SAN FRANCISCO – Mike Maples says he came to Silicon Valley from Texas in 2005 as a “washed-up” corporate-software executive aspiring to be a venture capitalist. Unable to land a job with a half-dozen firms, he put his own money to work.

Five years later, his stakes in Twitter Inc., Digg Inc., SolarWinds Inc. and Chegg Inc. have turned Maples into a celebrity on Menlo Park’s Sand Hill Road, where he’s investing alongside the same firms that didn’t make him a partner. And he’s turning a profit while the rest of the industry slumps.

Venture firms have lost an average of about 1 percent annually over the past decade, according to Cambridge Associates.

Maples’ $25,000 investment in Twitter four years ago had multiplied by 26 times as of September, and his $500,000 stake in textbook rental company Chegg may be up even more. By catching companies at their earliest stages, sometimes before they have business plans, Maples is buying on the cheap. He also makes smaller investments than firms with billion-dollar funds, letting him tap into startups that need less capital.

“We can do the wacky controversial thing that can’t make it through a venture firm,” said Maples, 42. “If the company is awesome, we’re going to be in early at such a low valuation that it’s just going to cover all sins.”

For Maples, the goal is to find what he calls “thunder lizards,” a term he used at least 18 times in an hour-long interview. It’s a reference to Godzilla, which “was hatched from radioactive atomic eggs and swam across the Pacific and destroyed Tokyo,” Maples said. A thunder lizard is a company that disrupts its industry, earns a 100-fold return and makes up for all of a fund’s bad bets, he says.

Twitter, Chegg and other investments have the potential to be thunder lizards, Maples said. Not all of his bets have panned out, though. B-Side Entertainment, which ran websites for film festivals, closed this year, and the microblogging site Pownce shut down in 2008.

His biggest dud so far was an investment he didn’t make. Maples declined an early opportunity to invest in Zynga Game Network Inc., the maker of Facebook games such as “FarmVille” and “Mafia Wars.” Zynga is now worth as much as $3.3 billion, according to a February report from SharesPost Inc. and Next Up! Research.

Though his Southern twang stands out in Silicon Valley, Maples isn’t a technology outsider. His father, also named Mike, was an executive at Microsoft and IBM. Bill Gates attended his wedding, and Maples studied engineering at Stanford University, near Palo Alto. By the time he returned to California after more than a decade in Texas, Maples had helped take two companies public, including Austin-based Motive Inc., which he co-founded in 1997.