>after-hours aren't going through the "markets", but through Electronic Communication Networks (ECNs) I wasn't aware of all the differences, but I think anothe

>after-hours aren't going through the "markets", but through Electronic Communication Networks (ECNs) I wasn't aware of all the differences, but I think another more abstract answer to the question of "why not 24/7" is that the whole point of a "market" is to bring people together to trade, and 24/7 would reduce liquidity. I remember reading that volume is very much not evenly distributed through the day so one might ask why not reduce the hours instead, have like an hour to trade in the morning and an hour in the afternoon...