Spero Therapeutics, Inc. (SPRO)
Nasdaq: SPRO · Pharmaceutical Preparations · Cambridge, MA · filing with the SEC since 2017
Filings
288 filings since 2017 beside 233 insider forms · Non-accelerated filer and smaller reporting company · read from EDGAR on Nov 13, 2026Due nextNon-accelerated filer and smaller reporting company
10-K
Annual report for the fiscal year ending Dec 31, 2026Non-accelerated filers and smaller reporting companies have 90 days after the fiscal year ends.
by Mar 31, 2027
10-Q
Quarterly report for the quarter ending Mar 31, 2027Non-accelerated filers and smaller reporting companies have 45 days after the quarter ends; quarter ends are taken to the month end.
by May 15, 2027
A deadline is the latest date the SEC's rules allow for its filer category. It is not a forecast of the day the company files. Last time, the results release (8-K item 2.02) came 43 days after the quarter ended. The proxy statement was last filed Apr 27, 2026.
Filings a yearinsider forms included
4267706453483640
2026 counts to Nov 13, 2026.
Officer or director change (8-K item 5.02): 9 times in the last 36 months, the newest Nov 10, 2026.Listing warning from its exchange (8-K item 3.01): 1 time in the last 36 months, the newest Feb 28, 2025.SEC letters: 2 in the last 36 months, the newest Mar 20, 2024.
Insider forms (3, 4, 5 and 144) are counted each year but not listed here; the people and their trades are on the Ownership tab.
FiledFormWhat it is, in plain wordsPeriodAsk
Jul 14, 2026
8-K items 1.01, 2.03, 7.01, 8.01, 9.01
Major agreement signed; New debt or obligation taken on; Investor disclosure (Regulation FD); Other event · Current report
Jul 8, 2026
Jun 25, 2026
8-K items 5.02, 5.03, 5.07, 9.01
Officer or director change; Charter, bylaw or fiscal-year change; Shareholder vote · Current report
Jun 23, 2026
Jun 22, 2026
8-K items 7.01, 8.01, 9.01
Investor disclosure (Regulation FD); Other event · Current report
Jun 17, 2026
Nov 13, 2025
8-K items 2.02, 7.01, 9.01
Results released; Investor disclosure (Regulation FD) · Current report
Aug 12, 2025
8-K items 2.02, 7.01, 9.01
Results released; Investor disclosure (Regulation FD) · Current report
Jun 18, 2025
8-K items 5.02, 5.07
Officer or director change; Shareholder vote · Current report
Jun 12, 2025
May 28, 2025
8-K items 7.01, 8.01, 9.01
Investor disclosure (Regulation FD); Other event · Current report
40 of 288 shown
Every row opens the filing on EDGAR. The plain words are the site's own for each form and each 8-K item; the complete history, insider forms included, is on EDGAR.