A lot of people who fail to file their taxes each year do so because they assume they will have to owe money or won’t be getting anything back. But the IRS says there is nearly a billion dollars in unclaimed returns from 2009, and that it needs to be claimed by April 15, 2013, or it goes into Uncle Sam’s pocket.

Unlike those who file for returns where money is owed, there is no penalty for filing a late return when you’re actually owed a refund.

But there are some catches. If you haven’t filed for 2010 and/or 2011 yet, the IRS might hold on to that refund until you do so. And if you owe anything to the IRS or to your state tax agency, that three-year-old refund may be used to pay off that debt. Same goes for unpaid child support or past due student loans.

Here is the chart to see just how many people are owed refunds in each state:

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