1.02% | $1.31M | +161,202 | 0.00% |
| Geode Capital Management, LLC | 566,329 | 0.97% | $1.25M | +46,407 | 0.00% |
| Raymond James Financial Inc | 521,705 | 0.90% | $1.15M | New | 0.00% |
| Two Sigma Investments, LP | 382,814 | 0.66% | $846.02K | −502,817 | 0.00% |
| Arrowstreet Capital, Limited Partnership | 332,970 | 0.57% | $735.86K | New | 0.00% |
| Vanguard Fiduciary Trust Co | 287,648 | 0.49% | $635.70K | +23,533 | 0.00% |
| Gsa Capital Partners Llp | 285,906 | 0.49% | $632 | +7,602 | 0.04% |
| Dimensional Fund Advisors LP | 274,820 | 0.47% | $607.62K | +245,052 | 0.00% |
| Goldman Sachs Group Inc | 256,985 | 0.44% | $567.94K | New | 0.00% |
| State Street Corp | 214,751 | 0.37% | $474.60K | – | 0.00% |
| Jane Street Group, LLC | 158,097 | 0.27% | $349.39K | +51,752 | 0.00% |
| UBS Group AG | 139,680 | 0.24% | $308.69K | +136,671 | 0.00% |
| Bridgeway Capital Management, LLC | 114,800 | 0.20% | $253.71K | – | 0.00% |
| Northern Trust Corp | 108,274 | 0.19% | $239.29K | −12,710 | 0.00% |
Institutional buying and selling by quarter
Positions opened, added to, reduced and closed by 13F filers
| Quarter | Holders | Shares held | % of shares | New / added | Reduced / closed | Shares bought | Shares sold |
|---|---|---|---|---|---|---|---|
| Q2 2026 | 60 | 21M | 36.9% | 22 / 17 | 6 / 12 | 3M | 3M |
| Q1 2026 | 50 | 21M | 36.2% | 8 / 13 | 10 / 13 | 3M | 1M |
| Q4 2025 | 56 | 21M | 36.3% | 16 / 14 | 12 / 6 | 11M | 2M |
| Q3 2025 | 47 | 11M | 19.4% | 14 / 13 | 6 / 11 | 2M | 1M |
| Q2 2025 | 44 | 11M | 19.0% | 16 / 9 | 9 / 10 | 2M | 6M |
| Q1 2025 | 38 | 15M | 25.9% | 1 / 8 | 11 / 12 | 0M | 1M |
| Q4 2024 | 50 | 16M | 27.6% | 12 / 13 | 9 / 8 | 5M | 1M |
| Q3 2024 | 46 | 12M | 21.2% | 6 / 5 | 12 / 7 | 1M | 2M |
| Q2 2024 | 48 | 14M | 23.8% | 5 / 12 | 8 / 11 | 1M | 1M |
| Q1 2024 | 54 | 14M | 23.7% | 11 / 12 | 12 / 7 | 2M | 2M |
| Q4 2023 | 50 | 14M | 23.8% | 6 / 11 | 10 / 8 | 2M | 0M |
| Q3 2023 | 54 | 14M | 24.4% | 5 / 12 | 14 / 7 | 1M | 1M |
Top mutual fund and ETF holders
Latest monthly portfolio reports (Form N-PORT)
| Fund | Shares | % of SPRO | Value | % of fund | As of |
|---|---|---|---|---|---|
| Vanguard Total Stock Market Index Fund | 1,395,976 | 2.40% | $3.09M | 0.00% | Jun 30, 2026 |
| Vanguard Extended Market Index Fund | 593,254 | 1.02% | $1.31M | 0.00% | Jun 30, 2026 |
| Fidelity Extended Market Index Fund | 224,070 | 0.38% | $634.12K | 0.00% | May 31, 2026 |
| iShares Micro-Cap ETF | 151,203 | 0.26% | $334.16K | 0.02% | Jun 30, 2026 |
| Fidelity Total Market Index Fund | 107,797 | 0.19% | $305.07K | 0.00% | May 31, 2026 |
| Fidelity Series Total Market Index Fund | 67,356 | 0.12% | $190.62K | 0.00% | May 31, 2026 |
| Dimensional U.S. Small Cap ETF | 65,997 | 0.11% | $77.22K | 0.00% | Jul 31, 2026 |
| Ultra-Small Company Market Fund | 64,800 | 0.11% | $143.21K | 0.10% | Jun 30, 2026 |
| Acuitas US Microcap Fund | 56,457 | 0.10% | $124.77K | 0.11% | Jun 30, 2026 |
| Omni Small-Cap Value Fund | 50,000 | 0.09% | $110.50K | 0.01% | Jun 30, 2026 |
| U.S. Micro Cap Portfolio | 46,660 | 0.08% | $54.59K | 0.00% | Jul 31, 2026 |
| Fidelity Nasdaq Composite Index Fund | 36,745 | 0.06% | $103.99K | 0.00% | May 31, 2026 |
| Invesco NASDAQ Future Gen 200 ETF | 35,591 | 0.06% | $100.72K | 0.53% | May 31, 2026 |
| Schwab Total Stock Market Index Fund | 28,565 | 0.05% | $33.42K | 0.00% | Jul 31, 2026 |
| Invesco RAFI US 1500 Small-Mid ETF | 26,957 | 0.05% | $31.54K | 0.00% | Jul 31, 2026 |
Officers, directors and major owners
