At first known mainly for its sales force automation products,[1] the company expanded into the broader CRM market.

[2] By the late 1990s, Siebel Systems was the dominant CRM vendor, peaking at 45% market share in 2002.

[3] On September 12, 2005, Oracle Corporation announced it had agreed to buy Siebel Systems for $5.8 billion.

Siebel Systems, Inc. began with sales force automation software, then expanded into marketing and customer service applications, including CRM.

Benefiting from the explosive growth of the CRM market in the late 1990s, Siebel Systems was named the fastest growing company in the United States in 1999 by Fortune magazine.