Buffett makes plea for optimism in the US

Billionaire Warren Buffett wants Americans to be optimistic about the country’s future but wary about borrowing money and the games public companies play with profit numbers they report.

He said in his annual letter to Berkshire Hathaway shareholders that he still believes America’s best days are ahead.

He detailed his company’s 2010 performance in the letter and devoted part of his message to educating investors on key business principles.

He said the financial crisis of 2008 confirmed the dangers of investing with borrowed money because even a short absence of credit can ruin a company.

He also urged investors not to focus on the net income figures companies report because they are easily manipulated through accounting tricks or by selling investments.