The group of "meme" stocks, led by videogame retailer  GameStop Corp .  (GME) that have been volatile in recent weeks as investors on a Reddit subgroup have egged each other on, were active again in premarket trade Monday.  1. GameStop shares were up 5% premarket. 2. AMC Entertainment Holdings Inc .  (AMC), the world's biggest cinema chain, were up 12%.  3. BlackBerry Ltd  (BB.T) was up 3.8%, and  4. Naked Brand Group Ltd .  (NAKD) was up 9.5%.  5. Koss Corp .  (KOSS), a maker of headphones, was up 2.9%.  GameStop  shares have gained 440% in the year to date, as investors on Reddit's WallStreetBets platform sought to punish short sellers who had driven short interest in the stock to 140% by buying the stock and creating a short squeeze. Ciara Linnane  For more from MarketWatch: http://www.marketwatch.com/newsviewer