Analysts also pointed to the resolution of a whistleblower complaint regarding the company's accounting practices, and to aggressive cost-cutting as factors behind the toymaker's stock surge. In a statement, Mattel said it had completed an investigation into a complaint about accounting errors and would take remedial action. While the review found that income-tax expense was understated by $109 million in Q3 2017 and then overstated by $109 million in Q4 2017, "the errors were non-cash, did not affect operating income or Ebitda, and had no impact on Mattel's full-year financial results for 2017 or subsequent periods," the company said. Mattel's audit committee also decided the toymaker could keep its outside auditor, ruling the "impartiality of Mattel's outside auditor has not been impaired [and] Mattel's outside auditor can continue as its independent auditor." Jefferies analyst Stephanie Wissink called Mattel's Wednesday stock-price gains a "relief rally."