The Internal Revenue Service has issued PPP Guidance on repayment of the PPP loan and the Employee Retention Credit which states:

80. Is an employer that repays its Paycheck Protection Program (PPP) loan by May 7, 2020, eligible for the Employee Retention Credit? (updated May 4, 2020)

Yes. An employer that applied for a PPP loan, received payment, and repays the loan by May 7, 2020 (in accordance with the Limited Safe Harbor With Respect to Certification Concerning Need for PPP Loan Request in the Interim Final Rules issued by the Small Business Administration effective on April 28, 2020) will be treated as though the employer had not received a covered loan under the PPP for purposes of the Employee Retention Credit. Therefore, the employer will be eligible for the credit if the employer is otherwise an Eligible Employer. For more information, see Business Loan Program Temporary Changes; Paycheck Protection Program-Requirements-Promissory Notes, Authorizations, Affiliation, and Eligibility (PDF).

Based on the SBA Updated Guidance FAQ #43, the May 7th date referenced by the IRS above should track the SBA Guidance (see below).  Please consult your tax advisor for additional information.

Additional IRS FAQs are available here.

SBA Updated Guidance FAQ #43.: In reference to FAQ #31, reminding a borrower to review the required certification on the Borrower Application Form that “current economic uncertainty makes the loan request necessary to support the ongoing operations of the Applicant,” and that a borrower who repays the loan in full by May 7th is deemed to have made the required certification in good faith, the SBA is extending the repayment date for the safe harbor from May 7th to May 14, 2020. A borrower does not need to apply for any extension. (Updated As of May 5, 2020 here)