Credit rating agencies such as S&P have been cited for contributing to the financial crisis of 2007–08. Credit ratings of AAA (the highest rating available) were given to large portions of even the riskiest pools of loans in the collateralized debt obligation (CDO) market. When the real estate bubble burst in 2007, many loans went bad due to falling housing prices and the inability of bad creditors to refinance. Investors who had trusted the AAA rating to mean that CDO were low-risk had purchased large amounts that later experienced staggering drops in value or could not be sold at any price. For example, institutional investors lost $125 million on $340.7 million worth of CDOs issued by Credit Suisse Group, despite being rated AAA by S&P.