Federal Reserve Chairman Jerome Powell on Wednesday said the central bank’s current trading rules are insufficient and promised that it would “make changes” after filings showed that officials traded stocks and bonds that could be influenced by its policy actions.

Powell specifically stated that Fed officials should be prohibited from purchasing assets purchased by the central bank as part of regular asset purchases or emergency liquidity measures.

The 12 Fed regional bank presidents submitted financial disclosures two weeks ago. They revealed that some of them had traded often throughout 2020 while others maintained million-dollar positions with no material change to their portfolios.

On Thursday, the Fed announced that Chairman Jerome Powell had requested a comprehensive review of ethics rules governing permissible financial activities and holdings by Fed officials.

Annual portfolio disclosures released over the past month showed that Dallas Fed President Robert Kaplan made multiple trades worth $1 million or more in 2020 in individual stocks including Apple, Amazon and Delta Air Lines.

Boston Fed President Eric Rosengren also came under scrutiny it was revealed he held financial interests in four real estate investment trusts and made several purchases and sales of similar property-owning vehicles.

He also held stock in Pfizer, Chevron and AT&T with most of his investments worth tens to hundreds of thousands of dollars.

Thomas Barkin, Richmond Fed President, reported little or no trading activity and several financial holdings exceeding $1 million.

While they form part of the Federal Reserve System as a whole, local Fed banks can be independent.

Each bank operates in a particular geographic region, has its own incorporation and board of directors. Every regional bank is required to have its own code.

Dallas Federal Reserve Bank’s Code of Conduct states that employees are prohibited from using nonpublic information other than for Bank business. Employees are prohibited from engaging in direct or indirect financial transactions based upon or in dependence on any non-public data, regardless of whether it relates to the Bank and any other individual or institution.

An employee who has access to Class I FOMC information must avoid any financial transaction that could give the impression of engaging on insider information about Federal Reserve actions and deliberations.