For Werner Brandt, CFO of enterprise software company SAP, the biggest challenge of the past few years has been executing, financing and integrating a steady stream of acquisitions. SAP purchased Business Objects for $6.7 billion in 2008, Sybase for $5.8 billion in 2010 and SuccessFactors for $3.4 billion earlier this year. And in May, it agreed to acquire e-commerce company Ariba in a deal valued at $4.3 billion.

When it comes to integrating acquisitions, there is no one-size-fits-all, Brandt says. "One of the learnings for us was that it is good to treat every acquisition differently from an integration perspective, depending on the reasons for the acquisition itself."

"For example, we implemented Business Objects into SAP straight away because from a product and solution perspective, it was an enhancement of SAP's existing solution," Brandt says. "In the case of Sybase, we acquired a company which was very strong in the mobile and database business—fields we wanted to expand in—and we decided to integrate in phases over two years."