As far as I can remember from a friend who DID get waitlisted to Stern, NYU DOES accept additional information from waitlist applicants, including new grades, although it is not necessary.
Due to Stern’s calculative planning and steady enrollment rate (~35-40%), the college tends to be very accurate in how many people to accept in order to fill up its target 610 students per class, and therefore unfortunately does not accept many people off of its waitlist.
If you were waitlisted, however, that doesn’t mean you should give up hope, because being waitlisted means that you were actually a competitive candidate. Even though they don’t accept many, they still DO accent some, and providing more information that would strengthen your application would definitely boost your ability to get an acceptance.