Kate and Laura Mulleavy of fashion label Rodarte created some of the most beautiful costumes of the year for Black Swan. However, due to a couple of factors, should the film get nominated for, or even win, an Oscar for costuming, they will not be the ones gaining the recognition.
The first reason is that in negotiating with the film-makers, they did not negotiate a credit for their work. That credit goes to Amy Westcott, who is the person named in the credits. Additionally, at the time the film was made, the sisters were not members of the Costume Designers Guild, which I guess is a requirement for nomination.
While they haven't technically been screwed out of a potential nomination or win, it's unfortunate that a couple of oversights mean they may not get the full recognition they deserve. I can only hope that, should the film win, Westcott gives credit where credit is due in her speech.