Italian bank Mediobanca on Tuesday rejected a takeover offer by state-backed rival Monte dei Paschi di Siena , saying a tie-up would be detrimental to its shareholders because it lacked any strategic and financial rationale.

Mediobanca’s board will meet on Tuesday morning to evaluate the unsolicited approach, which has garnered government support but so far failed to win over investors and analysts.

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.