The doctrine is unique to the law of the United States and apportions liability among the manufacturers according to their share of the market for the product giving rise to the plaintiff's injury.
The court responded by allowing the plaintiffs to apportion liability among the defendant drug companies according to their respective shares in the DES market.
This is particularly relevant in the pharmaceuticals context, as most plaintiffs are prescribed generic drugs and thus have no knowledge of who manufactured the product.
Jurisdictions and courts differ on the possibilities open to defendants to absolve themselves of market share liability.
Courts have declined to expand the market-share approach to asbestos (Becker v. Baron Bros.), handguns (Hamilton v. Beretta), and lead paint (Santiago v. Sherwin Williams Co.).