Don't toss that letter from Montana. It could be your Minnesota tax rebate.

Minnesotans expecting a tax rebate check to arrive this month should keep an eye out for a piece of mail coming from Montana.

The state of Minnesota worked with a vendor called Submittable Holdings, Inc. in Missoula to get the checks sent to taxpayers' homes, which has caused some confusion from people who received them in the mail.

The Star Tribune received several emails from individuals about the return address on the checks, and the state Department of Revenue has been contacted by Minnesotans wanting to confirm that they are legitimate.

Department of Revenue spokesman Ryan Brown said the department worked with Submittable and U.S. Bank to issue the payments because they've been vetted and approved on past projects — including the frontline-worker checks program — so the state is familiar with their process and security.

The checks list Submittable Holdings c/o State of Minnesota, PO Box 8289, Missoula, MT 59807. A description with the check describes it as the "State of Minnesota 2021 Tax Rebate Program."

The department paid Submittable $21.5 million — money allocated in the tax bill passed last session — for deposits, check processing, payment reconciliation, customer support and a secure online portal, in coordination with U.S. Bank.

The DFL-controlled Legislature passed the one-time rebate checks this spring as part of a $3 billion tax package that also cut Social Security taxes and created a new child care tax credit for low-income families. It also raised $1 billion in taxes on some corporations and wealthier Minnesotans.

Individuals with an adjusted gross income of up to $75,000 in 2021 are eligible for $260, while married filers with an income of up to $150,000 could get $520. Families can get an additional rebate check for up to three dependents, for a maximum of $1,300.

The state is sending out the rebates in two waves. Direct deposits started last month for those with updated banking information with the state. Paper checks will take longer and be sent through September. The state estimates more than 2 million payments totaling $1.1 billion will be sent out.

The checks are not subject to state taxes, but it's not yet clear if they will be federally taxable.

The Department of Revenue is encouraging Minnesotans who believe they're eligible but haven't received a deposit or a paper check by mid-September to contact the department.