N.Y. Brokerage Offers Money-Back Guarantee : *Securities: The plan does not cover unhappiness about stock prices. Other firms call the idea a gimmick.

In an effort to lure customers from other stock brokerages, discounter Quick & Reilly Inc. on Friday said it would refund commissions to any investor unhappy with service on a trade.

The New York-based brokerage said it would refund commissions to any investor who complained about poor service within 45 days of a trade. The money-back guarantee--believed to be an industry first--doesn’t apply to unhappiness over stock prices or other conditions outside the firm’s control.

“In today’s world, people want service,” said Thomas C. Quick, president of the brokerage. “We offer service and we’re willing to put our money where our mouth is.”

But Quick & Reilly’s leading competitors chided the guarantee as a gimmick, saying there is little room for error in trade executions.

“It’s really hard to give poor service when making a trade,” said Larry Armstrong, executive vice president of Boston-based Fidelity Brokerage Services Inc. “It looks like a gimmick to me.”

Quick & Reilly is offering the guarantee as part of an overall plan to attract new customers at a time when individual investors, dissatisfied with returns on bank deposits, are charging into the stock market. The nation’s brokerages are competing intensely for new investment dollars that are pushing some aspects of the business to new heights.

Quick & Reilly said new accounts opened during the first 10 days of March were double those of the same period a year ago. The quarter that ended on Feb. 28 was its strongest ever, Thomas Quick said.

He said the firm later this year plans to offer 24-hour trading and investments in no-load mutual funds to better compete against the nation’s leading discounter, San Francisco-based Charles Schwab Corp. Schwab spokesman Hugo Quakenbush said it was doubtful that the firm would match Quick & Reilly’s guarantee.

“You don’t expect a guarantee when you buy a Rolls Royce,” he said.

Scott W. McAdams of the Seattle-based brokerage Ragen MacKenzie Inc. said the guarantee would enhance Quick & Reilly’s “image of providing personal service.” McAdams said that Quick & Reilly, unlike its competitors, matches a customer with a broker who handles all that customer’s trades. “They portray themselves as personal service-oriented,” McAdams said. “This is a step in that strategy.”