GameStop and AMC’s share prices roared back on Friday rising by 68% percent and 53%, after crashing to earth a day earlier when brokerages reined in trading. The firms’ shares closed the week with massive gains of 400% and 278% respectively.

The resurgence came after brokers, notably upstart Robinhood, reversed course and allowed buys of GameStop and other heavily shorted shares to restart on Friday.

The trend left many market professionals worried.

“A lot of people today again engaged in buying the latest shiny object,” said Doug Kass, a money manager and founder of Seabreeze Partners in Palm Beach, Fla. “This does highlight the lack of regulatory intervention.”

The continuing volatility was a reaffirmation that populism is on the rise among at-home investors who are brandishing digital pitchforks at hedge fund titans and other perceived enemies on Wall Street. It was such individual players conversing on Reddit who banded together to drive up shares of GameStop and other firms in a bid to hurt big investors who were betting on their decline.

The turmoil has led many to pick sides. Leon Cooperman, the founder of Omega Advisors, spoke scathingly of the “Robinhood market,” referring to the no-fee stock-trading app and its largely novice clientele. He called the rise in GameStop and other targeted stocks a “loser game” played by people who “don’t have any idea what they’re doing.”

”I’m not damning them,” Cooperman said on CNBC Thursday. “I’m just saying from my experience, this will end in tears.”

Meanwhile, former Daily Show host Jon Stewart spoke out for the insurgents.

”The Redditors aren’t cheating, they’re joining a party Wall Street insiders have been enjoying for years,” Stewart posted Thursday on Twitter. “Don’t shut them down ... maybe sue them for copyright infringement instead!!”

Indeed, with anger still simmering at the decision of Robinhood and others to limit trading, the U.S. Securities and Exchange Commission said Friday that it would scrutinize the brokerages’ decisions to halt buying.

At the same time, however, the agency, under pressure to calm an unsettled market, warned traders about engaging in illegal schemes to drive up stock prices.

The SEC said it was working with other regulators and stock exchanges to “identify and pursue potential wrongdoing,” according to a statement from acting chair Allison Herren Lee and the agency’s commissioners.

Lyn Alden Schwartzer, who operates an investment research firm in Atlantic City, said America’s widening wealth gap, bailouts for corporations, the COVID-19 pandemic, and mass unemployment have all stirred deep resentment. She predicts a long run for populist events like this Reddit rebellion, perhaps for the rest of this decade.

Populism has blossomed on social media and in social movements on the streets. At its most extreme, the unrest has helped prop up QAnon on the right, and protesters on the left, all part of a trend punctuated by the Jan. 6 storming of the U.S. Capitol by pro-Trumpers.

Now GameStop, AMC, and other heavily “shorted” stocks sit squarely in the sights of home-bound rebels armed with trading software.

The gathering place for many was an online chat forum hosted by Reddit under the community WallStreetBets. There, participants focused on stocks that were being heavily “shorted” — in which investors sell a borrowed stock, betting it will fall in value so they can buy it back later for less money, resolving their borrowing and pocketing the difference. Short sellers can profit dramatically from a target stock falling in value.

Hedge funds wagered billions on this strategy in GameStop.

“They find a declining business line, for instance a brick-and-mortar store that relies on selling hard copies of video games that can now be downloaded from home, and realize the business could go bust in a few years. When buying the stock back later at a lower price, massive gains can be had,” wrote James Vogt with Tower Bridge Advisors in Conshohocken, in a note to clients.

But WallStreetBets investors noticed the massive short position and found a way to exploit it by driving the price upward. When a hedge fund’s short doesn’t pan out and a stock climbs, rather than falls, even a 10% move upward can generate billion-dollar losses. In GameStop’s case, many hedge funds were forced to prematurely buy back the shorted stock — spending cash to do it — or risk massive losses or even going bankrupt. This only further fueled the stock’s climb.

“This game has been around forever, but is certainly exacerbated by the internet,” Vogt said. Normal market moves, Vogt said, would never “get a price target anywhere near these levels.”

“Gambling is here,” he added. “Many will make money but history shows it is the [small] retail investor left holding the bag in the end.”

How can investors avoid being that luckless player — or perhaps even profit from populism?

One way is by buying global stocks and scarce assets such as precious metals and even cryptocurrency, Schwartzer said.

In particular, Schwartzer is bullish on Bitcoin, despite the price being up about five times her initial investment at $6,900 last April. On Friday, it closed at $34,640.

As another tactic, she recommends buying commodities.

To fight the pandemic, the Federal Reserve has doubled down on easy money and Congress has dramatically upped spending. To Schwartzer, this means inflation is coming. She says commodities are a smart haven against that.

“Both the monetary and fiscal outlook and the commodity cycle support this bullish commodities outcome in the 2020s decade,” she said.

As for the GameStop imbroglio, both sides are being demonized, and that’s not right, said Jill Fisch, a professor of securities law at the University of Pennsylvania law school

“We’re in an era of villains and heroes, people are polarized and that’s spilling over into the markets,” she said.

Short sellers have been wrongly portrayed as nefarious, she said. And so have the rebel day-traders, she said. But, Fisch added, any lawsuits challenging either would make little headway.

“Buying and selling stock isn’t manipulation. Accumulating a large position isn’t manipulation,” Fisch said. “It’s false information, making it seem you have a position you don’t have, or spreading misinformation for personal benefit” that crosses the line.