Initially with the CARES Act, employers could choose to apply for PPP or claim ERTC credits, but not both.
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PPP was more beneficial than ERTC for most businesses (for reasons we won’t go into here) and so most businesses with under 500 employees received forgivable PPP Loans.
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On March 11, 2021, The American Rescue Plan Act of 2021 was signed into law and included many modifications and expansions to existing elements of previous stimulus programs.
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Noteworthy modifications for business owners included:

Businesses who applied for and received PPP funds could now also claim ERTC credits.

ERTC credits could be retroactively claimed for businesses that qualified in 2020.

ERTC credits were extended through 9/30/21 with lower qualification requirements.

The per-employee cap on qualifying wages increased from $10,000 for all of 2020 to $10,000 per quarter for the first 3 quarters of 2021.

The refundable credit amount increased from 50% of qualifying wages in 2020 to 70% in 2021.
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So the short answer is “Yes” . . . you can claim ERTC even if you received PPP funds.