Paycheck Protection Program (PPP) & Employee Retention Credit (ERC)
The Consolidated Appropriations Act (CAA) made retroactive changes to rules regarding the Paycheck Protection Program (including simplification of the forgiveness application process, making expenses using PPP funds tax deductible) and Employee Retention Credit (allowing for both PPP and ERC in 2020, just not on the same payroll dollars).
The Act also established a second round of PPP loans with modified rules, and new ERC parameters for the first two quarters of 2021, as well as ERC for qualified disasters other than Covid.
Here's a quick comparison chart.