A former Fidelity Investments vice president, Leslie Seff, said that because of the way markets are structured today, initial public offerings are thwarted. He also said the markets have come to rely too much on high-frequency trading. As a remedy, Seff said, the Securities and Exchange Commission should repeal Reg NMS, which requires dealers to complete every equity order at a given price anywhere in the marketplace, even if that price is marginally higher than a big order awaiting fulfillment.