> Why can't I as a regular retail investor trade a stock on Saturday?
Because for you it means spending few minutes to open your app and send and order, for other market participants it means organizing holiday shifts, night shifts, and working long hours. You just cannot keep the strategies running without a human eye, the lack of oversight could be too expensive. Exchanges and banks and big players can afford that (though still, you're making some people more miserable for unclear reason), but can the small prop shop with tens of people trading on multiple exchanges do the same?
Wouldn't exchanges and market makers (i.e. the big players) be all that's needed to clear orders at reasonable spreads? Others can always choose to what scope they'd participate.
Because for you it means spending few minutes to open your app and send and order, for other market participants it means organizing holiday shifts, night shifts, and working long hours. You just cannot keep the strategies running without a human eye, the lack of oversight could be too expensive. Exchanges and banks and big players can afford that (though still, you're making some people more miserable for unclear reason), but can the small prop shop with tens of people trading on multiple exchanges do the same?