Three major Wall Street firms, Morgan Stanley & Co., Bear Stearns & Co. and Deutsche Bank Securities Inc., agreed Tuesday to pay $15.63 million to settle allegations that they accepted unusually large trading commissions from clients who received shares of hot new stocks.

NASD, the industry regulator formerly known as the National Association of Securities Dealers, sanctioned all three firms for failing to "comport with high standards of commercial honor" and required them to return all of the commission money and to pay an additional 10 percent fine. The investigation found that some institutional customers, mostly small hedge funds, paid stock trade commissions of $1 to $3 per share on the day right before or right after they received allocations of stock in sought-after initial public offerings (IPOs). Normal commissions average about 6 cents a share.

The settlements are part of NASD's long-standing probe into the way IPOs were handed out during the technology bubble of the late 1990s. At that time, the share price of many IPOs shot up dramatically during the first days of trading, netting huge profit for anyone who was able to buy at the offering price.

Since 2002, several banks, most notably Credit Suisse First Boston, have made much larger payments to settle allegations that they accepted kickbacks from customers who profited from IPO allocations. CSFB paid $100 million, and former CSFB investment banker Frank P. Quattrone was convicted earlier this month of obstructing a grand jury investigation into the same practice.

Tuesday's settlement did not allege that the three firms improperly shared in clients' profit or explicitly demanded the commissions in exchange for the IPO allocations. Rather, the regulators said Morgan, Bear Stearns and Deutsche Bank officials had a duty to return higher-than-normal commissions because their brokers had not done anything special to earn them.

"Firms can't just accept those commissions and say thank you very much. You can't share in customers' profits," said NASD executive vice president for enforcement Barry R. Goldsmith. These settlements, which come at a time when the IPO market is picking up, "are a reminder . . . that we will make the process fairer and more equitable."

Unlike retail customers, who have little bargaining power over the commissions they are charged, large investors generally tell the broker what they are willing to pay per share, industry officials said. In these cases, hedge funds that received IPO shares would offer the broker rates far above average for officially unrelated trades. The $5.39 million Morgan settlement cited an example of a customer who received 1,000 IPO shares in WebMethods Inc., which rose from $35 per share to $212.625 on the first day of trading -- a one-day paper profit of $177,625. On that same day, the customer paid a $3-per-share commission for 20,000 shares of Tiffany & Co., a commonly traded stock.

The settlements cited internal e-mails that discussed commissions and IPO allocations, but unlike e-mails in some earlier IPO cases, these did not spell out a clear quid pro quo. One Bear Stearns broker wrote that a customer was "Paying $1 per today on 150,000 shares[.] Happy with [hot IPO] allocation of 25,000," according to the e-mail as edited by NASD. And a Deutsche Bank broker wrote that a customer called Dave "thanks you for the Foundry allocation. . . . He is Giving us a $1.00 commission on a hundred thousand shares this morning."

Spokesmen for all three firms would comment only briefly about the settlements, saying in essence they were happy the matter was behind them. "We are pleased to have reached a voluntary resolution with the NASD," said Rohini Pragasam, spokeswoman for Deutsche Bank, which paid $5.29 million. Bear Stearns paid $4.95 million.