House Rosznar earns much of its wealth in the real estate and winemaking businesses. Historically, the family was convicted of slave trading—highly illegal in Waterdeep—and banished over a hundred years ago, but has since returned.
The Rosznars' inability to regain the respect they feel they deserve rankles them. The slave trade has continued in Amn and elsewhere, and it's not like other noble houses don't have skeletons in their closets. But just because of a little family squabble that went public, the Rosznar name has been said with a sneer for a century.