Biggest Stock Movers Today, Dec. 8: CFLT, UL, & More

Investors came into the new week on Monday largely in wait-and-see mode, as the Federal Reserve will begin its two-day December meeting on Tuesday. The central bank's latest pronouncement on interest rates, which it will make on Wednesday afternoon, will play a huge role in investor sentiment heading into the remainder of the holiday season and into 2026. For now, though, investors didn't see anything that warranted large moves in the primary market benchmarks. The Nasdaq Composite (NASDAQINDEX: ^IXIC), S&P 500 (SNPINDEX: ^GSPC) , and Dow Jones Industrial Average (DJINDICES: ^DJI) all saw relatively modest declines on the day.

Data source: Yahoo! Finance.

Despite the relatively calm trading session, several individual stocks saw much larger moves on Monday. Read on to learn more about some high-flying companies as well as a couple of large businesses that have suffered some recent setbacks.

Image source: The Motley Fool.

Top Stock Gainers Today

CFLT: +29%

Confluent (NASDAQ: CFLT) jumped on news that tech behemoth IBM (NYSE: IBM) had entered into an agreement to acquire the open-source data streaming company. Under the terms of the deal, Confluent shareholders will receive $31 per share in cash for their stock, valuing the company at $11 billion. As IBM sees it, integrating Confluent into its own technology platforms will allow the two companies' joint enterprise customer bases to deploy new generative and agentic AI solutions more effectively than they could separately. Meanwhile, Confluent co-founder/CEO Jay Kreps was excited by what joining Big Blue could mean for his company. Given the pace at which AI service providers are scrambling to scale up their businesses to meet unprecedented demand, it wasn't surprising to see that IBM shares also managed to gain a bit of ground Monday -- something that's relatively unusual for an acquirer making a major purchase of an AI stock.

WVE: +147%

A lesser-known company led the list of top stock market gainers on Monday. Wave Life Sciences (NASDAQ: WVE) soared nearly 150% during the regular session after the clinical-stage biopharmaceutical company announced positive results from a trial of its investigational obesity treatment. Wave's WVE-007 produced improvements in body composition, including reductions in fat mass and increases in lean mass after three months. Wave also demonstrated a favorable safety profile for the candidate treatment.CEO Paul Bolno said that the results exceeded Wave's expectations and put WVE-007 on a similar level as GLP-1 weight-loss drugs. In addition, with the potential to let patients take WVE-007 just once or twice per year, Wave hopes that patients could eventually be able to enjoy favorable health benefits without the need for more frequent injections.

Top Stock Losers Today

UL: -7%

Shares of global consumer products giant Unilever (NYSE: UL) were down on Monday, but don't let the decline trick you. The move follows the company's spinoff of its Magnum Ice Cream (NYSE: MICC) unit, which started trading as an independent company on Monday. Unilever shareholders who held shares last Friday were entitled to receive one share of Magnum stock for every five Unilever shares they held, but Monday's buyers of Unilever stock were no longer eligible. Magnum, which also owns the popular Ben & Jerry's ice cream brand, didn't get a huge bump out of the gate, but many investors believe that the ice cream unit could fare better on its own than it has under the thumb of the massive consumer stock's global empire.

APD: -9%

Finally, Air Products and Chemicals (NYSE: APD) dropped over 9% on the day. The maker of industrial gases and chemicals said that it is in advanced negotiations with Norway's Yara International to create a new partnership. Air Products would contribute its industrial gas capabilities as well as its exposure to low-emission hydrogen, while Yara would bring its ammonia production and distribution network to the table. Despite the potential benefits of the deal, investors seem to believe that the amount of capital required for the investment could put pressure on Air Products' balance sheet. More broadly, hydrogen projects haven't seen as much success as some investors had hoped, but a deal would mean Air Products would have more at risk if the two parties reach a final agreement.

Dan Caplinger has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends International Business Machines. The Motley Fool recommends Confluent and Unilever. The Motley Fool has a disclosure policy.