The acquisition, which Mediobanca expects to boost its fee income by 10%, comes ahead of a new three-year strategy that CEO Alberto Nagel will unveil on May 24.
With a focus on software, cloud services, data and fintech, Arma has advised on some 100 transactions over the past five years worth in aggregate more than $85 billion. It ranks first as an adviser on large European software buyouts.
The purchase values Arma at around twice its revenue of some $100 million, a person with knowledge of the matter said.
Mediobanca did not disclose the price of the transaction, saying only it would pay 40% in cash at closing and stagger the rest over four years based partly on Arma's performance.
The remainder can be paid in Mediobanca shares, in which case the transaction's full price would take around 30 basis points off the bank's core capital ratio.
The deal will boost earnings per share, based on last year's figures, Mediobanca said, without elaborating.
"This transaction ... will have a material impact on the Corporate Investment Banking fees pool, increasing by approximately 30%," it said.
The acquisition, which needs clearing from European, UK and U.S. regulators, is expected to close in the autumn.
Arma was founded in 2003 by Paul-Noël Guély, a former head of software and services investment banking at Goldman Sachs, and it employs 36 senior bankers specialised in the digital economy.
To grow its international footprint, Mediobanca in 2019 acquired French M&A boutique Messiér et Associes and last year hired former Santander and Lloyds top executive António Horta-Osório as senior adviser.
