ISO exercise in 2016. Company acquired in 2020. Proceeds from shares received in 2021. How to deal with 2021 1099-B, when date listed in box 1c is the 2020 acquisition date?

My husband exercised options (ISO) to purchase shares of his then-employer’s stock back in 2016. The company was acquired in 2020; he no longer worked there. The third party that handled the acquisition (SRS Acquiom) contacted him about relinquishing his stock certificate in January 2021. 

 

He couldn’t find the certificate, so he did an attestation that the cert was lost. He eventually received a check for the proceeds from the sale of his shares in October 2021.

 

We have received a 2021 1099-B from SRS Acquiom, but we cannot enter this sale because the “date sold or disposed” date in box 1c is in December 2020 (the date of the acquisition). TT is telling us that the date sold is not valid.

 

In case it helps, these are all the 1099-B boxes that are filled in, aside from the proceeds in box 1d:

 

Box 1c: 12/10/2020 — the date the acquisition closed

Box 5: Is checked (noncovered security)

Box 6: Gross proceeds reported to IRS

Box 9: Unrealized profit or (loss) on open contracts — 12/31/2020

Box 10: Unrealized profit or (loss) on open contracts — 12/31/2021

 

Any advice on how to handle this? Thanks!