Chicago 2016 CEO Pat Ryan's message to taxpayers and the city council is that it's unlikely the games would cost the city money.
Some aldermen and voters have their doubts.
"My constituents have told me we need more information. We're generally supportive, but we need to know the details," said Ald. Tom Tunney, 44th Ward.
The mayor and the bid committee are confident an insurance plan will cover any financial overruns.