I think it's less about being factually wrong, and more about leading people to factually wrong conclusions with truthful statements.
Even just saying "X sells stock Y before event Z" imples that X knew about event Z and that it would affect the stock price of Y. People will read headlines like this and walk away assuming there was insider trading, but that may not be the case. Nothing in that example headline has to be false in order for it to spread falsehoods.
A lot of this type of misleading rhetoric often boils down to simply exploiting that many humans mistake correlation for causation and our education system really hasn’t don’t enough to hammer in not confusing those two.
Sure, that's a common technique, but would you really call it misinformation? I would call it misleading. Otherwise most of the financial press is misinformation and the word becomes kind of meaningless.
Even just saying "X sells stock Y before event Z" imples that X knew about event Z and that it would affect the stock price of Y. People will read headlines like this and walk away assuming there was insider trading, but that may not be the case. Nothing in that example headline has to be false in order for it to spread falsehoods.