Milan says it faces losses of millions of euros as a result of the deal
Four major banks have been ordered to stand trial in Italy in a fraud case related to derivatives trading.
JP Morgan Chase, UBS, Deutsche Bank and Germany's Depfa bank have been told they will be tried for aggravated fraud, along with 13 other people.
The charges relate to the sale of derivatives to the city of Milan.
JP Morgan denied employees involved had acted inappropriately, while Deutsche and UBS also denied any wrongdoing. Depfa was not available for comment.
Prosecutors say the trial, which is due to begin in May, is an important test case for hundreds of Italian cities who have lost money through similar deals.
The arrangements between banks and cities, including Milan, were designed to reduce interest payments on their loans.
In the case of Milan, the four banks are accused of misleading the city authorities when they agreed a derivatives deal on a 1.68bn euro ($2.31bn; £1.51bn) loan in 2005.
The deal adjusted the interest payments on the loan - a move which Milan says leaves it facing a 100m euros loss.
Two former Milan city officials have also been ordered to stand trial, along with 11 bank employees.