It’s officially kaput based on word from Dan Akroyd according to SciFi Wire.

Apparently Bill Murray, who owns 1/5 of the license rights, just doesn’t want to do it. After GB2, I can’t really blame him, but a quick scan of Murray’s filmography in IMDB shows that the last hot thing that had his name on it was 1993’s Groundhog’s Day (ironically written & directed by GB co-scribe Harold Ramis). Maybe you’re being a bit too picky Bill?