What's going on?

So-called �meme stocks� have been front and center of investors� minds this month, and it pays more and more to know which stocks are going to the � well, you know.

What does this mean?

The meme stock craze that first kicked off in January is back again: GameStop and AMC Entertainment � two of the highest-profile winners the first time around � have now seen their stocks rise 1,500% and 2,227% respectively this year. And they�re not the only ones to have benefited from an influx of Reddit-inspired retail investors: an unprofitable Korean power plant manufacturer, a US medical insurance firm, a private prison operator, and a wrestling entertainment powerhouse have all seen their share prices make big strides.

Why should I care?

For markets: Meme stocks aren�t just fun and games.

GameStop might not have expected this opportunity to land on its lap, but it�s serious about taking full advantage now that it has: the retailer�s been using its cult following to raise cash this year, and it�s just announced a new CEO and CFO, both from Amazon. The hope is that a rejuvenated bank balance and savvy ecommerce execs at the helm will improve the fundamentals of its business, turning it from �just� a meme stock into a real heavy-hitter.

The bigger picture: Meme stocks might be running out of gas.

Meme stock hunters particularly like stocks that other investors are �shorting� � i.e. betting will fall in value. After all, those investors are likely to reverse their bets if the stock starts to rise, which just adds more fuel to the rally. But major short sellers have wised up since January, and they�re no longer so open about which positions they�re taking. That�s making it harder for meme stock hunters to find opportunities, and might kill off the meme theme as soon as it began.