Banca Monte dei Paschi di Siena SpA has ended up with an overwhelming majority in Mediobanca SpA, giving it almost complete ownership of the Milan-based rival. 
Mediobanca investors committed 86.3% of the shares after the tender period had reopened from Sept. 16 through Sept. 22, according to a Borsa Italiana filing Monday. The previous period, which ended on Sept. 8, had left Monte Paschi with 62.3%.
The deal, worth more than €17 billion ($20 billion) at Monday’s market close, is set to create Italy’s third-largest lender by assets. Monte Paschi Chief Executive Officer Luigi Lovaglio overcame fierce resistance from ...