CNN Business  — 

Amateur investors continued a frenzied runup of GameStop for the fourth session in a row, with the stock ending Tuesday up more than 92%, or about $148 a share.

After the market closed, Tesla (TSLA) CEO Elon Musk appeared to join the pile-on with a tweet that sent GameStop shares briefly above $200. His one-word comment — “Gamestonk!!” — was all it took to cheer on the the popular Reddit page that’s been generating most of the hype around the stock.

That was the second Musk tweet in 24 hours to create a stir for an individual stock — Etsy shares spiked in premarket trading Tuesday following his declaration that he “kinda” loves the online craft market.

GameStop is up more than 680% so far this year — an improbable spike led by investors congregating on the WallStreetBets subreddit. Those traders have essentially declared war on GameStop’s short sellers — investors who have placed bets that a stock would go down. The more GameStop climbs, the more money the short sellers lose.

The Reddit traders are also piling onto other struggling companies that short sellers tend to see as overvalued, including BlackBerry (BB), Bed Bath & Beyond (BBBY), Macy’s (M) and AMC (AMC).