Earlier quoted context omitted.
This is great, and as good a place as any for the thread to sprawl from, so I'll ask: it depends on how you know the stock is going to shoot up the next day, right? Trading on private information isn't illegal, and there's a huge variety of ways to acquire private information at varying levels of confidence, and in a sense the purpose of the markets is to aggregate everyone's private information to estimate a price.…
That practice has been referred to recently as "shadow (insider) trading". It's an actively evolving area of case law, but the SEC's opinion is yes, see https://wp.nyu.edu/compliance_enforcement/2022/01/19/sec-v-p... Or Matt Levine on the same case: https://archive.ph/5Dlmw
In my hypo and his, the origin of the private information I've acquired is still business my employer has conducted, so there's a better-than-baseline probability that the SEC would see this as misappropriation --- even if my employer wasn't directly going to trade on this, or if it was hard to trace any harm to my employer, it's still potentially not OK for me to profit from it.