A group of investors in Italian Banca Nazionale del Lavoro opposed to a takeover offer from Banco Bilbao Vizcaya Argentaria has requested that regulators investigate whether the Spanish bank is acting in concert with others to build its share of BNL.

The investor group, known as the "contrapatto", or counterpact, claimed to regulator Consob that BBVA could be acting in concert with investment funds, according to sources close to Consob.