Ten stocks fell sharply on Monday, defying broader market optimism, as investors fled their shares to shift to stocks benefiting from the artificial intelligence boom.

Meanwhile, Wall Street’s main indices all finished in the green, led by tech-heavy Nasdaq with 0.70 percent, followed by the S&P 500 with a 0.44 percent gain, the the Dow Jones, inching up by 01.14 percent.

In this article, we name the 10 worst-performing mid-cap companies on Monday and break down the reasons behind their lagging performance.

To come up with the list, we focused exclusively on stocks with a $2 billion market capitalization and 5 million shares in trading volume.

10. Celsius Holdings, Inc. (NASDAQ:CELH)

Shares of Celsius Holdings dropped for a third consecutive day on Monday, shedding 6.19 percent to close at $51.34 apiece as investor funds fled to artificial intelligence stocks amid new developments in the booming sector.

Additionally, Celsius Holdings, Inc. (NASDAQ:CELH) lacked fresh catalysts to bolster investing appetite during the session.

Despite the decline, Celsius Holdings, Inc. (NASDAQ:CELH) currently holds positive ratings from investment companies, with Zacks Research currently at a “strong buy” recommendation for its stock.

According to Zacks, it expects the company to post year-on-year growth in 2025 and 2026 earnings by 54.3 percent and 28.6 percent, respectively, as early signs suggest that its series of product launches is doing well.

Performance data from Zacks in the second quarter showed that flavor innovation is beginning to translate into repeat activity for the company.

“Variety packs and fresh flavors helped Celsius secure the number one spot among ready-to-drink (RTD) energy brands on Amazon during Prime Day, reaching an 18.4% one-week share. This kind of momentum reflects not just initial trial but strong consumer pull, with retailers reordering top sellers and featuring them during promotional periods,” Zacks said.

“Flavor innovation is not only widening [Celsius Holdings, Inc. (NASDAQ:CELH)] brand reach but also reinforcing habits, giving consumers more reasons to return to the brand rather than just try it once,” it noted.

9. NIO Inc. (NYSE:NIO)

NIO saw its share prices decline by 6.24 percent on Monday as investor sentiment was dampened by news that strong demand for a newly launched vehicle has resulted in a six-month delivery delay.

On Saturday, NIO Inc. (NYSE:NIO) officially launched the six- and seven-seater ES8 vehicle in Hangzhou, where it sold out this year’s 40,000 unit production capacity.

Amid the strong demand, NIO Inc. (NYSE:NIO) updated reservation holders on Monday that new orders would face a waiting time of 24 to 26 weeks, which means that buyers would be able to receive their vehicles as early as March 2026, or six months from now.

Buyers will be able to receive updates about the delivery of their vehicles in the Nio app. In the meantime, customers waiting for deliveries will receive “peace of mind waiting points”  equivalent to 500 points per day from the 57th day after order lock-in until successful delivery.

Last month, NIO Inc. (NYSE:NIO) announced that it delivered 31,305 vehicles, consisting of 10,525 from the Nio brand; 16,434 vehicles from Onvo; and 4,346 vehicles from Firefly.

August delivery figures were higher by 48.9 percent than the 21,207 total deliveries in July.

8. Zillow Group, Inc. (NASDAQ:Z)

Shares of Zillow Group declined for a third straight day on Monday, slashing 6.57 percent to end at $81.04 apiece as investors sold off positions following a new lawsuit that claimed the company deceived its homebuyers.

The lawsuit, which was filed in Seattle on Friday, claimed that Zillow Group, Inc. (NASDAQ:Z) misled prospective buyers into contacting agents working with the company, and not the agent who listed the homes for sale.

According to the plaintiff, who is a resident of Oregon, the said practices violate a Washington state consumer protection law and a federal real estate law.

“Zillow is well aware of the potential for ill-gotten gains in this space and has sought to play fast and loose when real people’s basic need for housing is on the table,” a lead attorney was quoted as saying in the lawsuit.

Meanwhile, Zillow Group, Inc. (NASDAQ:Z) said in a statement that it would defend itself from the claims, saying that the lawsuit was a misrepresentation of how the company operates.

It said it stands by its “long-held belief that buyers and sellers deserve to have the choice to work with an agent who is committed to their best interests and only represents them.”

