Must be authorized by the Greenlandic government and be widely recognized; U.S. invasion followed by a sham referendum wouldn't count.
1,000I'm not sure what the US invasion aspect of this market is about, but according to this article, holding a referendum seems entirely plausible
https://www.theguardian.com/world/live/2025/feb/07/greenland-independence-referendum-denmark-snap-election-sweden-belgium-europe-latest-updates-news
Greenlanders could soon vote in a referendum on independence from Denmark under plans proposed by the ruling party, Siumut (9:21). Party leaders want to accelerate the independence process by triggering Section 21 of the Greenland Self-Government Act to negotiate the terms of a future relationship and hold an independence referendum within the next parliament. The promise comes just weeks before a snap election on 11 March and after growing pressure from US president Donald Trump, who expressed his interest in Greenland.