NORTH BAY ? The tech bubble may have burst long ago, but much of the wealth generated in those heady times has remained in the area, according to a recent study showing nearly 20 percent of North Bay households with liquid assets more than $500,000.

Data compiled by a division of Gallup for United States Trust Co. in conjunction with a recent survey of affluent Americans revealed that 23 percent of Marin County's 100,009 households had $500,000 or more in assets, not including their home. Meanwhile, 17 percent of Sonoma County's 175,241 households and 18 percent of Napa County's 48,407 households have reached that benchmark.

Other California counties with considerable wealth are Santa Clara at 19 percent, Orange at 17 percent and Ventura at 18 percent. San Francisco came in at 13 percent, Los Angeles at 12 percent.

This number of wealthy households in the North Bay runs counter to the notion that most residents have the majority of their net worth tied up in their homes, a conclusion not surprising to North Bay Angels founder Steve Weiss.

"Professionals from the Bay Area, California and the rest of the country decide to make this their place of residence in retirement," he said of the North Bay. "And that brings an incredible assortment of talent to the area. And of course they bring their intellectual and financial wherewithal with them."

Mr. Weiss said that since the inception of his investment group in 1998, it has had no trouble maintaining a membership list of 80 to 100 members throughout. All members are SEC-accredited investors, which by definition means they have access to a substantial amount of liquid assets.

According to Robert Eyler, chair of the Sonoma State University Economics Department, much of the wealth present in the North Bay is a holdover from the days of the tech boom of the late 1990s.

"And there was also a lot of money made by the average ... citizen with his stock portfolio. People who cashed out before the tech bubble burst," Dr. Eyler said.

One of the side effects of this large concentration of capital, Dr. Eyler said, is the increasing availability of banking and wealth management services in Marin, Napa and Sonoma counties.

"Those services migrate to where the money is," Dr. Eyler said. "And believe me, the people here are going to want personalized service. They want to shake a hand over a deal rather than invest in with JP Morgan with their broker in New York City. And all of those wealth management service providers have moved to the area because of that wealth that's forecasted to continue to grow."

One less savory trend of the large concentration of assets in the North Bay, Dr. Eyler said, is something he calls "the wealth effect," where consumers push a lot of their income and even savings into consumer goods like boats, expensive vacations and luxury automobiles.

"It's kind of a sad discussion, but I see a lot of people using their liquid assets on conspicuous consumption," he said. "I think we all know, at least anecdotally, examples of people who have spent beyond their means based on liquidation of wealth."