MILAN (Reuters) - Unipol Chairman Carlo Cimbri said on Friday a foreign bank was studying a potential bid for Popolare di Sondrio to rival the one unveiled by Italy's BPER Banca.

Insurer Unipol is the leading shareholder in both BPER and Pop Sondrio and has thrown its weight behind BPER's bid for Pop Sondrio.

Speaking at the presentation of Unipol's multi-year plan, Cimbri hinted at Dutch bank ING as a possible suitor by saying the bank interested in Pop Sondrio was the colour of a journalist's tie, which was orange.

ING did not immediately respond to a request for comment.

Cimbri said Unipol could be open to considering rival bids for Pop Sondrio.

Asked about unconfirmed rumours of foreign interest for the bank, Cimbri said: "It looks like a foreign group has hired lawyers and advisers to study a potential deal for Popolare di Sondrio: it's totally legitimate. We're an investor and if someone else makes a spectacular bid it's not like we've promised eternal love, we don't pick sides."

"We don't have eternal friends or eternal foes, only our interests are eternal: ... we're open to any proposition."

(Reporting by Andrea Mandala; Writing by Valentina Za, editing by Gavin Jones)