This is a bookkeeping issue and not a tax issue.
The forgiven PPP Loan amount is an increase to the holder’s tax basis for purposes of calculating tax basis under Section 705 and Section 1376, (i.e., for partners’ interests in partnerships and shareholders’ stock of S Corporations, respectively),
This eliminates the potential that the forgiven PPP Loan amount would indirectly be taxed as capital gain upon a future disposition of the holder’s partnership interest or S corporation stock.