The GameStop short squeeze occurred primarily in January 2021. It started with retail investors from online platforms like Reddit's r/wallstreetbets buying GameStop (GME) stock, recognizing that it was heavily shorted by hedge funds. This buying frenzy drove up the stock's price, triggering a short squeeze where short sellers had to purchase shares to cover their positions, further escalating the price. The peak of the squeeze happened towards the end of January, resulting in significant media attention and discussions about market dynamics and retail investor influence.