Terms of the deal were not disclosed.
DeltaNet, based in Anaheim, California, has "several thousand" business customers, according to Concentric. It provides Web hosting, as well as dial-up Internet access. DeltaNet also has teamed up with local real estate companies to provide high-speed Net access via copper wires--a technology dubbed ADSL--to multi-tenant commercial buildings.
"Concentric now has a commanding position in the largest regional market in the United States, through its acquisition of InterNex in Northern California and DeltaNet in Southern California," Concentric chief executive Henry Nothhaft said in a statement.
The InterNex purchase price was about $23.9 million, including a $15.5 million cash payment and assumption of $8.4 million of InterNex's liabilities, Concentric said in a recent regulatory filing.
Concentric will integrate DeltaNet's network into its own.
Despite its expansion, Concentric faces intense competition from other regional and national ISPs, which are pursuing similar strategies.
"The company has incurred net losses, and experienced negative cash flow from operations since inception, and expects to continue to operate at a net loss and experience negative cash flow at least through the remainder of 1998," the company said in the filing.