So you can now trade overnight. But you get no market feedback. Nevertheless, the closing price for a stock one day might well be different from its opening price the next day.
How does that all work?
My WAG is that the main trading takes place overseas. You don’t have to be in New York to trade NYSE stocks, and people in Tokyo sure as hell don’t do all their trading in the middle of the night.
As a side note: you can trade stock anytime, and if a large and/or well publicized event occurs that would shake the stock price of a certain company (say, for the hell of it, that 4 planes from the same manufacturer crash overnight), then that change will be represented in the opening price the next day, even if no significant trading occurred.
It’s like trading in the day on a market such as the NASDAQ, but the prices are much more volatile and trade volumes are exceedingly small.
You can sell, if someone somewhere wants to buy your stock at whatever price you are asking. You can also buy, providing there is someone out there willing to buy your shares at the price you set.
Here’s an article on money.com that talks a little about it.