NASDAQ · SPROHealthcarePharmaceuticals

Spero Therapeutics, Inc. Common Stock (SPRO)

$1.07+2.88%
Close Nov 4, 2026 · split-adjusted
Nov 3, 2026$1.04▼ 56.30% in range
Nov 3, 2025Low $1.04 · High $2.98Nov 3, 2026
What changed · written from our data
As of Nov 4, 2026

Spero Therapeutics closed at $1.07 on Nov 4, up 2.88%, within 2.9% of its 52-week closing low. Volume of 210.3K shares was 0.56× its 20-day average (below normal).

Split-adjusted performance: -10.1% over one month, -57.7% over six months, -55.0% over one year.

Short interest was 840.5K shares at the Oct 15 settlement, up 5.8% from the prior report (2.0% of float, 1.5 days to cover).

Market cap$62.3M58.2M shares
Revenue · quarter$0.00−100.0% YoY
Diluted EPS$-0.16—
P/E · TTM8.4×P/S 1.3×
Net margin—
Dividend yieldNone
52-week range1.04 – 2.98−64.1% from high
Volume210.3K0.56× 20-day avg
Volatility · 60d59.0%Annualised
Short % of float2.0%1.5 days to cover
Net cash$50.7MCash $50.8M
Next earnings—Not scheduled
Split-adjusted performance
1W −8.5%1M −10.1%3M −15.7%6M −57.7%YTD −54.1%1Y −55.0%3Y +3.9%5Y −93.5%

Earnings reactions

History →

No reported quarters with price history yet.

Rank within Pharmaceuticals

Percentile among 420 companies (100 = best)

6-month momentum20
Revenue growth2
Net margin—
Value (low P/E)74
Size35

Industry medians: 6-month return −25.5%, revenue growth +6.2%, net margin −33.8%, P/E 16.1×.

Short interest

Details →
Shares short840.5K+5.8% vs prior
Days to cover1.5Settled Oct 15
% of float2.0%
Short vol. 10d39.3%of daily volume

Closest peers by size in Pharmaceuticals

CompanyPriceToday6MRev. growthNet marginP/EMkt cap
SPROSpero Therapeutics$1.07+2.88%−57.7%−100.0%—8.4$62.3M
QUCYQuantum Cyber N.V$0.7430+2.65%————$62.5MCompare
GOSSGossamer Bio$9.95+7.22%−64.5%−19.6%182.9%—$60.9MCompare
TELOTelomir Pharmaceuticals$0.8750−3.85%−34.7%———$64.5MCompare
XBITXBiotech$1.95−2.01%−23.5%———$59.5MCompare
VRCAVerrica Pharmaceuticals$3.46+5.02%−59.0%−53.8%−224.4%—$59.4MCompare
RNXTRenovoRx$1.31+1.55%+47.2%+115.4%−320.2%—$59.1MCompare
FBIOFortress Biotech$1.97+1.55%−22.7%+14.0%−13.2%0.6$65.7MCompare
RANIRani Therapeutics Holdings$0.5728+3.06%−40.3%—−432.7%—$66.1MCompare

Quick answers

What does Spero Therapeutics do?
Spero Therapeutics Inc is a clinical-stage biopharmaceutical firm. It focuses on identifying, developing, and commercializing novel treatments for MDR (Multi-drug-resistant) bacterial infections and rare diseases.
What is SPRO's market cap?
$62.31M, based on the Nov 4 close of $1.07.
What is SPRO's P/E ratio?
8.4× trailing-twelve-month earnings of $7.38M.
Does Spero Therapeutics pay a dividend?
No regular cash dividend has been paid in the last year.
How much of SPRO is sold short?
840.5K shares, 2.0% of float, as of Oct 15, 2026.
What sector is SPRO in?
Healthcare, in the Pharmaceuticals industry.

About Spero Therapeutics

Spero Therapeutics Inc is a clinical-stage biopharmaceutical firm. It focuses on identifying, developing, and commercializing novel treatments for MDR (Multi-drug-resistant) bacterial infections and rare diseases. The company's product candidate, tebipenem pivoxil hydrobromide or tebipenem HBr, is designed to be an oral carbapenem-class antibiotic for use in adults to treat MDR Gram-negative infections. It is also developing SPR720, a novel oral antibiotic designed for the treatment of a rare, orphan disease caused by pulmonary non-tuberculous mycobacterial infections, or NTM disease. It is also focused on SPR206, a next-generation polymyxin investigational product candidate being developed as an IV-administered medicine to treat MDR Gram-negative infections in the hospital.

HQ: Cambridge, MA25 employeesListed Nov 2, 2017sperotherapeutics.com

Sources: Massive / Polygon daily aggregates (split-adjusted) · SEC filings via Massive · FINRA settlements via Massive · Financial Modeling Prep. Figures are dated where shown; research is informational, not investment advice. Methodology