After Stiefel Laboratories Inc. was acquired by GlaxoSmithKline for $3.6 billion in 2009, four Stiefel employees sued, insisting the common stock they held in Stiefel had been undervalued in a stock buyback and they had suffered financial losses.

The four filed a derivative action under the Employee Retirement Income Security Act of 1974, which protects the interests of employee benefit plan participants and their beneficiaries.