In another major acquisition of a rival software maker, Oracle on Monday said it will buy up Siebel Systems in a deal valued at over $5.8 billion. Siebel, a maker of customer resource management software, will provide Oracle with 4,000 new customers and 3.4 million CRM users.

Oracle CEO Larry Ellison said the deal was intended to give Oracle an entire ecosystem of enterprise application software, and was pushed by companies such as General Electric who only wanted to deal with a single vendor.

Oracle is offering $10.66 for each share of Siebel stock, which amounts to a 17 percent premium.

"This deal is good for Oracle shareholders and customers," Ellison told analysts and reporters in a conference call. "Many of our largest customers like G.E. have encouraged the two companies to get together."

The deal was apparently in the works for quite some time, but Oracle opted to first complete its integration with PeopleSoft. Oracle bought PeopleSoft after a drawn out battle with the company's board for $10.3 billion.

Ellison says Siebel will become the focus of Oracle's CRM offerings. "Siebel will be the centerpiece of our CRM strategy going forward," he said. "We will continue to sell PeopleSoft CRM, Oracle CRM, but Siebel will be the centerpiece."

Siebel joins a flurry of recent acquisitions by Oracle, which include Retek, ProfitLogic and Indian banking company I-flex Solutions.