Warren Buffet, the largest shareholder in Moody's Corp, on Wednesday defended the rating agency, saying they had made the same mistakes as other market players ahead of the financial crisis.

The Financial Crisis Inquiry Commission, chaired by former California state treasurer Phil Angelides, is probing how triple A credit ratings were assigned to structured credit products that proved to be riddled with bad loans.

Asked whether the agency’s management should be changed because the ratings had to be downgraded substantially during the housing collapse, Mr Buffett said: “I would say in this particular case that they made a mistake that virtually everybody in the country made.

“There was the greatest bubble I’ve ever seen in my life … Very, very few people could appreciate the bubble and that’s the nature of bubbles,” he said. He added: “Rising prices are a narcotic that affect the reasoning power up and down the line.”

Ray McDaniel, chief executive of Moody’s, who appeared alongside Mr Buffett, said that failures in rating securities properly were deeply disappointing. ”It is injurious to the reputation of the firm and to the long-term value of the firm,” he added.