NEW YORK (Reuters) - Meme stocks are soaring again, delighting fans, frustrating detractors and showing Wall Street that the social media force behind the wild GameStop ( GME ) rally in 2021 is still going strong.

The American video game retailer is again the star, shooting up 340% over the last 10 trading days after a string of posts on the X platform from an account linked to Keith Gill, the central figure behind the previous frenzy.

Shares of other companies, including theater chain AMC headphones maker Koss ( KOSS ) and food storage container company Tupperware have followed suit. Like GameStop ( GME ), many of the stocks are heavily shorted and their fundamentals have declined over the last few years.

"It's hard not to use words like 'insane' when you look at this as a trader," said Jay Woods, chief global strategist at Freedom Capital Markets. "The first time this happened, it was more of a movement, but right now this looks like a craze where people are saying, 'Here's an opportunity' and 'Let's see if we can make a quick buck off of it.'"

Here is a quick, chart-based look at some of the factors driving the resurgence of the meme stock phenomenon.

Despite their recent stunning gains, GameStop ( GME ) and other meme stocks still have a ways to go before they match the advances in 2021. GameStop ( GME ) shares shot up as much as 1,700% that year, while AMC's surged 2,850% and U.S. listed shares of Blackberry rose nearly 280%.

Many of these companies have been the target of short sellers - investors who look to profit from selling borrowed shares betting the stock price will fall.

Short interest in GameStop ( GME ) climbed steadily this year before hitting a 20-month peak of 25% in mid-April, a couple of weeks before the shares started rallying.

That is well below the peak level of short interest in October 2020 when about 107% of the free share float for GameStop ( GME ) was sold short, exchange data shows.

The rallies have dealt short investors a heavy blow. In GameStop ( GME ) alone, year-to-date paper losses totaled $1.28 billion, estimates from ORTEX showed.

Still, there was little indication that a short squeeze - which occurs when a rising stock price forces bearish investors to unwind positions and buy back shares - is underway, said Peter Hillerberg, co-founder of ORTEX technologies.

"Calling it a squeeze may be a bit early."

Options trading has surged along with the latest meme stock rally, with much of the action concentrated in bullish call options, which profit when stock prices rise.

On Tuesday, GameStop ( GME ) options volume hit 818,843 contracts, the highest since March 2021. For AMC, 1.9 million contracts changed hands, the most in about nine months, according to Trade Alert data.

Trading data shows retail activity has picked up significantly over the last month, but is "still a far shout relative to peak meme mania days," Marco Iachini, senior vice president at Vanda Research, said in a note.

"We think retail's hand has been significant in pushing GME, AMC and other meme stocks higher Monday, and so far on Tuesday."