The state announced the change Wednesday. It says the College Board, the administrator of the SAT, won a three-year contract worth $17.1 million.
State officials say the College Board's bid was $15.4 million less than the next bidder and was scored 10 percentage points higher by an evaluation committee of educators.
Michigan has been giving the ACT to 115,000 juniors annually since 2007 as part of the Michigan Merit Examination.
ACT Inc. will continue to provide its WorkKeys assessment for all high school students under a three-year, $12.2 million contract. It's a job skills assessment.
The contracts still need final approval from the State Administrative Board.