Signage stands in a GameStop Corp. store in Peru, Illinois.

GameStop shares tumbled 9 percent on Friday, after the video game and electronics retailer said sales in its established stores plunged 18.7 percent in November and December.

Plagued by heavy promotions, soft store traffic, and double-digit sales declines in hardware and video games, the chain's overall sales fell 16.4 percent to $2.5 billion.