Urban Haute Bourgeois was a term coined by Whit Stillman in his film Metropolitan. The term is meant to solve the problem of what to call the upper-class when the standard terms don't apply well. As Stillman put it in the film through one of his characters:

"I don't think the term 'preppie' is a very useful term. It might be
descriptive for someone still in school or college, but it's
ridiculous to have to refer to a man in his seventies.. as a
'preppie'. And none of the other terms people use - WASP,
PLU et cetera - are much use, either... that's why I prefer to
use the term 'UHB'"