(Reuters) – Friday’s Federal Reserve decision to restrict trading of policymakers, senior Fed employees and policymakers was taken after an ethics investigation that engulfed Fed policymakers. The scandal threatened to shake the confidence in central banks integrity.

The Fed said the rules are meant “to ensure public confidence in the impartiality and integrity of the Committee’s work.”

Some of the rules were revealed last October. The Fed’s top officials cannot purchase stocks or sector funds and are prohibited from holding individual bonds, agency backed securities, cryptocurrencies, commodities, or foreign currencies.

Short sales, derivatives and the purchase of securities on margin are all prohibited. Officials will need to provide 45-day notice, obtain approval, and give prior notification for every transaction. The rules state that all investments should be kept for at least one year.

The Fed’s trading restrictions are set to go into effect May 1, with most of its new trading restrictions in place by July 1. Pre-clearance rules and advance notice rules will be in effect from July 1 through the end. According to the central bank, current Fed officials will need 12 months for compliance. New staff members and policymakers have six months.

Following reports that Eric Rosengren of Boston Fed and Robert Kaplan of Dallas Fed had been active traders in 2020, the Fed established the rules. The central bank also launched an extensive effort to counter the devastating economic consequences of the COVID-19 Pandemic. The Fed’s actions helped to boost financial markets.

Richard Clarida was also criticized for his correction of a financial disclosure from December that showed he sold a stock portfolio and then quickly bought it again shortly before the Fed declared a barrage rescue programs to stop the economic downturn caused by the pandemic.

However, questions remain about how much back and forth may have occurred over policymakers’ personal trading in a year when markets first cratered, then rebounded on the basis of both massive federal fiscal stimulus and an aggressive rescue effort by the Fed.

Responding to a Freedom of Information Act Request by Reuters last week, Fed stated that there were approximately 60 pages of correspondence between Fed’s ethics officers and policymakers about financial transactions during 2020. However, it “denied in complete” to release these documents, citing exemptions to the information act.

Although the limits to trading have been lifted, at most one lawmaker called for an investigation by the Securities and Exchange Commission into the trading activity of Fed officials in order to find out if they violated any insider trading regulations.