Business Notes WALL STREET

Program trading is the habit that Wall Street loves to kick -- temporarily. Faced with angry investors and the threat of a congressional crackdown, the New York Stock Exchange last week put new limits on such computerized trading. Critics blame this practice, in which speculators simultaneously buy and sell blocks of securities, for recent stock-market gyrations. Among the Big Board's reforms: a 15-minute halt in program trading when the Dow Jones average drops 30 points, and a 30-minute delay when the index falls 75 points.

The exchange unveiled its policy after most major Wall Street firms had backed away from program trading. But skeptics noted that brokerages had scrapped program trading following the 1987 crash, then resumed the lucrative practice as soon as the market became less volatile.