On both Thursday and Friday this week (8/3 & 8/4), near the end of the day, the Nasd comp chart turned decidedly north . I was not expecting this, especially on friday. was this program buying? or was it general buying pressure? I have noticed moves like this before, often in the last 30 or 40 minutes of trading. sometimes in the last 5 minutes or so. a couple of times i have seen the chart move north in an almost vertical line for a few minutes, even more obvious than the two examples this Thur and Fri how can you know when program trading is in gear? and if/when you identify program trading, are there are clues to tell when it has stopped?