IMO you don't need to be particularly careful to avoid insider trading if you were never at risk of doing it. It's pretty obvious when you have a duty of confidentiality and when you don't (again, in the US). The hypothetical scenario upthread just doesn't have any of the elements.

> As an example, if you were an employee of a listed company (not such an unlikely scenario given the capital requirements to pull this off) that was about to engage in the proposed scheme (publishing pro-adblock adverts) and it wasn't yet publicly known (which would be necessary if you want the scheme to be fully effective), and you shorted Google shares, you could easily fall foul of insider trading.

Yeah, that isn't the scenario described earlier at all. Here's what was proposed:

> I wonder if you could spend a few million on promoting adblockers to justify a short position on Google or Meta.

In this sentence, the entity performing the short and performing the advertising are one and the same.

Realistically, the vast majority of people don't have a "few million" lying around that they can just casually risk on a huge gamble like this. It's likely you have at least several tens of millions but more likely hundreds of millions before the risk/reward would even come close to making sense (because you wouldn't want to commit most of your resources). The most plausible scenario is therefore something like a hedge fund.

You're reading "you" to mean the reader (highly implausible), I'm reading it as the generic/impersonal "you" (as in "one could spend...").

So sure, there are a tiny percentage of people who might consider doing this themselves and they don't need to worry about insider trading (although we're still pretty close to market manipulation where the sole purpose of the adverts is to crash the share price and profit from that). A much larger percentage of people who might consider such a thing would need to at least examine whether they might trigger insider trading laws.

Blanket statements don't work here.