PPP Extension Act of 2021 This bill extends the Paycheck Protection Program, established to support small businesses in response to COVID-19, through June 30, 2021. Currently, the program is set to expire on March 31, 2021. For the final 30 days of the program (i.e., from June 1 until June 30), the Small Business Administration (SBA) may only process applications submitted prior to June 1, and it may not accept any new loan applications. The bill also prohibits the SBA from prioritizing certain applications over others.