Large banking companies such as Wells Fargo & Co. and Bank of America Corp. are well established there, and nearly a dozen banks catering largely to commercial customers have opened there in the last decade. If Business Bank fares well with the new product, which it began offering last week, the $15 billion-asset City National may roll it out in its California market, Mr. Phillips said. Business Bank is a wholly owned subsidiary of the Los Angeles company, but by April, City National plans to merge it into its flagship City National Bank. It bought the Nevada bank on March 1 for $167 million. Lana Chan, an analyst at Bank of Montreal's BMO Capital Markets in New York, said Business Bank is smart to try out the idea first. "Nevada is definitely a good testing ground — it's a relatively small piece of their banking franchise right now."