Mr Buffett has not escaped the credit crunch unscathed
Warren Buffett, long revered for his investment prowess, has admitted that even he made some "dumb" mistakes during the past year.
In his annual letter to investors in his company Berkshire Hathaway, he said the errors included buying stakes in two Irish banks.
He also regretted investing in oil company Conoco Philips when the crude price was at its peak.
Berkshire's profits fell 62% in 2008 - the worst performance in its 44 years.
The company's net earnings totalled $4.99bn (£3.5bn) in 2008 compared with $13.2bn in 2007.
In the letter to shareholders, Mr Buffett was candid about his failings, saying "the tennis crowd would call my mistakes 'unforced errors'."
"During 2008, I did some dumb things in investments," he said.
"I in no way anticipated the dramatic fall in energy prices that occurred in the last half of the year," he added.
Mr Buffett said he also spent $244m on stock in two Irish banks that appeared cheap but have since declined sharply.
He predicted that the US economy would be in a "shambles" throughout 2009 and beyond.
However, he added that this did not have any bearing on whether stock markets would rise or fall.
Mr Buffett blamed the sub-prime mortgage debacle on salesmen, ratings agencies and investors who relied on complicated and flawed models.
"Beware of geeks bearing formulas," he said.
He had a more old-fashioned view on the merits of home ownership.
"My family and I have enjoyed my present home for more than 50 years, with more to come"
"Enjoyment and utility should be the primary motives for purchase, not profit," he said.