July 15 (Bloomberg) — The U.S. Securities and Exchange Commission should act immediately to eliminate two stock market pricing models that create conflicts of interest for brokers, Senator Carl Levin said in a letter to SEC Chair Mary Jo White.

Levin, a Michigan Democrat, criticized systems used by exchanges such as Nasdaq OMX Group Inc. and wholesalers such as Citadel Securities that pay brokers for sending orders to be filled. Intercontinental Exchange Inc. Chief Executive Officer Jeff Sprecher and IEX Group CEO Brad Katsuyama also have called for regulators to ban maker-taker, a system in which rebates are paid to brokers who provide exchanges with liquidity.

"Eliminating maker-taker pricing would improve confidence in U.S. equity markets," Levin, a Michigan Democrat, wrote in the letter released today. "Such action also would reassure investors that they can rely on their brokers to provide best execution of their trades, without having to question whether a broker might instead be seeking to maximize its own profits at the customer's expense."