The second biggest investor of Mediobanca - Banca di Credito Finanziario SpA, Vincent Bollore, said he is happy with CEO Alberto Nagel's management, after Leonardo Del Vecchio, who recently acquired a 6.94% stake in the Italy-based lender, questioned the bank's strategy and management.

Del Vecchio, chairman of EssilorLuxottica SA, said Mediobanca, being a small lender, wasted several M&A opportunities, Reuters reported. Del Vecchio also said the bank excessively relies on its ownership in Generali and Compass Banca SpA, Bloomberg News reported separately, citing Italian newspaper Il Sole 24 Ore.

Nagel also received the backing of another Mediobanca investor, Ennio Doris, who said in an interview with Milano Finanza that his family could increase their stake in the bank to 1% from the current 0.4%. "Despite going through a challenging transformation, Mediobanca never stopped paying out dividends and ... never tapped shareholders for cash," Doris noted.

A source familiar with the situation told Reuters Del Vecchio intends to change governance rules at the Italian lender to have a say in picking the next CEO.

Mediobanca bought a 66% stake in French investment bank Messier Maris & Associés in April. It also reportedly evaluated a potential acquisition of Julius Bär Gruppe AG's Italian asset management unit but a deal was not reached.