0001453687 2021-01-01 2021-12-31 0001453687 2021-06-30 0001453687 2022-04-22 iso4217:USD shares true 2021 FY 0001453687 10-K/A true 2021-12-31 --12-31 false 001-37798 Selecta Biosciences, Inc DE 26-1622110 65 Grove Street, Watertown, MA 02472 617 923-1400 Common Stock, $0.0001 par value per share SELB NASDAQ No No Yes Yes Non-accelerated Filer true false false false 366839496 151809416 Auditor Name: Ernst & Young, LLP Auditor Location: Boston, Massachusetts 42 This Amendment No. 1 on Form 10-K/A, or the Form 10-K/A, is being filed by Selecta Biosciences, Inc., or Selecta, in order to disclose information required by Items 10, 11, 12, 13 and 14 of Part III of Form 10-K, which information was omitted from Selecta’s Form 10-K for the fiscal year ended December 31, 2021, or the Original Form 10-K, in reliance on Instruction G to Form 10-K. The Original Form 10-K was filed with the Securities and Exchange Commission, or SEC, on March 10, 2022.