The last time Banca Monte dei Paschi di Siena SpA bought another lender, it was the beginning of the road to collapse and nationalization.Most Read from BloombergWhat Happened to Hanging Out on the Street?

The surprise move is the latest amid a wave of consolidation in the country’s banking industry in recent months and would create Italy’s third largest entity in the sector.

Mediobanca SpA is opposed to the takeover bid by rival Banca Monte dei Paschi di Siena SpA, according to a person familiar with the matter.