Under Armour's stock experienced a significant pre-market decline of 13.27% on Tuesday, as investors reacted ahead of the company's scheduled earnings release.

The sportswear brand is due to post its fourth-quarter financial results today. According to earnings previews, Under Armour's fourth-quarter EPS is forecast at a loss of 7 cents, compared with a loss of 16 cents in the prior-year period, with adjusted EPS expected at a loss of 2 cents.

The pre-market plunge suggests investor apprehension regarding the upcoming earnings announcement, which serves as a key catalyst for stock price movement as market participants adjust their positions based on anticipated financial performance.