S&P 500, meanwhile, hovers as investors parse signals about inflation and the labor market

Meme stocks are on the move again—while the broader market is running in place.

Shares of AMC Entertainment Holdings Inc., AMC -6.68% GameStop Corp. GME -3.80% and other stocks popular with individual investors swung wildly again Friday. They have surged over the past two weeks, a frenetic rally reminiscent of the Reddit-fueled craze of late January.

AMC became the latest darling of investors who have banded together on social media in a bid to propel the shares higher. The stock dropped 0.3% Friday after surging 97% this week through Thursday. That has extended its gains for the year to about 2,300%. Its daily average trading volume this week has nearly quadrupled the 2021 average.

The S&P 500, meanwhile, has waffled in a narrow range as investors parse signals about inflation and the labor market that could feed into the Federal Reserve’s next moves. The benchmark rose 0.8% Friday after the monthly jobs report showed employers added 559,000 jobs in May, fewer than economists had projected—a snippet of evidence that could weigh against the Fed moving up its timeline for raising rates or easing back on bond purchases.

Daily volume of AMC Entertainment shares.

The S&P 500 hadn’t notched a gain or decline of more than 0.5% in the seven trading sessions through Thursday, its longest such streak since February, according to Dow Jones Market Data. It is on course for a modest 0.5% weekly gain.

Trading volumes have been tepid as well during the holiday-shortened week. About 11.9 billion New York Stock Exchange-listed and Nasdaq-listed securities have changed hands on average each day this week through Thursday, down from the 2021 average of 12.5 billion. During the height of the previous meme stock craze on Jan. 27, more than 23 billion shares and other securities changed hands.

More than 766 million shares of AMC changed hands on Wednesday alone—the stock’s second-busiest day on record, according to DJMD. That pales in comparison with the Jan. 27 peak, when 1.25 billion shares traded in a single session—but easily tops its daily average of 161.7 million shares this year.

AMC has been the third-most actively traded stock in the U.S. market in 2021, trailing only cannabis company Sundial Growers Inc. and intimate-apparel maker Naked Brand Group Ltd. , both of which are also popular with individual investors. The stocks were both up 33% this week through Thursday, on top of last week’s double-digit-percentage gains, on significantly higher-than-normal volume.

On Friday, Naked Brand dropped 7.6%, while Sundial fell 8.1%.

GameStop, the original favorite of the Reddit crowd, slipped 1.3% Friday. The stock had climbed 16% this week through Thursday, extending last week’s 26% rally. The stock, which is up more than 1,200% this year, surged as high as $483 on an intraday basis in January before falling back to Earth and hovering near $40 the following month.

Investment professionals have cautioned that the week’s hot stocks are a risky play. Even AMC agreed: In a filing Thursday with the Securities and Exchange Commission, the company said its current prices reflect market dynamics unrelated to its business—and that investors should be prepared to risk losing their money.

“The meme stock rally is not too dissimilar to a typical pump and dump, which tends to hurt a retail investor,” said Jonathan Waite, senior research analyst at Frost Investment Advisors. “These stories don’t tend to end well.”