Italy\'s state-owned defence company Finmeccanica, carmaker Fiat, and media companies Mediaset and RCS are amongst the traded entities investors have taken short positions in, according to information released by Italian stock market watchdog Consob on Friday. On Thursday an EU regulation came into effect controlling the short selling and certain aspects of credit default swaps for the entire European Union. Others companies include Monte dei Paschi di Siena, the world\'s oldest bank, Italian insurance company Assicurazioni Generali, and tire company Pirelli, according to information published on Consob\'s website. Consob began publishing the list of Italian companies hit with \"shorted stock\" that showed the companies with single investors holding net short positions totalling more than 0.5% of the traded shares.