Business Notes SECURITIES /

The New York Stock Exchange has not exactly stampeded toward a longer working day. In 1952 the Big Board extended the closing time 30 minutes, to 3:30 p.m., and in 1974 to 4 p.m. In 1985 the exchange moved the opening bell up 30 minutes, to 9:30 a.m. But exchanges in Europe and Japan trade N.Y.S.E. stocks when the Big Board is closed, typically handling an amount equivalent to 9% of the exchange's daily business. Now the Big Board is getting in gear. Last week chairman John Phelan unveiled a plan to move the N.Y.S.E. to 24-hour trading by the end of the decade. "There is some volume going overseas, and we'd like to capture some of that volume back," he said. The transition will begin later this year with 15- to 45-min. after-hours trading sessions that will be handled by computers. Next year the Big Board plans to have stock auctions at 8 p.m., midnight and 5 a.m., with each stock trading at a single price.