What happens if it gets acquired? (My intuition would be that it should resolve NO.)

resolve No, unless it goes defunct after being acquired

So on acquisition, it doesn't resolve instantly, but you wait until end of 2028 to see if the acquirer goes defunct?

And if the acquirer continues operating but says they're shutting down the Grammarly service (usually with the promise to add Grammarly-type functionality to their own products), does that still count as "not defunct"?

I'll have to use some judgement in that case

What do you think about simply counting all acquisitions as "not defunct"? Either or both of: (a) Regardless of what happens to the acquirer and (b) regardless of what happens to the Grammarly service. Since an acquisition means a company paid money for Grammarly Inc., so by Silicon Valley logic that's a success.

Having clearly defined criteria would be useful for betting, in any case.

that's reasonable. Ill make any acquisition counts as not defunct and not bankrupt then.