Back in early November, Google's John Mueller implied you may be more likely to get featured snippets if you use structured markup on those pages. Then shortly after, Gary Illyes from Google said Google does not use structured markup for featured snippets.
So which is it? Well, they don't use structured markup for featured snippets.
John Mueller from Google said yesterday on Twitter that Google doesn't use structured markup for featured snippets.
@realSEyOda Do you mean featured snippets? We don't use markup for that.
— John Mueller (@JohnMu) June 21, 2016
So I guess there you go.
Forum discussion at Twitter.