Stockbrokers routinely succeeded in erasing settlements of customer complaints from their regulatory records in the wake of 2008’s market turmoil, making it harder for investors to research the money managers, a group of plaintiffs lawyers said.

Brokers who resolved arbitration cases and asked for the records to be cleared were granted expungement 97% of the time from May 2009 through 2011, according to a study released today by the Public Investors Arbitration Bar Association, a group of lawyers who represent investors in disputes with U.S. brokers. One person was allowed to erase 35 cases, according to the report, which examined 483 settlements in the period.

“Investors who are diligent enough to seek out information about brokers may be getting a woefully incomplete picture,” Scott Ilgenfritz, the president of the group and author of the study, said in a statement. “Regulators need to step in and crack down on the granting of expungements.”

Firms require their investor clients to agree to resolve disputes through arbitration, rather than in court. The results are posted on the website of Finra, the industry-funded regulator that coordinates the forums. The arbitrators who decide the cases are supposed to allow brokers to clear their records only of false claims, according to Finra’s website.

Finra said today in a statement that it shares the lawyers’ concerns and is considering changing its rules regarding conditions on settlements. The group told arbitrators this month that they should ask whether settlements are conditioned on expungement and make sure brokers provide evidence supporting their innocence, said Michelle Ong, a spokeswoman.

The regulator said in the statement that it removed 838 complaints from brokers’ records from 2007 to 2011, which amounts to 5% of the 17,765 disputes filed in the period.