Michael Bloomberg, the 8th wealthiest American. (Seth Wenig/AP)How will John Catsimatidis — supermarket billionaire, New York mayoral hopeful and the 215th wealthiest person in America — know when the crisis on Wall Street is over?

"The situation is going to get better when you feel good about buying Citigroup stock," he says. "Right now, nobody feels good about buying it."

With all the turmoil on Wall Street these days, it's easy to get spooked. Miles of newsprint, endless talking heads, pandering candidates and economists quoted up the wazoo — all with opinions, most of them differing.

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One group you haven't heard a lot from, though, are America's richest people — some of the savviest entrepreneurs and financiers on the planet. To get some insight into one of the most unpredictable periods in the history of Wall Street, we asked a handful of these billionaires to tell us about the economic indicators they're watching and what they think will happen next.

Eyes on the assets

Don Marron, former chief executive of PaineWebber and founder of investment firm Lightyear Capital, has his eye on asset sales from troubled banks. In the coming months, Marron, a billionaire who is not on The Forbes 400 list, says they'll be an important gauge of how the economy is faring and how Wall Street is recovering.

Mark Cuban, No. 161 on the list of wealthiest Americans. (Tony Dejak/AP)"You have a number of situations here, notably one company in bankruptcy, where a certain set of assets have to be liquidated, and the market hasn't been tested on these," says Marron. "As a potential buyer, I would want to wait until we see these sales actually take place, and I think others would too."

Will investment banks ever post those eye-popping profits again?

"I think it will be a long time getting back there," says Sam Wyly, who knows something about finance from his hedge fund Maverick Capital.

"One thing that I noticed about two years ago was that financial sector of the American economy had grown to percentages that were greatly disproportionate to history," he said. "The financing part of the economy grew much more than the part that was making and selling something. It will be shrinking at least for a while."

Stabilizing home prices will be a crucial part of the healing process since it will bolster the value of troubled mortgage securities. When does the housing market bottom? Catsimatidis, who has extensive real estate holdings in the New York area, says, "Home prices stabilize when they equal the cost of actually building of home plus the cost of the land plus a premium for location."

Billionaire entrepreneur George Lindemann, the 262nd wealthiest person in America with a fortune of $1.8 billion (US), says we'll see values stabilize much more quickly in some areas than others. "I think that's a regional issue and not a national issue. Houston, for instance, is strong as hell. No vacant jobs, prices are going up and building is continuing."

'If I had the time, I would be researching every company that needs renewable and expandable debt to survive and would short the sh*t out of it.'— Billionaire Mark Cuban

A year ago, Lehman Brothers shares traded for over $60 each. Now they're virtually worthless. Do the problems that totaled the once-mighty Lehman spread to other companies and industries?

"Any company that is built around the need to add debt is in trouble," says Mark Cuban, owner of the Dallas Mavericks and founder of HDNet. He ranks 161st on The Forbes 400 this year with a net worth of $2.6 billion. "The process of deleveraging is industry agnostic. If I had the time, I would be researching every company that needs renewable and expandable debt to survive and would short the sh*t out of it."

One thing that's clear is that despite the turmoil of the times, successful businesspeople have no shortage of ideas where to invest. On Monday, the Atlanta Journal-Constitution reported that one of Warren Buffett's subsidiary companies bought a corporate furnishings division from Aaron Rents.

Drawn to energy

Wyly, a billionaire who is not on The Forbes 400, advises to invest in areas you know are "rock solid." The author of 1,000 Dollars and An Idea likes companies like energy giant BP. He points to its investments in renewable energy, low price-earning multiple and management team.

'You can’t just blame the banks, you also can blame the people that took out mortgages.'— New York mayor Mike Bloomberg

As they say, buy when there's blood on the streets. But that raises another question: Who's to blame for the recent torrent?

Mike Bloomberg casts a wide net. The mayor of New York, former Wall Streeter, and founder of financial services company Bloomberg (which made him the 8th richest person in America with a net worth of $20 billion) told reporters Tuesday that, "You can’t just blame the banks, you also can blame the people that took out mortgages ... We were brought up that you first had to put some savings together and then enjoy. But this whole society has gotten to the fact that we’re a ‘now, give it to me today’ kind of society. I think regulation has not been adequate.

"There’s no one person to blame other than all of us," he added.