The Securities and Exchange Commission voted unanimously to propose tougher regulations for credit raters, a step toward reining in an industry blamed for fueling the financial crisis.

The package of proposals, which runs more than 500 pages, aims to arm investors with more details about individual ratings and make it easier for them to compare raters' performance. It also aims to prevent ratings from being tainted by salespeople who market them to issuers or by credit analysts who may be seeking a job with an issuer they are rating.