You'll find that even on some fairly large names there isn't all that much activity during the day. There's a lot of names, and there's a lot of trading in the

You'll find that even on some fairly large names there isn't all that much activity during the day. There's a lot of names, and there's a lot of trading in the auctions, so the total volume in the market won't result in a steady flow for a particular share. My guess is it will stick out like a sore thumb if you buy x shares right before an announcement and sell x right after. Especially if you do nothing else. Pretty much as soon as you've exited a second announcement-trade red lights should be flashing.