Stop Waste And Misuse by the President Act of 2021 or the SWAMP Act of 2021 This bill requires the President, Vice President, President-elect, Vice President-elect, or an immediate family member of such an official, who, while traveling, stays in a hotel or other establishment providing daily-rate accommodation in which that person has an ownership or financial interest, to reimburse to the Treasury specified expenses. Specifically, Treasury must be reimbursed (1) any amount expended by the Secret Service for protection, and (2) any amount expended for other costs incurred by the government pertaining to that stay.