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28 /100
MEDIUM RISK
Score updated Oct 13, 2026

SPRO — Spero Therapeutics, Inc. Dilution Risk Tracker

Track SPRO dilution risk with DilutionWatch's stock tracker. DilutionScore™ measures dilution risk across 5 factors — lower scores indicate higher risk of share dilution.

⚠️ Not financial advice. Do your own research before making any investment decisions.

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As of October 13, 2026, Spero Therapeutics, Inc. (SPRO) has a DilutionWatch DilutionScore of 28/100, rated MEDIUM dilution risk. Spero Therapeutics, Inc. has a market capitalization of $68.72M, 58.23M shares outstanding, 51 institutional holders tracked.

This page includes automatically generated factual summaries from DilutionWatch data. It is not financial advice, not investment research, and not a recommendation. Do your own research. Read the full disclaimer and terms of service.

Score Breakdown

📋 Offering Ability
40
💰Cash Runway—
📊 Float Risk
22
⚠️ Warrant Exposure
40
🔄 Convertible Debt
40

Dilution Forecast

☀️
Clear
No significant dilution signals
model est. 0%
No significant dilution signals detected for SPRO.
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Market Data

Market Cap$68.72M
Shares Outstanding58.23M
Float46.52M
Cash$50.77M
Debt$2.47M
Short InterestN/A

Source-Backed Evidence Depth

This public preview uses stored DilutionWatch fields and linked SEC/market records only. Missing values are not estimated.

FieldCurrent ValueBasis
DilutionScore28/100DilutionWatch score record
Shares Outstanding58.23MVerified float table or market cache
Public Float46.52MVerified float table or market cache
Market Cap$68.72MMarket data cache
Cash RunwayNot applicable / unavailableDilutionWatch score inputs
Shelf CapacityNone in current score inputsSEC-derived dilution fields
ATM CapacityNone in current score inputsSEC-derived dilution fields
Outstanding WarrantsNone in current score inputsSEC-derived dilution fields

Recent source-backed SEC insight records available on this page: 1.

Recent SEC source mix: XBRL 1.

The page does not infer future share issuance, financing probability, cash needs, management intent, or price impact when source fields are absent.

Institutional Holdings

QoQ: ↑ 8.0% shares (2026Q1 vs prior)
51 institutional holders · 23.08M shares
#1 GSK plc 9.19M shares
#2 VANGUARD CAPITAL MANAGEMENT LLC 3.60M shares
#3 Pfizer Inc 2.36M shares
+ 17 more holders Sign up free to view →

Institutional holder totals are aggregated from ownership filings and may use a different share basis or reporting date than public float. They are not a reconciliation against tradeable float.

Short Interest

Short Interest794.5K
Days to Cover1.0
% of Float1.7%
FINRA data as of Sep 30, 2026

Recent SEC Activity

xbrl XBRL CONVERTIBLE 2024-03-13
Full SEC filing analysis available with free account →

Recent News

No recent news available for this ticker.

Factual SPRO Dilution Snapshot

Spero Therapeutics, Inc. (SPRO) has a DilutionScore of 28/100, rated Medium dilution risk. Score date: October 13, 2026.

This automatically generated snapshot is assembled from stored DilutionWatch data fields and may contain data-source errors or omissions. It is not financial advice, not investment research, and not a recommendation. Do your own research and review the full disclaimer and terms of service.

DilutionScore History — Last 90 Days

SPRO's DilutionScore is currently 28/100 (Medium risk), with 3 score changes tracked over 89 days. The score deteriorated from 29/100 (Medium risk).

Period Score Risk Level Duration
Oct 13, 202628/100MEDIUM1 day
Aug 30 – Oct 12, 202629/100MEDIUM44 days
Aug 22 – Aug 29, 202626/100MEDIUM8 days
Jul 16 – Aug 21, 202624/100LOW36 days

Score recalculated daily from SEC filings and market data. Sign up free for real-time score change alerts.

Share Dilution History

SPRO shares outstanding have increased 0.0% from 57.89M (Mar 2026) to 57.90M (May 2026). Each increase represents potential dilution to existing shareholders.

Date Shares Outstanding Public Float Change
May 30, 202657.90M46.52M▼ 1.73%
May 16, 202657.90M47.34M▲ 0.02%
Apr 01, 202657.89M47.33M▲ 0.62%
Mar 30, 202657.89M47.04M▲ 2.76%

Share counts sourced from verified regulatory filings. Increases indicate dilution events.

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