Stock market operators Nasdaq OMX Group Inc. (NDAQ) and BATS Exchange said Thursday they will stop offering flash order types on Sept. 1 as controversy about the practice continues to build.

Direct Edge, a rival cash equities platform that has been a proponent of the practice, said it planned to maintain its current market structure, though a spokesman said it would withdraw a proposal for a new flash order type.

The Securities and Exchange Commission is considering a ban on flash order types, which give some traders a look at stock orders before they're routed out to other exchanges.

But Nasdaq OMX said in a brief statement Thursday that it won't wait for the regulator to make its move.

"We respectfully call on other markets offering similar functionality to make the same decision," the exchange operator added.

BATS, based in Kansas City, Mo., quickly followed suit with its own announcement.

Spokesman Randy Williams said in a written statement that the exchange "is pleased that Nasdaq is heeding our call to eliminate flash orders. As the first user of flash order types to call for their review, back on July 7th, we plan to back up our words by voluntarily withdrawing BOLT," BATS's version of flash orders.

The outcry against flash orders burst into public view last month after Sen. Charles Schumer, D-N.Y., told the SEC in a letter he would move to limit flash orders - which have picked up in recent months - if the commission didn't.

The flash strategy takes a stock order, after it has been checked against a market's main order book, and "flashes" it to a select group of participants, who have a fraction of a second to act on the order before it is routed to other exchanges to be filled.

The practice has helped exchanges build market share but has come under fire from critics who allege it gives some participants an unfair advantage.

Nasdaq OMX introduced flash orders in June, around the same time rival BATS Exchange implemented its own version of the practice. Both cited competitive pressures from upstart cash equities platform Direct Edge, which has used a version of flash orders to help fuel its rise to become the third-largest U.S. stock market operator.

Direct Edge, whose chief executive has defended the practice as boosting overall liquidity and improving prices for investors, said late Thursday that the Jersey City-based market operator would withdraw a proposal for a new flash order type, called "Flare," submitted to the SEC in July.

However, Direct Edge will continue running its ELP program, the model on which Nasdaq OMX and BATS based their flash strategies.

"Direct Edge supports the SEC's broad approach to the myriad issues that have been the focus of recent attention and will, of course, abide by any SEC decisions regarding this or any other matter," Direct Edge spokesman Rafi Reguer said in a statement.

NYSE Euronext (NYX), which operates the New York Stock Exchange, has been a vocal critic of flash orders, as several of its rivals have adopted some form of the trading method and have gained market share.

While the introduction of flash orders has helped boost BATS' market share, Nasdaq OMX hasn't seen much of an impact.

On a conference call discussing second-quarter earnings, Nasdaq OMX Chief Executive Bob Greifeld said Thursday that volume related to flash orders "is currently immaterial to U.S. transaction business, to Nasdaq OMX, and it will be immaterial in the future."

Nasdaq OMX has seen its share of the U.S. cash equities market slide this year, falling from 29% in January to 22% last month, though it has stabilized in recent months.

The company cited the drop in business as it reported a 31% decline in second-quarter profits Thursday.

Nasdaq OMX shares closed 1.6% higher at $22.00.

-By Kevin Kingsbury Jacob Bunge, Dow Jones Newswires; 212-416-2354; kevin.kingsbury@dowjones.com