SPRO · CIK 0001701108
Spero Therapeutics, Inc.
What Spero Therapeutics, Inc. owns has not been researched yet. This page is its ownership register, who holds it, and the absence of holdings below means nobody has looked rather than that there is nothing to find.
Spero Therapeutics, Inc. - Profile
- Industry
- Pharmaceutical PreparationsSIC 2834
- Listed on
- Nasdaq
- Employees
- 25stated 2025
- Incorporated in
- Delaware
- Financial year ends
- 31 December
Source
Address, industry classification, listing and incorporation come from Spero Therapeutics, Inc.'s own SEC filer record, so the industry is the SEC's dry classification rather than a marketing label. The headcount is the figure the sources below state for 2025. The description was written for this site in August 2026 from Spero Therapeutics, Inc. Form 10-Q for the quarter ended 30 June 2026, Spero Therapeutics, Inc. Form 8-K dated 14 July 2026 (Innovent licence and royalty financing), Spero Therapeutics, Inc. Form 8-K dated 12 August 2026, Exhibit 99.1 (second quarter 2026 results) and Spero Therapeutics, Inc. Form 10-K for fiscal year 2025, not taken from any single article.
Share price
SPRO
Description
Spero Therapeutics, Inc. is a clinical-stage biopharmaceutical company in Cambridge, Massachusetts that has pivoted out of anti-infectives into immunology. It discontinued SPR206 and SPR720, cut headcount in an October 2024 restructuring, and ended its BARDA contract by mutual agreement on 6 July 2026. Tebipenem pivoxil, which Spero developed as tebipenem HBr, is licensed to GSK: the Phase 3 PIVOT-PO trial stopped early for efficacy in May 2025 and the FDA approved the drug as Utebzi for complicated urinary tract infections on 17 June 2026, leaving Spero eligible for up to $101.0 million of launch milestones, $225.0 million of sales milestones and royalties. On 8 July 2026 Spero sold most of those GSK proceeds to HealthCare Royalty affiliates for $105.0 million and licensed SP001, Innovent Biologics' Phase 2 ready anti-CD40L antibody, for $35.0 million upfront plus up to $1.05 billion in milestones. SP001 is now the lead programme, bound for a Phase 2 trial in IgG4-related disease in the second quarter of 2027. Net loss was $9.6 million in the second quarter of 2026 and $16.8 million in the first half, after net income of $8.6 million in 2025 on GSK milestones. Cash was $50.8 million at 30 June 2026, which with the financing proceeds is guided to fund operations into the second half of 2029. Spero had 25 employees at 31 December 2025.
Who owns Spero Therapeutics, Inc..
Nothing recorded on this side. That is a sourced finding rather than a gap where the research notes say so: see the notes below.
Select a row or a slice for its provenance: the filing it came from, when it was measured, and the arithmetic behind it if it was modelled.
The full register, from 13F filings
The Register tab above is hand research: a dozen holders, each traced to the filing it came from. This asks the same question of the whole market for the quarter ended 31-mar-2026, where 48 managers reported a position. Broad where the research is deep, and shallow in the ways a 13F always is.
48 managers reported a position, together holding 21.1m shares, or 36.4% of the company. The 40 largest are listed. Percentages are of the 57.9m shares outstanding at 1 May 2026, the count in force when this quarter was measured rather than the count today.
Built from 13F filings, which report US listed, long, US custodied positions only. A register from this source is a floor rather than a level: a holder's true position can be far larger, as BlackRock's ASML stake shows at 1.28m shares in a 13F against 26.3m in its 13G/A. Holdings held through derivatives, outside US custody, or below a manager's reporting obligation do not appear. Where a holder is marked as a family, its total sums several separate filing entities and describes something no single filing describes; the constituent entities and their share counts are listed so the total can be checked. That roll-up can legitimately exceed the family's own Schedule 13G, because a 13G is filed by one legal entity: Vanguard reports Alphabet through ten advisory entities, and The Vanguard Group Inc itself reported zero after its January 2026 disaggregation.
What a reader needs to know to read these numbers
- Added 27 Aug 2026 by scripts/promote_discovered.py. This company reached the site because a covered investor holds it, not because an index listed it: it was a position in a portfolio here with no page of its own. The match was proved by requiring the register built for this CIK to contain the same CUSIP the portfolio held.
- Discovered at CUSIP 84833T103, held by alphabet, blackrock, citigroup, fidelity-fmr, geode, goldman-sachs, invesco, jpmorgan, morgan-stanley, northern-trust, pfizer, prudential-financial, raymond-james, state-street, us-bancorp, vanguard, wells-fargo.
- Holdings are NOT researched. The empty holdings list means nobody has looked at what this company owns, not that it owns nothing, and the page says so.
- Shares outstanding and market cap are null rather than guessed. Neither was captured on the dated sweep that carries every other company here.
Looked for, not found
Recorded rather than filled in. Each of these is a place where a number could have been invented and was not.
- Shares outstanding.
- Market capitalisation.