A cash account (non-margin) is flat on Monday Morning. A buy & sell of the same stock is done during trading hours Monday. The account is flat again. Does the proceeds of that sale appear in your account: Tuesday before the open? Wednesday before the open? Thursday before the open? Friday before the open?
I believe it is three business days, so would be Friday before the open? (Same as Thursday after the close?)
In the U.S. T+2 went into effect in September 2017. So a trade on Monday is settled 2 business days later (normally Wednesday), so the proceeds would normally be available Thursday before the open. https://en.wikipedia.org/wiki/T+2