> It shouldn't be problematic as long as the exchange stops trading for at least 2 out of 24 hours, since no DST shifts can bridge the gap and cause ambiguity.

> It shouldn't be problematic as long as the exchange stops trading for at least 2 out of 24 hours, since no DST shifts can bridge the gap and cause ambiguity. Actually one hour would do, but it has to coincide with New York 1am - 2am, not its own DST shift. If I remember right, only one or two exchanges had that problem in practice even though there are lots of Asian exchanges. In fact it might've been the New Zealand stock exchange rather than the Australian one. But yes all 24 hour exchanges are in trouble. This was a good 10 - 15 years ago now, so it's possible they've added a suitable hack to "solve" the problem. I work for a small consultancy now where much of the software design choices were made by me. So naturally there are no mistakes ;-)