Atos is to buy Bull in a €620m deal that could create a French global leader in data center security, big data analytics and cloud computing. 

Atos, currently ranked Western Europe’s fifth largest cloud provider, and Bull, ranked tenth, could together rise to become the cloud sector’s second biggest revenue generator after Amazon.

The announcement saw Bull’s share price rise by 22% at Friday's close.

Atos shares climbed 4% to €63 a share.

Atos chairman Thierry Breton said the estimated €80m cost of the merger will be justified as the two companies strengthen their position in a cloud services market that is expanding by 25 to 50% a year.

“This is a major step to anchor our European leadership in cloud, big data, and cybersecurity," Breston said.

"Our 2016 ambition is to become a Tier I  company and the preferred European global IT brand.”

Atos will attempt to marry Bull’s expertise in high-performance computing (HPC), data analytics management and cybersecurity to its own talent for large-scale operations.

Market analyst Kepler Cheuvreux described Bull as a ‘serial disappointer’, which it said was reflected in the low multiple used to calculate Bull’s valuation.

Bull’s enterprise value in the deal was set at nine times the earnings before interest, tax, depreciation and EBITDA ­-  a relatively low rating.

Breton insisted, however, that Atos has the integration and operation experience to make the merger work.

A Kepler Cheuvreux spokesman said that Atos has a good record with succesful mergers and acquisitions.

“We see some rationale in the transaction,” Breton said.