Under Armour CEO Kevin Plank is planning to sell more than a million shares of his company for estate planning and charitable giving purposes, according to a Securities & Exchange filing.

Plank plans to sell up to 1.13 million personal Class B shares over a
period of approximately ten months beginning in February 2011, as well up to125,000 shares of the company's Class B stock for his charitable organization.

Plank owns 12.5 million shares of the company's Class B stock, or about 24.5% of the total shares of Class A and B shares available as of Oct.
31. He owns 76.5% of voting stock.

If Plank completes all the planned sales under this trading plan, he would beneficially own 11.25 million shares of Class B Common Stock, representing approximately 22.1% of the total shares of Class A and Class B Common Stock outstanding as of Oct. 31, 2010 and approximately 73.9% of the voting power of all shares of Class A and Class B Common Stock outstanding as of October 31, 2010.