7. Magnite, Inc. (NASDAQ:MGNI)

Shares of Magnite snapped a three-day winning streak on Monday, shedding 6.79 percent to finish at $24.16 apiece as investor funds fled to artificial intelligence stocks amid fresh developments surrounding the booming sector.

Additionally, investors sold off positions amid lingering concerns for its legal battle with Google LLC, having filed a new lawsuit against the latter last week.

In a regulatory filing, Magnite, Inc. (NASDAQ:MGNI) said that it sued Google and sought financial damages in light of the U.S. District Court’s ruling that Google had engaged in unlawful anticompetitive practices with respect to certain ad tech markets.

It acknowledged Google as a significant participant in the digital advertising ecosystem, underscoring that it is both a major partner and competitor to Magnite, Inc. (NASDAQ:MGNI), where a significant portion of its revenue comes from.

“Magnite was founded to help publishers thrive by maximizing their advertising yield through innovative technology, trusted guidance, and a transparent marketplace that efficiently connects them to buyers, ” Magnite, Inc. (NASDAQ:MGNI) CEO Michael Barrett said.

“For years, Google undermined our ability to execute on this mission with practices that favored its own business over the health of the open web, causing harm to publishers, advertisers, and partners like us. We look forward to a future that promotes healthy competition, ongoing innovation, and value creation for the ecosystem as a whole,” he noted.

6. Kenvue Inc. (NYSE:KVUE)

Shares of Kenvue Inc. (NYSE:KVUE) fell to a new all-time low after President Donald Trump linked autism to the use of Tylenol during pregnancy.

During the session, shares of the company dropped to its lowest 52-week price of $16.89 before ending the day down by 7.47 percent at $16.97 apiece.

In an extraordinary conference at the White House, Trump delivered advice to pregnant women and parents of young children, telling them not to take over-the-counter painkillers.

“I want to say it like it is, don’t take Tylenol. Don’t take it,” Trump said. “Fight like hell not to take it. There may be a point where you have to, and that you’ll have to work out with yourself, so don’t take Tylenol.”

Trump, who was seated beside anti-vaccine Health Secretary Robert F. Kennedy Jr., called for the reexamination of a link between vaccines and autism.

Kenvue Inc. (NYSE:KVUE), maker of Tylenol, issued a statement to defend its product shortly after Trump’s statement.

“We believe independent, sound science clearly shows that taking acetaminophen does not cause autism. We strongly disagree with any suggestion otherwise and are deeply concerned with the health risk this poses for expecting mothers,” Kenvue Inc. (NYSE:KVUE) said.

5. Bitmine Immersion Technologies, Inc. (NYSEAmerican:BMNR)

Bitmine Immersion snapped a four-day winning streak on Monday, shedding 10.10 percent to finish at $55.10 apiece as investors disposed of shares following plans to raise $365.24 million from the sale of new shares.

In a statement, Bitmine Immersion Technologies, Inc. (NYSEAmerican:BMNR) said it entered into a securities purchase agreement with an institutional investor for the sale of more than 5.2 million common shares at a price of $70 apiece, alongside warrants to purchase up to 10.4 million shares at an exercise price of $87.50.

The $70 price alone represents a 14-percent premium over its closing price on September 19. Meanwhile, the warrants will be exercisable upon issuance and expire on March 22, 2027.

Investors turned on sour on the news as it would result in the dilution of existing shares.

“BitMine has raised $365.24 million by selling our stock at a 14 percent premium to Friday’s close. By selling shares at $70 per share…this is materially accretive to existing shareholders as the primary use of proceeds is to add to our ETH holdings,” said Bitmine Immersion Technologies, Inc. (NYSEAmerican:BMNR)  Chairman Thomas Lee.

“In our view, this 14 percent premium reflects not only strong institutional investor interest in the BitMine story, but also confidence in our execution as a Company,” he added.

“Institutional investors have told us BitMine remains the only large-cap US stock to give investors direct exposure to Ethereum. Our August Chairman’s message resonates with many investors, who see the compelling supercycle for Ethereum as Wall Street moves to embrace and build upon this blockchain.”

4. Opendoor Technologies Inc. (NASDAQ:OPEN)

Shares of Opendoor Technologies dropped for a third consecutive day on Monday, losing 12.43 percent to end at $8.38 apiece as investor funds shifted to higher-yielding assets such as AI stocks and precious metals, after skyrocketing during the session.

