The Della Valle brothers said last month their holding company would offer to buy Tod's shares at 40 euros each, valuing the company at 1.32 billion euros ($1.3 billion).
The offer document will be published on Sept. 23, they said.
BNP Paribas, Crédit Agricole Corporate & Investment Bank and Deutsche Bank are acting as financial advisers and BonelliErede is legal consultant for the Della Valles.
($1 = 1.0171 euros)
(Reporting by Francesca Landini; editing by Jonathan Oatis)