US credit rating agencies will face tighter supervision¹ under new rules adopted by the US financial watchdog.

美国金融监督机构采用新规则，将会对信用评级机构采取更严格的监管。

The US financial watchdog wants to clamp down on some trading practices

The Securities and Exchange Commission (SEC) said agencies must disclose（揭露） more information on past ratings to help investors² make informed judgements.

The agencies, which give firms ratings to determine how safe an investment they may be, have been criticised for their role in the financial crisis.

The dominant³ agency firms include Standard & Poor's, Moody's, and Fitch.

'Flash trading' moves

Head of the SEC, Mary Schapiro, said that investors' reliance on agency ratings "did not serve them well over the last several years".

Earlier this year, credit rating agencies admitted errors were made when assessing（估定，评定） some of the financial instruments that have been blamed for the credit crunch⁴（信用紧缩）.

The agencies have been accused of failing to spot the size and risk of the bad US housing debt that was resold around the world, causing multi-billion-pound losses.

They gave high ratings to sub-prime mortgage（抵押） investment vehicles that later turned out to be incorrect.

The SEC also proposed rules to ban "flash trading" - the process where certain financial institutions（金融机构） gain access to trading information seconds before it is made public.