10. Taleo, $375 Million (analyst estimates)
CEO: Larry Ellison, Oracle
Now a business unit of Oracle, Taleo is a cloud-based human resources application suite focused on a variety of features, including recruiting, on-boarding, performance management, succession planning, analytics, and compensation. Oracle has been trying hard to build a name for itself in the cloud, given the company's long-standing footprint in the world of traditional software. The acquisition is largely viewed as a counterweight to SAP's acquisition of SuccessFactors, which follows next in the countdown.