The Employee Retention Credit (ERC) is a tax credit program created by the US government to help eligible businesses that were impacted by the COVID-19 pandemic. The rules and requirements for the ERC program are complex, but here are some key points:

1. Eligible employers: The ERC is available to eligible employers, which include businesses that were fully or partially suspended due to a government order related to COVID-19, or businesses that experienced a significant decline in gross receipts (i.e., a decline of 20% or more in gross receipts compared to the same quarter in 2019). The ERC is also available to tax-exempt organizations that meet these criteria.
2. Eligible wages: The ERC is based on wages paid to employees. Eligible wages include wages and compensation paid to employees from March 12, 2020, through December 31, 2021. For 2020, the ERC is based on wages paid from March 12, 2020, through December 31, 2020. For 2021, the ERC is based on wages paid from January 1, 2021, through December 31, 2021.
3. Maximum credit: The maximum credit amount is 50% of qualified wages (including allocable qualified health plan expenses) paid to each employee. The maximum credit for 2020 is $5,000 per employee, and the maximum credit for 2021 is $7,000 per employee per quarter.
4. Additional requirements: Businesses must meet certain additional requirements to claim the ERC, including documentation requirements and limitations on the credit based on other COVID-19 relief programs. For example, businesses cannot claim the ERC for wages paid with funds from a Paycheck Protection Program (PPP) loan.

It's important to note that the rules and requirements for the ERC program can be complex and are subject to change. Businesses that are interested in claiming the ERC should consult with a qualified tax professional or visit the IRS website for more information.