It is indeed true that most of the headlines are focused on the current third round of coronavirus stimulus checks sent out under President Joe Biden’s American Rescue Plan.

But what many cash-strapped Americans might not be aware is that the Internal Revenue Service is holding onto a hefty sum of tax refunds from previous years. Just last month, the agency confirmed that $1.3 billion in tax refunds remain unclaimed for an estimated 1.3 million U.S. taxpayers who have yet to file their 2017 tax returns.

The bad news is that these individuals only have one week left to collect the money.

“Time is quickly running out for these taxpayers. There’s only a three-year window to claim these refunds, and the window closes on May 17,” IRS Commissioner Chuck Rettig recently said in a statement.

“We want to help people get these refunds, but they will need to quickly file a 2017 tax return,” he added.

The IRS has estimated that the midpoint for the potential refunds for 2017 is $865—which means that “half of the refunds are more than $865 and half are less,” the agency stated.

If the money remains unclaimed past the deadline, it will become the property of the U.S. Treasury.

The IRS has reminded “taxpayers seeking a 2017 tax refund that their checks may be held if they have not filed tax returns for 2018 and 2019. In addition, the refund will be applied to any amounts still owed to the IRS or a state tax agency and may be used to offset unpaid child support or past due federal debts, such as student loans.”

For this particular tax season, the IRS has noted that it has received more than ninety-three million individual tax returns and more than sixty-two million refunds have been disbursed. The average refund to date has been estimated to be $2,900.

However, with new tax codes to implement and more than a hundred sixty million stimulus checks being sent out, the agency has found it increasingly difficult to quickly get these refunds into taxpayers’ hands. Moreover, according to the National Taxpayer Advocate, the IRS is holding nearly thirty million tax returns for manual processing, which is only further delaying the refunds.

Know that for many early filers, there have been reports that the average wait time for a refund has been about six to eight weeks, which is much longer than the usual wait of three weeks or less.

For those individuals who have already filed their tax returns, be aware that there are ways to track the refunds. Two of the most popular options are the IRS tool Where’s My Refund and the mobile app called IRS2Go.

Ethen Kim Lieser is a Minneapolis-based Science and Tech Editor who has held posts at Google, The Korea Herald, Lincoln Journal Star, AsianWeek, and Arirang TV. Follow or contact him on LinkedIn.