Thanks to Hurricane Gloria, Jefferies Group Inc. mopped up big profits yesterday.

The Los Angeles-based brokerage firm took advantage of its status as a non-member of the New York Stock Exchange and continued to swap stock all day, even though all other exchanges were closed because of Hurricane Gloria and the threat it posed to Wall Street.

While other brokerage houses that are members of the exchange were barred from making trades of exchange-listed stock, Jefferies traded more than 12 million shares -- about twice its daily average volume.

Although that was a fraction of the 106 million shares traded on an average day on the New York Stock Exchange, "it was a good day" for Jefferies, said Frank Baxter, managing director of the firm's London office. Baxter, who was answering calls placed to company chairman Boyd L. Jefferies, was in Atlanta with other company executives attending a board meeting.

"We can trade wherever we are," Baxter said. "We are happy to be of service to our clientele in face of adversity. . . . We are happy to be of service for a reasonable profit."

"Jefferies is notorious for trading when no one can or will," said a Washington financial analyst who continued working -- but not making trades -- yesterday.

New York brokerage houses shut down after a majority of big brokerage houses, concerned about the hurricane, asked the New York Stock Exchange to close. Other regional exchanges remained opened for a short time and then closed, as did the over-the-counter market run by the National Association of Security Dealers.

Market traders at several major New York firms could not be reached by telephone. A spokesman for Salomon Brothers, in a building in mid-Manhattan, said, "there was nary a soul in the building. They have all disappeared."

Jefferies has been controversial in the financial industry for not playing by the exchange's rules. By not being a member of the New York Stock Exchange, the 22-year-old brokerage house can trade stock at all hours, including evenings, weekends and holidays, whenever there is action.

Jefferies also makes deals on stock halted by the NYSE, pending major news announcements.

Chairman Jefferies once noted that "these periods are becoming an important part of our business; they've brought us lots of recognition and new customers. . . . We believe professional investors should be able to buy or sell a security whenever they wish."

These periods also prove very profitable to Jefferies, which last year earned nearly $12 million on revenues of $107 million. The bulk of that revenue was from commissions from trades.

Jefferies makes these third-market trades by matching buyers and sellers. Or, if necessary, the firm will first buy shares from willing buyers for its own account to have inventory to sell to future buyers.

Yesterday, "almost all crossing was between professional investors -- buyers and sellers," Baxter said. "We did facilitate some trades" with the firm's inventory, Baxter added. Baxter declined to say whether some of the trades were for brokerage houses that were members of the exchange, saying only, "we have done a lot of business with brokers."

Much of yesterday's business was due to the trading of more than 5 million shares of General Foods Corp., which received a takeover bid from Philip Morris Inc. of $120 a share. On Thursday, General Foods stock closed at $110.25. On Jefferies' trades yesterday, the stock closed at $118 a share.

Baxter said that other food stocks were strong, "in sympathy" with the General Foods acquisition. Oil stocks also were strong, with the renewed threat by Iran to close the Strait of Hormuz, while airline stocks were weak in light of the threat of higher aviation fuel prices.

Insurance stocks, as a result of Hurricane Gloria, were lower, Jefferies said.

As is its custom, Jefferies continued to trade into the evening. "We never close," said Baxter. But he said most of the trades had already been completed for the day.