I think that Melbourne is now (loosely) orthodox, with some ultra-orthodox and a little bit of (remaining) reform. And it’s common here to just let the business run as normal over the weekend, with the owners dis-engaged. Same if you own shares.
When I was younger, even if your business ran over the weekend, your credit card transactions wouldn’t go through until sometime Monday anyway, but I doubt if that is the case now.
Of course, if your business is a law firm. “business as normal” over the weekend can be “closed from Friday afternoon”.
To me, there’s precious little logical difference between something coming in the mail on Saturday and someone sending an order via email or via an online platform on Saturday. As long as you don’t actually open the letter or do anything with the online order, they’re still sort of inchoate, and aren’t actually ‘real’ until you actually open that letter or view that order.
But that’s almost certainly a question for the rabbinical authorities to figure out, not some Christian guy in Texas.