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.
So a scenario I'm curious about:
Say you're, like, an employee at DataDog, and you're involved in a long-term M&A discussion with Cisco that you know is competitive (I've had the pleasure of witnessing one of these at Arbor Networks). Things are looking great, you've picked up a bunch of strong signals that Cisco is definitely going to make a move, and then: the talks fall apart.
Knowing Cisco, you immediately reach the logical conclusion that they're about to acquire your biggest competitor.
You have no fiduciary duty to Splunk whatsoever. Cisco is, if anything, hostile. Buying Splunk options that are valuable only if Cisco acquires doesn't impact DataDog at all.
Have you violated insider trading laws if you buy the options?