Consumer groups say the issue has already been examined, most recently in 2008, when the Securities and Exchange Commission asked the RAND Corporation, a nonprofit organization, to study the business practices of broker-dealers and investment advisers.
It immediately initiated an investigation of the compliance and supervisory practices of broker-dealers, mutual funds and hedge funds to vet how they prevent the spread of false rumors.
They argue that there is a distinction to be made between the broad practice of brokers' asking an investor about his intention to buy stock in the aftermarket in the interest of price stability, and brokers' securing firm agreements to buy as a way to add fuel to a speculative stock.
Mr. Courson acknowledged, however, that lenders have had concerns about the business practices of some brokers, and that the pressure on brokers could continue.
The administration, economists said, did little to curb the practices of mortgage brokers, who are regulated by the states.
Last year, some members of Congress opened inquiries into the business practices of data brokers in light of an investigation by The New York Times.
That problem prompted the Federal Trade Commission in a report last year to recommend that Congress enact legislation "to provide greater transparency for, and control over, the practices of information brokers".
The S.E.C. began the first of the act's required studies on Tuesday, asking investors for feedback on whether the practices of stock brokers and investment advisers should continue to be subject to different regulatory standards.
One issue the campaign is not designed to address, however, is a recommendation from the F.T.C. earlier this year that the industry set up a public Web portal where consumers could learn about the practices of data brokers and about consumer choices for accessing or deleting information collected about them.
"I think we were astounded by the amount of data that's held by all of these agencies — not just social media companies but data companies like Cambridge Analytica; political parties the extent of their data; the practices of data brokers," she said.
