Stock Around the Clock

All-night drugstores and supermarkets are becoming more commonplace in the U.S. these days. Another kind of commerce may also have a nocturnal glimmer: stock trading. Last week officials of both the New York Stock Exchange and the American Stock Exchange said they were taking the first look at the possibility of expanding trading hours beyond the current 10 a.m. to 4 p.m., which have prevailed for a decade.

If it happens, any such change would be phased in gradually. But the idea of stock around the clock has a logical appeal. A large share of corporate business is increasingly international, occurring at all hours of the day and night. A mere six hours of trading geared to Eastern time seems inadequate to accommodate the working hours of important industries and markets in Europe and Asia. There is also a competitive spur. Stock-trading firms that do business off the floors of the major exchanges do not keep the exchanges' hours and are attractive to big institutional investors, who do most of Wall Street's trading. Stockbrokers may not like it, though, when clients worrying about their investments in the middle of the night start calling them with buy and sell orders.