More than one million Americans have until April 15, 2025, to claim tax refunds and stimulus payments from 2021. The IRS estimates that over $1 billion remains unclaimed, with individual refunds averaging $781. Those who did not file a 2021 tax return could be eligible for a Recovery Rebate Credit of up to $1,400. If unclaimed, these funds will revert to the U.S. Treasury. The IRS urges taxpayers to act quickly before time runs out.