In intra-day trading, technology stocks, particularly those benefitting from the artificial intelligence boom, took center stage on Monday after Nvidia Corp. announced a fresh $100 billion investment in OpenAI. The good news spilled over to industries expected to benefit from the AI wave, including semiconductors and data infrastructures.

Additionally, the drop suggested that investors have priced in fresh developments in Opendoor Technologies Inc. (NASDAQ:OPEN), with the return of its founders and the naming of a new chief executive to support its turnaround and revival, while continuing to take profits after surging to new heights on Thursday.

As of Tuesday, shares of Opendoor Technologies Inc. (NASDAQ:OPEN) already marked a whopping 88.3 percent gain month-to-date.

3. Quantum Computing Inc. (NASDAQ:QUBT)

Quantum Computing snapped a four-day winning streak on Monday, losing 13.15 percent to end at $20.21 apiece after announcing a $500 million share sale that could result in the potential dilution of existing shares.

In a statement, Quantum Computing Inc. (NASDAQ:QUBT) said it entered into a share purchase agreement with institutional investors for the purchase of more than 26.8 million common shares for $500 million, or equivalent to $18.6 per share.

The offer is expected to close on Wednesday, September 24, subject to the satisfaction of customary closing conditions.

Quantum Computing Inc. (NASDAQ:QUBT) said it plans to use the proceeds to accelerate commercialization efforts, strategic acquisitions, expand sales and engineering personnel, working capital, and general corporate purposes.

“This successful $500 million offering, led by strong support from both new and existing leading institutional investors, is priced at a substantial premium to our four recent offerings, bringing our total gross capital raised since November 2024 to approximately $900 million,” said Quantum Computing Inc. (NASDAQ:QUBT) Chairman and CEO Yuping Huang.

“This financing further fortifies our financial position and enables us to execute our multi-year growth plan, including the acceleration of commercialization efforts, strategic acquisitions, the expansion of sales and engineering personnel, and the strengthening of our manufacturing capabilities,” he noted.

2. Compass, Inc. (NYSE:COMP)

Compass saw its share prices decline by 15.74 percent on Monday to end at $7.92 as investors unloaded positions after announcing plans to acquire Anywhere Real Estate for $10 billion.

In a statement, Compass, Inc. (NYSE:COMP) said it signed a definitive merger agreement with Anywhere Real Estate Inc. (NYSE: HOUS) to combine in an all-stock transaction.

Under the agreement, each share of Anywhere common stock will be exchanged for 1.436 shares of Compass Class A common stock, which represents a value of $13.01 per Anywhere common stock share based on Compass’ 30 trading day volume weighted average price as of September 19, 2025.

Upon completion of the transaction, current shareholders of Compass, Inc. (NYSE:COMP) will own approximately 78 percent of the combined company on a fully diluted basis, while Anywhere shareholders will own approximately 22 percent.

Compass, Inc. (NYSE:COMP) said the transaction pairs its investments in technology, innovative market offerings, and real estate professionals with Anywhere’s leading brands, broader and complementary businesses, and global reach.

The merger will bring together approximately 340,000 real estate professionals globally onto a shared network operating in every major US city and serving approximately 120 countries and territories.

1. Cosan SA (NYSE:CSAN)

Cosan extended its losing streak to a third straight day on Monday, shedding 17.84 percent to end at $4.65 apiece as investor sentiment was dampened by plans to raise its capital through a public offering worth $2 billion in a bid to reduce its mounting debts.

In a regulatory filing, Cosan SA (NYSE:CSAN) said it entered into an investment agreement with BTG Pactual Holding and Perfin Infra Administração de Recursos Ltda. for two rounds of share sales to be offered in Brazil.

The first public offering will see the primary issuance of 1.45 billion common shares, which may be increased by 362.5 million shares to the said investors, to be followed by the sale of 550 million shares.

The investors have committed to subscribe to the shares at a price of R$5.00.

“The funds raised by the Company in the Public Offerings will be used by the Company exclusively for renegotiation and repayment of its financial debts, in order to effectively reduce its financial leverage,” Cosan SA (NYSE:CSAN) said.

The company expects to close the first public offering on November 14, 2025.

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