WebEx investors will receive $57 a share in cash, the companies said in a statement today. The offer is 23 percent higher than the Santa Clara, California-based company's closing share price of $46.20 yesterday.

The purchase, the biggest since the acquisition of Scientific-Atlanta Inc. last year, gives Cisco increased access to a market that is growing faster than its traditional business for switches and routers. WebEx's services for holding conferences on the Internet and sharing Web-based documents focus mainly on small and medium-sized companies.

``We can help each other reach more customers around the world,'' Cisco Chief Development Officer Charles Giancarlo said on a conference call.

Cisco, the world's biggest maker of computer-networking equipment, said the purchase won't affect earnings excluding some items in fiscal 2008. The companies said they expect the deal to close in the fourth quarter of Cisco's 2007 fiscal year.

Shares of San Jose, California-based Cisco fell 2 cents to $25.83 at 10:33 a.m. New York time in Nasdaq Stock Market trading. WebEx shares surged 23 percent to $56.64 in Nasdaq trading. The stock had gained 32 percent this year before today.

Spending Spree

The purchase is the second for Cisco this week. The company said on March 13 that it agreed to buy NeoPath Networks to gain the closely held company's storage technology. Other acquisitions this year include Five Across Inc., to add social-networking software, and Reactivity Inc., whose technology helps companies do business on the Internet.

Revenue at WebEx jumped 23 percent to $380 million last year, while net income declined 8.4 percent to $48.6 million. Credit Suisse analyst Jason Maynard in San Francisco estimated 2007 sales of $457 million in a note to clients last month and called the shares ``modestly undervalued.''