Warren Buffett Tells Stockholders of Search for Investment `Elephants'.

Knight Ridder/Tribune Business News

Mar. 15 -- Omaha investor Warren Buffett says market conditions are making it tough for him to find the investment "elephants" that will increase his company's value.

Buffett, billionaire chairman of Berkshire Hathaway Inc., told his stockholders Saturday that he must find big investments to meet his goal of increasing the real value of Berkshire Hathaway Inc. by 15 percent a year.

Berkshire's net worth of $57.4 billion is the largest in corporate America, wrote Buffett, the nation's second-richest person. Even so, that figure needs to double within five years if Berkshire is to achieve its 15 percent goal.

"Earning this daunting 15 percent will require us to come up with big ideas: popcorn stands just won't do," Buffett wrote in his annual letter to Berkshire stockholders, which was posted Saturday on the Internet. "Today's markets are not friendly to our search for `elephants,' but you can be sure that we will stay focused on the hunt.'"

In his wide-ranging annual letter to shareholders, Buffett criticized what he said was a growing trend of dishonest and deceptive accounting practices by major corporations.

He also told investors that he made a "very big mistake" by…