Lansing, MI — Michigan will start allowing people to claim a state income tax deduction for gambling losses they claim on their federal tax return. The law, enacted by Gov. Gretchen Whitmer last week, is effective for the 2021 tax year and beyond. It is expected to reduce state tax revenue by $12 million to $17 million a year. Federal law allows gambling losses to be deducted by those who are able to itemize their deductions.