Mattel Faces Proxy Fight from Major Shareholder Over Potential Sale

• Southeastern Asset Management, a significant shareholder, is considering a proxy fight at Mattel.
• The activist investor has been urging Mattel to sell itself for months.
• The push for a sale comes as Mattel faces double-digit sales declines.
• Mattel has added a board member from Southeastern Asset Management.
• The proxy fight aims to nominate new directors to influence Mattel's direction.