GameStop has seen its stock tumble by 16 percent after it notified investors of a 25.7 percent drop in holiday sales. 

Although the company said it "expected a challenging sales environment over the holiday season," it conceded its performance was "well below" expectations. 

That sales decline was reflected in the retailer’s stock market performance, and GameStop’s stock price is now down 24.5 percent from the start of the year. 

The company's showing during the holiday season was so below par that GameStop has revised its fiscal outlook for 2019, and now expects to see an overall sales decline of up to 21 percent -- previously it has anticipated "a decline in the high teens."