The U.S. Securities and Exchange Commission, while expanding disclosure requirements for one set of asset-backed securities, has stepped back from a plan to shed more light on a major part of the market, Bloomberg reported today. The five SEC commissioners unanimously approved a rule yesterday to offer investors more details on bonds backed by assets such as mortgages and car financing, including specific data on individual loans, and new practices such as a cooling-off period to review documents before certain bond sales. Dropped from the rules: A requirement that issuers of private securities be ready to furnish to buyers the same type of information that’s available for publicly registered debt.