Federal income tax refunds totaling $1 billion may be waiting for an estimated one million taxpayers who did not file a federal income tax return for 2011, the Internal Revenue Service announced today. To collect the money, these taxpayers must file a 2011 tax return with the IRS no later than Wednesday, April 15, 2015.

“Time is running out for people who didn’t file a 2011 federal income tax return to claim their refund,” said IRS Commissioner John Koskinen. “People could be missing out on a substantial refund, especially students or part-time workers. Some people may not have filed because they didn’t make much money, but they may still be entitled to a refund.”