Standard & Poor’s Fixed Income Risk Management Services, an analytics unit that helps investors research the financial instruments in their portfolios, launched a quarterly valuation benchmarking study for residential mortgage-backed securities (RMBS), according to a corporate release. S&P will publish the third-quarter results summarizing marketplace consensus in October 2009. The agency said investors can use the tool to determine the value of their RMBS portfolios with greater transparency. Clear valuation benchmarks are based on the input of buy-side and sell-side players in the RMBS market, according to the release. The study also tracks investor expectations on variables such as house price movements, which are used to value US prime and non-conforming RMBS. Write to Jon Prior.