Advisory group Rothschild's Italian unit has never advised Monte dei Paschi di Siena on any capital measure linked to the acquisition of smaller peer Antonveneta from Santander, it said on Sunday, denying a press report.
In a statement Rothschild SpA said it had only advised Santander in the sale.
It said it would take legal action against Italian newspaper La Repubblica which published the report on Sunday.
Monte Paschi, Italy's third largest bank, is under investigation over its 9-billion-euro cash acquisition of Antonveneta from Santander in 2007.
Santander had bought Antonveneta for 6.6 billion euros in a three-way break-up bid for Dutch bank ABN AMRO, and almost immediately sold it on to Monte dei Paschi, netting a hefty gain.
(Reporting By Danilo Masoni)