The board of Mediobanca said Banca Monte dei Paschi di Siena’s offer would destroy value for shareholders of both banks.

Monte dei Paschi, Italy’s oldest bank, launched a 13.3 billion-euro ($13.9 billion) takeover bid last week for larger Milan-based peer Mediobanca that aims to reshape the Italian banking sector. Monte dei Paschi said that the tie-up would generate 700 million euros ($733 million) a year in pretax synergies, and deliver significant profits.

Mediobanca SpA has rejected Banca Monte dei Paschi di Siena SpA’s takeover bid, turning the unsolicited approach into a hostile one.