CHICAGO (AP) — Chicago businesswoman Penny Pritzker has resigned from the Chicago Board of Education.

Pritzker is a leading candidate to be the next U.S. Commerce Secretary. She is a longtime ally of President Barack Obama and was a top fundraiser during his 2008 and 2012 campaigns.

Pritzker did not mention the potential Cabinet post or give a reason for her resignation in a letter to Mayor Rahm Emanuel Thursday. She thanked Emanuel for the opportunity to serve and said she “wholeheartedly” supports the work he’s doing to improve Chicago schools.

In a statement, Emanuel said called Pritzker “a true leader in her every business, civic and philanthropic endeavor.”

She is an heir of the Pritzker family that founded the Hyatt chain of hotels. She was Obama’s campaign finance chairwoman in 2008.

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