DIO frÛªmiuv, Dkckmbkk 19, 1986
NEW YORK, Dec. 18ÛÓThe stock market pulled back a bit today as Wall Streeters kept a watchful eye on computer program traders.</br></br>The Dow Jones average of 30 industrials slipped 5.49 points to 1912.82, reducing its net gain so far this week to less than a point.</br></br>Volume on the New York Stock Exchange came to 155.43 million shares, compared with 148.84 million Wednesday.</br></br>For several days, investors have been warily awaiting FridayÛªs session and the quarterly ÛÏtriple witching hour,Û which marks the last trading in a series of expiring sto-ckindex futures, stock index options and options on individual stocks.</br></br>On some previous occasions, this event has produced wide swings in stock prices as professional traders closed out positions involving both futures or options and individual stocks.