WASHINGTON — The Securities and Exchange Commission has issued a request for contract proposals to conduct the first stage of a major study comparing how the different regulatory systems that apply to broker-dealers and investment advisers affect investors.

The study was first suggested in connection with a rule that the commission adopted in April 2005, which allowed broker-dealers to offer fee-based brokerage accounts without being required to comply with the Advisers Act. The rule was the subject of a large number of comments, SEC said, but many of the concerns that commenters raised in the rulemaking, however, went well beyond the circumstances covered by the rule. The commission said the study will help it determine whether the concerns are justified and, if so, decide how best to respond. Broker-dealers are regulated under the Securities and Exchange Act of 1934. Investment advisers are regulated under the Investment Advisers Act of 1940.

The SEC's request for proposal sent out Aug. 1 follows a request for information sent in June. The RFI solicited comments on a draft RFP and sought indications of interest. The Aug. 1 RFP seeks a contractor that has a proven track record of producing "high-quality, unbiased, qualitative and quantitative research" and that is knowledgeable about the subject matter of the study, SEC said. Consulting with the commission's professional staff, the contractor would collect, categorize, and analyze empirical data from a wide variety of sources. The information studied would include marketing, sales, and delivery data about financial products, accounts, programs and services offered by broker-dealers and investment advisers to individual investors. Under the RFP, the contractor would summarize and evaluate the data for the commission's use in assessing the current legal and regulatory environment.