Market-Makers Now Posting Execution Data Online brokers likely to show trade stats in investor-friendly formats.(MAKING MONEY IN MUTUALS)(INVESTMENT TRENDS)

Byline: Paul Katzeff

Put your sunglasses on. Another shade is being raised on the shadowy world of trade execution.

To give investors a clearer look at back-room trading efficiencies, so-called market centers on Tuesday began to post execution data for listed securities on the Web. This is a step toward answering investor beefs about order routing, which often works for brokers and against investors.

"Buying order flow is done in a number of ways," said Stephen Williams, senior special adviser to the Securities and Exchange Commission. "They (can) create conflict of interest between brokers and brokerage customers. We're not forbidding that. But we're saying that those conflicts of interest have to be disclosed."

Potential conflicts lie in payments that brokers often get for funneling orders through a market center. Investors can be hurt when a brokerage picks a market center based on payment for order flow, rather than on whether a center will get the best price or execute trades the fastest.

Market centers started with the 2,000 stocks having the heaviest trading volume on the NYSE and the 400 most popular on the Amex during a phase-in period, the SEC said. Market centers must post Nasdaq national market securities by Sept. 30.

Market centers include market-makers, specialists and electronic communications networks, or ECNs. These firms conduct trades on the national and regional exchanges for investors large and small.