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Spero Therapeutics, Inc. (SPRO)

Spero Therapeutics, Inc. at a glance — key fundamentals, SEC filings, insider buying and selling, and earnings dates.

Spero Therapeutics, Inc. (SPRO) is a Biotechnology company based in US with a market capitalization of $163.3M. Revenue grew 24.3% year-over-year and free cash flow was negative at -$12.6M. This page tracks SPRO's SEC filings, insider buying and selling, earnings dates, and key fundamentals in one place.

US · 32 employees · IPO Nov 2, 2017

Valuation

Valuation & price

$2.79 · as of May 17, 2026 · -8.2% vs 52w high

19.2

P/E ratio

Latest-FY diluted EPS

2.77

P/B ratio

Market cap ÷ book equity

—

Dividend yield

Price — last 12 months

$3.04$2.44$1.84Jul 25Dec 25Jul 26Jul 7, 25$2.90Jul 9, 25$3.04Jul 11, 25$2.81Jul 15, 25$2.49Jul 17, 25$2.48Jul 21, 25$2.32Jul 23, 25$2.38Jul 25, 25$2.33Jul 29, 25$2.20Jul 31, 25$2.32Aug 4, 25$2.26Aug 6, 25$2.26Aug 11, 25$2.20Aug 13, 25$1.94Aug 15, 25$1.91Aug 19, 25$1.84Aug 21, 25$1.86Aug 25, 25$1.85Aug 27, 25$1.98Aug 29, 25$2.07Sep 3, 25$2.08Sep 5, 25$2.15Sep 9, 25$1.98Sep 11, 25$1.95Sep 16, 25$1.90Sep 18, 25$2.00Sep 22, 25$2.03Sep 24, 25$1.97Sep 26, 25$1.89Sep 30, 25$1.88Oct 2, 25$2.03Oct 6, 25$2.09Oct 8, 25$2.28Oct 10, 25$2.25Oct 14, 25$2.36Oct 16, 25$2.35Oct 21, 25$2.37Oct 23, 25$2.20Oct 27, 25$2.29Oct 29, 25$2.33Oct 31, 25$2.43Nov 4, 25$2.35Nov 6, 25$2.39Nov 10, 25$2.50Nov 12, 25$2.66Nov 14, 25$2.41Nov 18, 25$2.47Nov 20, 25$2.26Nov 25, 25$2.34Nov 28, 25$2.40Dec 2, 25$2.20Dec 4, 25$2.28Dec 8, 25$2.31Dec 10, 25$2.33Dec 12, 25$2.32Dec 16, 25$2.27Dec 18, 25$2.29Dec 22, 25$2.37Dec 24, 25$2.34Dec 29, 25$2.30Jan 2, 26$2.35Jan 6, 26$2.51Jan 8, 26$2.57Jan 12, 26$2.51Jan 14, 26$2.51Jan 16, 26$2.41Jan 21, 26$2.36Jan 23, 26$2.44Jan 27, 26$2.37Jan 29, 26$2.25Feb 2, 26$2.23Feb 4, 26$2.29Feb 9, 26$2.36Feb 11, 26$2.37Feb 13, 26$2.39Feb 18, 26$2.33Feb 20, 26$2.30Feb 24, 26$2.23Feb 26, 26$2.21Mar 2, 26$2.19Mar 4, 26$2.29Mar 6, 26$2.30Mar 10, 26$2.45Mar 12, 26$2.59Mar 17, 26$2.58Mar 19, 26$2.47Mar 23, 26$2.35Mar 25, 26$2.41Mar 27, 26$2.33Mar 31, 26$2.34Apr 2, 26$2.43Apr 7, 26$2.67Apr 9, 26$2.78Apr 13, 26$2.78Apr 15, 26$2.64Apr 17, 26$2.75Apr 22, 26$2.86Apr 24, 26$2.74Apr 28, 26$2.67Apr 30, 26$2.51May 4, 26$2.50May 6, 26$2.53May 8, 26$2.56May 12, 26$2.54May 14, 26$2.76May 18, 26$2.58May 20, 26$2.63May 22, 26$2.76May 28, 26$2.90Jun 1, 26$2.83Jun 3, 26$2.80Jun 5, 26$2.82Jun 9, 26$2.57Jun 11, 26$2.70Jun 15, 26$2.91Jun 17, 26$2.11Jun 22, 26$2.21Jun 24, 26$2.10Jun 26, 26$2.26Jul 2, 26$2.20
$1.8352-week range$3.04
Loading valuation history…

Fundamentals

Key fundamentals

$163.3M

Market cap

24.3%

Revenue growth (YoY)

100.0%

Gross margin

-$12.6M

Free cash flow (USD)

-$37.4M

Net debt

Net cash position

3.7%

Share dilution

1/5

Graham criteria passed

Defensive-investor screen

Healthcare

Sector

Trajectory

Long-term trends

Revenue by year

2016 → 2025

FY 2016$335.0KFY 2017$2.0MFY 2018$4.0MFY 2019$18.1MFY 2020$9.3MFY 2021$3.1MFY 2022$48.6MFY 2023$103.8MFY 2024$48.0MFY 2025$59.6M
$335K$59.6M

Free cash flow by year

2016 → 2025

FY 2016$-29.8MFY 2017$-39.1MFY 2018$-42.1MFY 2019$-50.3MFY 2020$-86.0MFY 2021$-128.7MFY 2022$-7.7MFY 2023$-33.0MFY 2024$-23.4MFY 2025$-12.6M
-$29.8M-$12.6M

Gross margin by year

2021 → 2025

FY 2021100.0%FY 2022100.0%FY 202350.4%FY 2024-101.7%FY 2025100.0%
100.0%100.0%

Value screen

Graham defensive-investor tests

Computing the scorecard — refreshing any stale inputs…

0

Insider buys · 90 days

1

Insider sells · 90 days

Earnings

Last report: 10-Q filed May 13, 2026

Next expected: not yet scheduled

On the tape

Recent SEC & insider activity

  • 8-K eventStockholder Meeting ResultsJun 25, 2026Filing
  • 8-K eventFDA ApprovalJun 22, 2026Filing
  • 8-K eventEarnings ReleaseMay 13, 2026Filing
  • Quarterly report10-Q FiledMay 13, 2026Filing
  • Insider sellInsider Sell $63KRajavelu Esther · See Remarks · $63.4KMay 6, 2026Filing

Questions

Frequently asked questions

What is Spero Therapeutics, Inc.'s market cap?

Spero Therapeutics, Inc. (SPRO) has a market capitalization of $163.3M.

What is SPRO's P/E ratio?

SPRO trades at a price-to-earnings ratio of 19.2, based on its latest fiscal-year diluted earnings per share and the most recent cached price.

What is SPRO's price-to-book (P/B) ratio?

SPRO trades at 2.77 times book value per share.

Are insiders buying SPRO stock?

SEC Form 4 filings show no open-market insider buys at Spero Therapeutics, Inc. in the last 90 days (1 sell).

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Timeline

Every filing, insider trade & earnings on a price-anchored timeline

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News

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Data: SEC EDGAR filings and cached fundamental data; prices and ratios use the most recent cached quote and statements (may lag by up to a day). Educational and research purposes only. Not investment advice.