People who filed Forms 3, 4 or 5 in the last two years
| Name | Role | Shares owned | % of shares | Latest filing |
|---|---|---|---|---|
| Debra Zack | Chief Medical Officer | 162,311 | 0.28% | Aug 6, 2026 |
| Esther Rajavelu | See Remarks | 986,851 | 1.69% | May 6, 2026 |
| Timothy Keutzer | Chief Operating Officer | 742,506 | 1.28% | Feb 9, 2026 |
| Sath Shukla | CEO & President | 1,886,077 | 3.24% | Feb 5, 2025 |
| Kathleen Tregoning | Director | 85,000 | 0.15% | Jun 25, 2026 |
| Cynthia Smith | Director | 85,000 | 0.15% | Jun 25, 2026 |
| John C. Pottage Jr | Director | 85,000 | 0.15% | Jun 25, 2026 |
| Milind Deshpande | Director | 101,454 | 0.17% | Jun 25, 2026 |
| Frank E. Thomas | Director | 85,000 | 0.15% | Jun 25, 2026 |
| Scott Thomas Jackson | Director | 85,000 | 0.15% | Jun 25, 2026 |
| Patrick V.J.J. Vink | Director | 85,000 | 0.15% | Jun 25, 2026 |
| Ankit Mahadevia | Director | 769,111 | 1.32% | Sep 3, 2025 |
Insider trades
Common stock transactions reported on Form 4, newest first
| Insider | Date | Transaction | Shares | Price | Value | Shares after |
|---|---|---|---|---|---|---|
| Debra Zack Chief Medical Officer | Aug 3, 2026 | Award | +162,311 | – | – | 162,311 |
| Frank E. Thomas Director | Jun 23, 2026 | Award | +10,000 | – | – | 85,000 |
| Patrick V.J.J. Vink Director | Jun 23, 2026 | Award | +10,000 | – | – | 85,000 |
| Milind Deshpande Director | Jun 23, 2026 | Award | +10,000 | – | – | 101,454 |
| Kathleen Tregoning Director | Jun 23, 2026 | Award | +10,000 | – | – | 85,000 |
| Cynthia Smith Director | Jun 23, 2026 | Award | +10,000 | – | – | 85,000 |
| Scott Thomas Jackson Director | Jun 23, 2026 | Award | +10,000 | – | – | 85,000 |
| John C. Pottage Jr Director | Jun 23, 2026 | Award | +10,000 | – | – | 85,000 |
| Esther Rajavelu See Remarks | May 4, 2026 | Sale | −25,240 | $2.51 | $63.35K | 986,851 |
| Timothy Keutzer Chief Operating Officer | Feb 6, 2026 | Sale | −18,652 | $2.36 | $44.02K | 742,506 |
| Esther Rajavelu See Remarks | Feb 6, 2026 | Sale | −50,816 | $2.36 | $119.93K | 1,012,091 |
| Esther Rajavelu See Remarks | Feb 6, 2026 | Sale | −37,101 | $2.36 | $87.56K | 1,062,907 |
| Timothy Keutzer Chief Operating Officer | Feb 4, 2026 | Sale | −3,471 | $2.24 | $7.78K | 761,158 |
| Timothy Keutzer Chief Operating Officer | Feb 3, 2026 | Sale | −24,224 | $2.14 | $51.84K | 764,629 |
| Timothy Keutzer Chief Operating Officer | Feb 2, 2026 | Award | +68,000 | – | – | 807,744 |
| Timothy Keutzer Chief Operating Officer | Feb 2, 2026 | Sale | −18,891 | $2.20 | $41.56K | 788,853 |
| Esther Rajavelu See Remarks | Feb 2, 2026 | Award | +249,000 | – | – | 1,118,450 |
| Esther Rajavelu See Remarks | Feb 2, 2026 | Sale | −18,442 | $2.20 | $40.57K | 1,100,008 |
| Esther Rajavelu See Remarks | Nov 7, 2025 | Sale | −40,270 | $2.37 | $95.44K | 869,450 |
| Timothy Keutzer Chief Operating Officer | Aug 28, 2025 | Sale | −1,695 | $1.97 | $3.34K | 739,744 |
| Ankit Mahadevia Director | Aug 28, 2025 | Sale | −6,572 | $1.97 | $12.95K | 703,294 |
| John C. Pottage Jr Director | Jun 12, 2025 | Award | +20,000 | – | – | 75,000 |
| Kathleen Tregoning Director | Jun 12, 2025 | Award | +20,000 | – | – | 75,000 |
| Cynthia Smith Director | Jun 12, 2025 | Award | +20,000 | – | – | 75,000 |
| Scott Thomas Jackson Director | Jun 12, 2025 | Award | +20,000 | – | – | 75,000 |
| Ankit Mahadevia Director | Jun 12, 2025 | Award | +20,000 | – | – | 709,866 |
| Frank E. Thomas Director | Jun 12, 2025 | Award | +20,000 | – | – | 75,000 |
