The problem of investment companies selling stupidly at 3am solves itself as they either learn or go bankrupt. And the counterparties making money off those dumb moves don't need to be 'connected'.
Any overnight mispricing is going to become an arbitrage opportunity for market makers, hedge funds, and HFT firms...whom will then compete with each other to mine that arbitrage opportunity until profits go to zero, solving the market inefficiency and mispricing problem over time (and by over time, I mean like probably the first few nights and then it stops being an issue forever).
In other words, a liquidity-based mispricing that happens consistently every night is going to quickly stop being mispriced since its so predictable.
The other way to think of it is that these parties are essentially middle men who make a cut of the difference whenever someone buys/sells far from market price.
Basically if you mis price something they screw you rather than the counter party who would be interested in taking the other side at market.
I think this is stupid and does not add value, but I don't think it's harmful. It's like the stocks equivalent of a junk flipper.
In case you aren't aware, a world outside the US exists on different time zones and also invests in US capital markets.
Having 24/7 trading a massive value-add for the entire world who also invests in US companies, which benefits US companies tremendously given they will continue sucking up the world's capital.
This is yet another reason why global companies will continue going public in US markets instead of their own. Meanwhile Europe will continue struggling to form a capital markets union over the next 50 years while they slowly translate legal documents back and forth to each other in 42 languages, growing the fine dining economy of Brussels more than their domestic economies.
