Under Armour's CEO Used To Send Phil Knight Christmas Cards - Now He Refuses To Even Say The Word 'Nike'

One of the most interesting parts of the New Yorker's recent profile of Under Armour founder Kevin Plank is reporter Kelefa Sanneh's description of his company's growing rivalry with Nike in the sportswear market.

Plank refuses to say the word "Nike" anymore, apparently.

Though Under Armour's revenues are about one-tenth the size of Nike's, Plank is targeting the industry leader on several fronts. Under Armour recently opened a new office in Portland, Ore., a short drive away from Nike's Beaverton headquarters.

Plank has also told his executives to focus on selling more women's sportswear, a category Nike has owned since making it a priority in the early 2000s.

And Under Armour is also planning to challenge Nike's dominance of the sneaker world with a new shoe called the Speedform Apollo, which is marketed as having the comfort and fit of Under Armour's famous compression shirts because it is manufactured entirely in a clothing factory.

Sanneh reveals that in the early days of Under Armour, founded in 1996, Plank would send Nike chairman Phil Knight a Christmas card every year, telling him to watch out for Under Armour.

But now that Under Armour has grown to a nearly $13 billion company, the rivalry has become so real that Plank refuses to acknowledge Nike by name. Instead, he refers to Nike only as "the guys out West."

For more on Under Armour, including the company's strategy for reaching women and its response to the alleged failure of its speedskating suits at the Sochi Olympics, you can read Sanneh's complete story here.