| Milind Deshpande Director | Jun 12, 2025 | Award | +20,000 | – | – | 91,454 |
| Patrick V.J.J. Vink Director | Jun 12, 2025 | Award | +20,000 | – | – | 75,000 |
| Esther Rajavelu See Remarks | May 2, 2025 | Award | +185,000 | – | – | 909,720 |
| Sath Shukla CEO & President | Feb 5, 2025 | Sale | −6,139 | $0.78 | $4.79K | 1,886,077 |
| Sath Shukla CEO & President | Feb 5, 2025 | Sale | −42,786 | $0.78 | $33.37K | 1,843,291 |
| Sath Shukla CEO & President | Feb 5, 2025 | Sale | −106,408 | $0.78 | $83.00K | 1,736,883 |
| Esther Rajavelu CFO & CBO | Feb 5, 2025 | Sale | −20,689 | $0.78 | $16.14K | 724,720 |
| Ankit Mahadevia Director | Feb 5, 2025 | Sale | −55,260 | $0.78 | $43.10K | 689,866 |
| Ankit Mahadevia Director | Feb 5, 2025 | Sale | −13,959 | $0.78 | $10.89K | 745,126 |
| Timothy Keutzer Chief Operating Officer | Feb 5, 2025 | Sale | −3,974 | $0.78 | $3.10K | 794,002 |
| Timothy Keutzer Chief Operating Officer | Feb 5, 2025 | Sale | −27,643 | $0.78 | $21.56K | 766,359 |
| Timothy Keutzer Chief Operating Officer | Feb 5, 2025 | Sale | −24,920 | $0.78 | $19.44K | 741,439 |
| Sath Shukla CEO & President | Feb 3, 2025 | Award | +751,407 | – | – | 1,892,216 |
| Esther Rajavelu CFO & CBO | Feb 3, 2025 | Award | +266,139 | – | – | 645,409 |
| Esther Rajavelu CFO & CBO | Feb 3, 2025 | Award | +100,000 | – | – | 745,409 |
| Timothy Keutzer Chief Operating Officer | Feb 3, 2025 | Award | +266,139 | – | – | 797,976 |
| Esther Rajavelu CFO & CBO | Nov 8, 2024 | Sale | −17,245 | $1.30 | $22.42K | 379,270 |
| Esther Rajavelu CFO & CBO | Nov 7, 2024 | Sale | −23,351 | $1.31 | $30.59K | 396,515 |
| Ankit Mahadevia Director | Aug 27, 2024 | Sale | −5,912 | $1.35 | $7.98K | 759,085 |
| Timothy Keutzer Chief Operating Officer | Aug 27, 2024 | Sale | −2,213 | $1.35 | $2.99K | 531,837 |
| Sath Shukla CEO & President | Aug 27, 2024 | Sale | −2,757 | $1.35 | $3.72K | 1,140,809 |
| Sath Shukla CEO and President | Aug 5, 2024 | Sale | −17,641 | $1.31 | $23.11K | 1,143,566 |
| Sath Shukla CEO and President | Aug 2, 2024 | Sale | −14,800 | $1.32 | $19.54K | 1,161,207 |
| Kathleen Tregoning Director | May 29, 2024 | Award | +20,000 | – | – | 55,000 |
| Cynthia Smith Director | May 29, 2024 | Award | +20,000 | – | – | 55,000 |
| Scott Thomas Jackson Director | May 29, 2024 | Award | +20,000 | – | – | 55,000 |
| John C. Pottage Jr Director | May 29, 2024 | Award | +20,000 | – | – | 55,000 |
| Frank E. Thomas Director | May 29, 2024 | Award | +20,000 | – | – | 55,000 |
| Ankit Mahadevia Director | May 29, 2024 | Award | +20,000 | – | – | 764,997 |
| Milind Deshpande Director | May 29, 2024 | Award | +20,000 | – | – | 71,454 |
| Patrick V.J.J. Vink Director | May 29, 2024 | Award | +20,000 | – | – | 55,000 |
| Sath Shukla CEO and President, Director | Feb 5, 2024 | Sale(10b5-1 plan) | −45,093 | $1.45 | $65.38K | 1,176,007 |
| Sath Shukla CEO and President, Director | Feb 2, 2024 | Sale(10b5-1 plan) | −30,901 | $1.37 | $42.33K | 1,221,100 |
Awards, option exercises, tax withholding and gifts are shown alongside open-market buys and sales. Each name links to the filing on SEC EDGAR.
Planned insider sales
Notices of proposed sale filed on Form 144 before shares are sold
| Seller | Filed | Shares | Market value | Planned sale | Acquired through |
|---|---|---|---|---|---|
| Shukla Satyavrat Officer, Director | Feb 5, 2024 | 45,093 | $65.47K | Feb 5, 2024 | Restricted Stock |
| Shukla Satyavrat Officer | Aug 29, 2023 | 4,163 | $5.41K | Aug 29, 2023 | Restricted Stock |