In an interview with Il Sole 24 Ore daily, Unipol CEO Carlo Cimbri said the idea of a combination of the mid-sized banks to create a group with 300 billion euros ($356.43 billion) in assets, rooted in the wealthy north, was "fascinating."

"Media say Banco BPM is studying options. Were it to prioritise this idea, I think BPER couldn't but analyse it with great attention," Cimbri said.

"A project that creates value and is consistent with shareholders' interests would have their backing and that of the market," Cimbri said.

Unipol, which controls insurer UnipolSAI, is the single largest investor in BPER with a 19% stake.

Unipol has steered BPER onto an expansion path by backing the acquisition of 486 branches and 134 operating outlets, with relative assets, from the group born from the merger of Intesa Sanpaolo and UBI Banca.

With Unipol's help BPER just raised 800 million euros in cash to fund the acquisition. It has said it will consider further M&A once it has integrated the new business.

Intesa's surprise takeover of UBI earlier this year has forced rivals to study possible countermoves.

Banco BPM CEO Giuseppe Castagna has repeatedly said the bank is open to considering potential partners following the creation of the Intesa-UBI banking "behemoth".

(Reporting by Valentina Za; editing by Agnieszka Flak)