The Internal Revenue Service is looking for more than 5,000 county residents who are due to receive a combined $11.3 million in undelivered tax refund checks. These are refunds that could not be delivered because of mailing address errors.
In Los Angeles County, refund checks average $2,145. The national average is $1,471 this year, compared to $1,148 last year, an increase of over 28 percent due, in part, to recent changes in tax law which introduced new credits or expanded existing credits, such as the Earned Income Tax Credit.
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“We want to make sure taxpayers get the money owed to them,” said IRS Spokeswoman Anabel Marquez. “If you think you are missing a refund, you should update your address information as soon as possible and hopefully get your money in time for the Holidays.”
A list of local taxpayers with undelivered refunds is accessible here . 
If a refund check is returned to the IRS as undelivered, taxpayers can generally update their addresses with the “Where’s My Refund? ” tool on IRS.gov . The tool also enables taxpayers to check the status of their refunds. A taxpayer must submit his or her Social Security number, filing status and amount of refund shown on their 2009 return. The tool will provide the status of their refund and, in some cases, instructions on how to resolve delivery problems.
While only a small percentage of checks mailed out by the IRS are returned as undelivered, taxpayers can put an end to lost, stolen or undelivered checks by choosing direct deposit when they file either paper or electronic returns. Taxpayers can receive refunds directly into their bank, split a tax refund into two or three financial accounts or even buy a savings bond.
The IRS also recommends that taxpayers file their tax returns electronically, because e-file eliminates the risk of lost paper returns. E-file also reduces errors on tax returns and speeds up refunds.
The public should be aware that the IRS does not contact taxpayers by e-mail to alert them of pending refunds and that such messages are common identity theft scams. The agency urges taxpayers not to release any personal information, reply, open any attachments or click on any links to avoid malicious code that will infect their computers.