Up to a million people a year may lose out on a tax refund simply because they did not file a federal income tax return.

There is no penalty for failure to file, if you are due a refund. But, if you wait to file a return or otherwise claim a refund, you risk losing a refund altogether. An original return claiming a refund must be filed within three years of its due date for a refund to be allowed in most instances.

After the expiration of the three-year window, the refund statute prevents the issuance of a refund check and the application of any credits, including overpayments of estimated or withholding taxes, to other tax years that are underpaid.