(Reuters) - The Securities and Exchange Commission (SEC) Chairman Gary Gensler said a full ban of the controversial payment for order flow (PFOF) practice is "on the table," financial newspaper Barron's reported on Monday, citing an interview.

SEC staff is reviewing the practice and could come out with proposals in the coming months, the report https://www.barrons.com/articles/sec-chairman-says-banning-payment-for-order-is-on-the-table-51630350595?mod=hp_LEAD_2 said.

Gensler has in the past been critical of the PFOF practice, whereby wholesale market makers pay broker-dealers to send them client orders which they execute on their own trading platform or a third-party platform. He has said the practice raises several conflict-of-interest questions.

The SEC did not immediately respond to a Reuters request for comment on Monday.

Shares of app-based retail brokerage Robinhood Markets Inc, which relied on PFOF for more than three-quarters of its revenue in the first quarter, closed down about 7%.

In an emailed response to Reuters, a Robinhood spokesperson pointed to its chief financial officer's earlier remarks that the company would defend its customers and ensure it does not put up barriers that keep people out.

(Reporting by Manojna Maddipatla and Sahil Shaw in Bengaluru; Editing by Aditya Soni)