Warren Buffett, the billionaire chairman of Omaha-based Berkshire Hathaway Inc., said low interest rates and inflation should dissuade investors from buying bonds and other holdings tied to currencies.

"They are among the most dangerous of assets," Buffett said in an excerpt of his annual letter to shareholders that appeared Thursday on Fortune magazine's website. "Over the past century these instruments have destroyed the purchasing power of investors in many countries, even as these holders continued to receive timely payments of interest and principal

Buffett said investors should avoid gold because its uses are limited and it doesn't have the potential of farmland or companies to produce new wealth. Achieving a long-term gain on the metal requires an "expanding pool of buyers" who believe the group will increase more, he said.