Under Armour Inc. (UAA) shares rallied Tuesday afternoon after fresh SEC filings revealed that longtime value investor Fairfax Financial Holdings went on a buying spree, scooping up millions of shares at what appears to be bargain prices.

A Big Bet Near the Bottom

The numbers tell the story. A Form 4 filing from late Monday shows Fairfax purchased a total of 15.68 million Under Armour shares across both the Class A and Class C lines between Dec. 22 and Dec. 29. The weighted average price? About $4.53 per share. That lifted Fairfax's total stake to 30.45 million Class A shares and 7.78 million Class C shares.

An amended Schedule 13G filed for the same period puts Fairfax's beneficial ownership at 16.1% of Under Armour's Class A float. Compare that to the Form 3 filed Dec. 22, which listed 19.31 million Class A and 3.24 million Class C shares, and you can see Fairfax increased its Class A position by nearly 60% and more than doubled its Class C stake in just over a week.

Here's why that matters: the stock had been trading near its 52-week low of $4.13. Fairfax wasn't bottom-fishing with pocket change. They bought aggressively, paying roughly a 10% premium to those lows, which traders are reading as a strong vote of confidence from a new 10%-plus insider with board representation.

What Large Insider Buys Signal

When a heavyweight investor loads up on shares in such a concentrated fashion, market participants take notice. Large, above-market accumulation often signals two things: the buyer sees the stock as undervalued, and they may have plans for strategic or governance changes down the road. There's also a technical angle. Absorbing this many shares can tighten available supply, which helps explain why the stock popped Tuesday.

The Turnaround Story

Under Armour has been in rebuilding mode. In November, the company reported second-quarter adjusted EPS of 4 cents versus the 2 cents analysts expected. Gross margin came in at 47.3%, down 250 basis points year-over-year but still ahead of consensus estimates. Management guided fiscal 2026 revenue down 4% to 5% and adjusted EPS to just 3 to 5 cents, citing soft demand and tariff headwinds.

Days later, Under Armour expanded its fiscal 2025 restructuring plan, adding $95 million in charges tied to separating the Curry Brand and other actions. But the company also raised its fiscal 2026 adjusted operating-income outlook to $95 million to $110 million, suggesting management sees a path forward despite the near-term challenges.

Fairfax's latest buying spree suggests at least one heavyweight investor believes that turnaround plan will ultimately pay off.

The Valuation Picture

According to stock rankings, Under Armour shows a Value score of 59.22, while its Momentum score sits at just 4.22. The stock has a positive short-term price trend but negative medium and long-term trends, highlighting that this is very much a valuation-driven setup rather than a momentum play. Translation: it's cheap, not hot.

UAA Price Action: Under Armour shares were up 6.07% at $5.07 at the time of publication Tuesday, according to market data.