Each year the postal Service returns thousands of IRS tax refund checks as undeliverable.
Many checks are undeliverable because the address on the tax return was illegible or incorrect.
Returned checks are redeposited and credited to the taxpayer's account until claimed. An IRS notice is sent to the address of record or the forwarding address given to the Postal Service. If that is also returned, the taxpayer is added to the undelivered refund list. While it is hard to imagine that a taxpayer would forget about an overdue refund, some of the checks are for small amounts, some are unexpected and some are issued after the IRS corrects a taxpayer error. Notices are sent to the address of record or the forwarding address given to the Postal Service.