About $1.3 billion is sitting in Internal Revenue Service coffers, lost by the more than a million taxpayers who neglected to file a 2005 tax return by April 15, 2009.
About half of the taxpayers who didn't file a 2005 return would have gotten a refund of at least $581, according to the IRS.
In California, about 154,500 people are owed a median refund of $537 (half could expect more, half less), while in Texas, 103,000 taxpayers were owed a median of $624, the IRS estimates.
In Florida, 93,300 taxpayers were owed a median of $609, and in New York, 76,800 taxpayers were owed a median of $639.
If you didn't file a 2006 return, consider doing so soon: The deadline for claiming a refund for that tax year is April 15, 2010, and you must file a return to get a refund.
After that deadline, any unpaid refunds for 2006 are handed over to the U.S. Treasury.
There is no penalty for filing a late return if you have a refund coming to you, the IRS says. But three years after the due date, the statute of limitations runs out and you lose any refond.
You'd think that taxpayers who face big tax bills would be the ones who don't file returns, but that's not always the case. For instance, workers whose incomes fall below the filing threshold may decide to not file, said Michelle Lamishaw, an IRS spokeswoman.
"Maybe (the refund) didn't seem like a lot of money to them, or it seemed like too much bother to file, or they didn't have the right paperwork. Sometimes they may anticipate they wouldn't get a refund, so why bother, but sometimes they're wrong about that," Lamishaw said.
"There are a lot of reasons why people don't file, but it can add up to serious money for some people," she said.
Lamishaw noted that, in particular, filing a 2007 return is important because anyone who wants a stimulus rebate payment must file a tax return.
Note that, if you're eligible for a refund for 2006, the IRS won't send it until you file your 2007 and 2008 returns as well. And, if you have any outstanding taxes owed or other federal debt, such as student loans, the IRS will apply the refund to that debt before sending any money to you.
Tax forms for prior years are available on the IRS Web site at IRS.gov, on the forms and publications page. Or, taxpayers can call 800-TAX-FORM (800-829-3676).
