In turn, shares of GameStop soared by more than 30 percent by midday trading, with the video game retailer carrying a valuation of nearly $10 billion.

Gill's original $53,000 bet in GameStop set into motion the extraordinary short squeeze involving the company in 2021. It was cast as a David and Goliath saga -- one that gripped the nation, enriched Gill and many of his online followers, and sent seasoned Wall Street investors reeling.

But as quickly as he came on the scene, Gill, a Brockton native, disappeared, with his social media accounts going radio silent just months after the short squeeze. He re-emerged in mid-May, posting a photo on his X account of a man sitting forward in his chair. That missive alone caused GameStop stocks to surge, along with other popular meme stocks -- sentimental stocks that hedge funds have bet will flounder -- such as theater chain AMC and phone maker BlackBerry.

As Gill continues his comeback, here are four things to know about the enigmatic market mover.

Before his notoriety for running circles around Wall Street investors, Gill excelled at a different kind of running: track, at Brockton High School, and then Stonehill College in Easton, where he graduated with a major in accounting.

But he lived in Wilmington by the time he was drawing hordes of retail trader enthusiasts to his Roaring Kitty YouTube account, where he would conducts hours-long, live-streamed commentary about his investments. According to an interview with the Wall Street Journal, he conducted these live-streams from his basement of the home he rented and shared with his wife, Caroline, and their young daughter.

It is unclear whether Gill still lives in Massachusetts.

Prior to his ascension to retail trader folk hero, Gill had a day job: director of financial wellness education at MassMutual, a Springfield-based insurer and financial services giant. He resigned around the time shares of GameStop took off.

Much of Gill's legal troubles following the rally involved his employment at MassMutual -- namely, whether he was permitted to promote the GameStop stock on social media while he worked at the company as a registered broker-dealer agent. State regulators subpoenaed both him and his former supervisors, ultimately levying a $4 million fine on the subsidiary of MassMutual that employed Gill.

"MassMutual was not as diligent as it should have been in supervising its employees," said the office of Secretary of the Commonwealth William Galvin at the time.

After Gill's social media activity landed him in hot water with regulators, it also embroiled him in a lawsuit in the United States District Court for the District of Massachusetts that was only recently resolved.

Douglas Rosenberg, an investor living in Washington, claimed in a lawsuit filed in February of 2023 that he lost $1.2 million on option contracts and shorted shares of GameStop as a result of "Gill's conspiracy to raise the price of GME Stock."

It wasn't until April 22, 2024, that Rosenberg, who was representing himself in the matter, opted to voluntarily dismiss the case.

Less than a month later, Gill resurfaced on social media.

It didn't take long for Gill's escapades to get the Hollywood treatment.

Just a week after the 2021 rally, it was announced that Boston author Ben Mezrich would pen a behind-the-scenes account of the frenzy; at the same time, MGM snapped up the rights to the book proposal.

The resulting book, "The Antisocial Network: The GameStop Short Squeeze and the Ragtag Group of Amateur Traders That Brought Wall Street to Its Knees," was published in September of 2021. The accompanying star-studded film, "Dumb Money," came out last September, with Paul Dano ("Little Miss Sunshine," "The Batman") appearing as Gill, bedecked in the trader's signature red headband and graphic tees.

While the GameStop phenomenon has undoubtedly altered Gill's life, his influence has extended beyond his own personal gains. Retail traders, often congregating on forums like Reddit's r/WallStreetBets, have viewed Keith Gill's actions as a blueprint for tackling shorted stocks and banding together to challenge institutional investors. This grassroots movement has shifted the perception of individual investors and their ability to impact the market.

The power shift from traditional Wall Street to the hands of retail investors has sparked widespread conversation about market regulation and the role of social media in trading. Following the GameStop surge, federal agencies, including the Securities and Exchange Commission (SEC), have looked into the volatility of stocks associated with retail trading frenzy. Discussions have centered on market manipulation, the gamification of trading through apps like Robinhood, and the need for greater transparency in the financial industry.

Gill's legacy as a central figure in this market upheaval continues to evolve. Retail traders have become more sophisticated and vigilant, closely following influencers with substantial followings like Gill for investment strategies. However, the SEC has also issued warnings to influencers about their responsibilities and the potential legal ramifications of offering investment advice without proper qualifications or disclosures.

Despite the challenges, the enthusiasm around meme stocks has not waned. GameStop's success has been a catalyst for a broader movement that challenges the status quo of investing. The democratization of financial information, expedited by the rapid spread of data through social media platforms, has empowered a new wave of traders. They're now deeply involved in the financial markets with their collective actions, upending expectations and providing stiff competition to hedge funds and veteran traders.

The cultural impact of the GameStop saga extends further with talks of more films and documentaries in the works that aim to capture the essence of this modern financial uprising. These narratives are not just about the financial implications but also the underlying storyline of empowerment and the breaking of barriers in the exclusive world of finance.

As the world watches, Keith Gill's influence persists, illustrating the potency of viral influence in the digital age. His story is far from over - it remains to be seen how his actions will continue to shape market dynamics and regulatory landscapes in the years ahead. All eyes remain on Gill and the fluctuating shares of GameStop, as market watchers anticipate the next chapter in this unprecedented financial tale.