10 Stocks Already Shocking 2026 With Massive Gains

8. Under Armour Inc. (NYSE:UA)

Under Armour grew its share prices by 14.44 percent week-on-week to climb to a new four-month high, as investors mirrored a significant investor’s hike of its stake in the company.

The rally followed a regulatory filing last week that Canada-based financial services firm, Fairfax Holdings—already a 10 percent owner of the company—had increased its stake in the sports apparel maker through a series of buying activities on December 30.

During the period, Fairfax said that it acquired $67 million worth of additional shares in Under Armour Inc. (NYSE:UA), covering more than 11.5 million Class A and 1.67 million Class C shares at an average price of $5.1408 and $4.9474, respectively.

The transactions followed a separate round of acquisition on December 22 to 29, where Fairfax Holdings also bought an additional 15.68 million Class A and C common shares at average prices of $4.6133 and $4.4055, respectively.

Under Armour Inc. (NYSE:UA) is one of the leading makers and distributors of athletic performance apparel, footwear, and accessories globally. In the second quarter of fiscal year 2026, ending September 2025, Under Armour Inc. (NYSE:UA) swung to a net loss of $18.8 million from a $170.38 million net income in the same period last year.

Revenues dropped by 5 percent to $1.33 billion from $1.40 billion year-on-year, dragged by lower revenues from the North American business, wholesale, and apparel.