"I was making far more money than they were," Abramoff recalled. "So I wasn't as impressed as perhaps they thought I'd be."

At the time, Abramoff, who was involved in an extensive corruption ring, didn't think much of it. But after years in prison to reflect on the culture of corruption in Washington, Abramoff says he thinks trading based on inside Congressional knowledge is wrong.

"These people should not be using whatever information they gain as public servants to benefit themselves, any more than they should be taking bribes," he said.

Generally, however, legal analysts say that Wall Street insider trading laws do not apply to Congress. As an open and public institution, the legal assumption has long been that any member of the public can have access to information about how Congress works. In practice, though, that's simply not true, as powerful members of Congress come into contact daily with market-moving tidbits. That gap between the law and the reality has made Capitol Hill a virtual free-fire zone for insider trading. Over the years, academic studies have found that members of the House of Representatives beat the market by as much as six percent per year and members of the Senate do even better than that.

And Abramoff says everybody on the inside knew it. "I think it was pretty widely known and it is pretty widely known that it is going on," he said.

Abramoff has been making the rounds, speaking with the media this week, to promote his new book, "Capitol Punishment: The Hard Truth About Washington Corruption From America's Most Notorious Lobbyist," which went on sale Monday.

Abramoff said that the most valuable type of information for Congressional insider trading is held by congressional investigators who pry deeply into corporate goings on. A particularly easy target is advance knowledge of the announcement of an investigative hearing into a company.

"Hearings under almost every circumstance are going to have a bad impact on a company," Abramoff said. "And so some staffers I've seen in the past talking about the fact that, 'Oh, I'm gonna go out and short that company.'"

But the man who spread millions around the nation's capital said he didn't like to invest his own money in the stock market. "I'd never really played the stock market," he said. "I viewed it as a big gamble because of the fact you don't have all the information you need. The casino has all the information, and you don't."

Follow Eamon Javers on Twitter: @EamonJavers and Facebook