Shares in Franco-Dutch IT security firm Gemalto have soared after French technology consulting firm Atos offered to buy it for $5 billion.Gemalto, the world's largest maker of chips found in mobile phones and credit cards, has been under financial pressure after posting four profit warnings in a year and having missed a chance to strengthen its security business through a large acquisition.The combination would strengthen Atos in the burgeoning so-called Internet of Things (IoT) sector of internet-connected machinery and household devices able to collect and exchange data using embedded sensors and European payment services on top of digital security, it said.Shortly after issuing the formal offer, Atos Chief Executive Thierry Breton said he had already received the backing of Gemalto's biggest shareholder, France's state-owned investment bank Bpifrance.”I've met the main shareholders and Bpi in particular,” Breton said in a call with reporters following the announcement of the unsolicited bid for Gemalto.”Bpi is not only favorable to this operation of European consolidation, but it also authorized me to tell you about it,” he added.Bpifrance holds 8.51 percent of Gemalto's shares, according to the group's last annual report.At time of press, Gemalto's shares had risen over 35%.