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.