MILAN - Silvio Berlusconi's resignation deals a blow to the billionaire prime minister's family business which analysts say has always profited from his political role.

The verdict of the Italy's main stock exchange cannot have been clearer as his already struggling Mediaset television group plummeted 12 percent in Milan on Wednesday, a day after he announced he would step down.

A feeling that the end is nigh has long been anticipated as Mediaset shares plunged 49 percent in six months, when Milan stocks fell only 30 percent in the same period.