Consob, the Italian financial markets regulator, has agreed to investigate the share ownership of Banca Antonveneta, the subject of a €6.3bn ($8.1bn) proposed bid by ABN Amro.

The regulator's probe comes as Reuters reports that the Italian media claims Banca Popolare di Lodi could already control 30% of Antonveneta in concert with a number of investors said to include Stefano Ricucci, an Italian businessman.