Last month, I posted on 2008's eight worst ideas. At the top of my list was deregulation. Robert Rubin, who spent a decade as a director of Citigroup (NYSE: C) and is now retiring, is partly responsible for one very important act of deregulation -- the repeal of Glass-Steagall which separated investment and commercial banking. (It was former Citi CEO Sandy Weill's 1998 merger of his Travelers with Citi that spurred Glass-Steagall's repeal in the 1999 passage of the Gramm-Leach-Bliley Act which allowed commercial and investment banks to own each other.)

And by bringing down that barrier -- established in the wake of the stock market manipulations of the 1920s enabled by commercial banks that made margin loans to trade stocks -- the U.S. helped usher in the current financial catastrophe. Now the government is gradually reimposing Glass-Steagall -- in effect, if not in law.

Rubin was well rewarded for his decade of "service" to Citi -- taking in $126 million and being paid as an employee while claiming to be a mere advisor. But for that measly sum, Rubin's reputation -- which was at its zenith following his tenure as Treasury Secretary in the 1990s -- is shredded. It probably didn't help that since he joined Citi's board in October 1999, its stock has fallen 82% -- destroying $164 billion in stock market value. Meanwhile, the empire that Weill ushered in -- based on the idea that people wanted to buy all their financial services from one provider -- is being dismantled.

This post is part of our feature on Money Losers of 2008. See all 20.

There's no doubt about it -- times are tough. People are struggling to find work and to pay the bills as the value of their homes and savings dwindle. The poor get poorer, and the rich get richer.

Or do they? It's all relative, of course, but world's billionaires have been taking some big hits too. We take a look at Sheldon Adelson, Kirk Kerkorian, and Lakshmi Mittal in their own separate posts, but here are some other billionaires who have lost billions this year (courtesy of Forbes and Business Sheet).

• Brothers Anil and Mukesh Ambani of India's private conglomerate Reliance lost $32.5 billion and $28.2 billion, respectively.
• Warren Buffett, the Sage of Omaha, lost $16.5 billion. Shares of Berkshire Hathaway Inc. (NYSE: BRK.A) are down about 32% since the beginning of the year.
• Microsoft (NYSE: MSFT) founders Bill Gates and Paul Allen lost $12.3 billion and $2.6 billion, respectively, while CEO Steve Balmer lost $6.5 billion. Shares of Microsoft are down 46% since the beginning of the year.
• Larry Page and Sergey Brin, cofounders of Google Inc. (NYSE: GOOG), lost $11.9 billion and $11.7 billion, respectively, and CEO Eric Schmidt lost $3.8 billion. The share price of Google has fallen 55% since the beginning of the year.
• Larry Ellison, CEO of Oracle Corp. (NASDAQ: ORCL), lost $8.2 billion. Shares of Oracle are down 21% since the beginning of the year.
• Media maven Sumner Redstone lost $7.2 billion. Shares of his private investment firm National Amusements fell 70% this year.