S&P 500 Rollercoaster: Moderna Tanks 15% While Synopsys Soars on Nvidia Mega-Deal

Tech stocks steal the show as Synopsys rides the AI hype wave—meanwhile, Moderna's mRNA bet goes limp.

Synopsys surges 12% after inking a chip design deal with Nvidia—proof that hanging around the AI cool kids pays off. Meanwhile, Moderna plunges as investors realize 'pandemic darling' isn't a permanent job title.

Wall Street's latest mood swing: dumping biotech for silicon. Because nothing says 'stable investment' like betting on unproven tech at all-time highs.

Key Takeaways

• Worries about regulatory headwinds weighed on vaccine producers on Monday, Dec. 1, 2025, while a chip design software maker got a boost from a partnership with an AI darling. 
• Moderna shares dropped after a report that U.S. health regulators plan to adopt a stricter process for approving vaccines.
• Shares of Synopsys, which specializes in software used in the semiconductor design process, powered higher following the announcement of a collaboration with Nvidia.

A major vaccine producer came under pressure following a report federal health regulators plan to tighten vaccine approval rules. Meanwhile, an agreement with the world's most valuable company bolstered a software firm whose products help customers design and test semiconductors.

Major U.S. equities indexes lost ground to start December after a strong week to end November. The Nasdaq slipped 0.4%, the S&P 500 fell 0.5%, and the Dow dropped 0.9%. See here for more from Investopedia on the day's market moves.

Shares of Moderna (MRNA), which makes the bulk of its revenue from its COVID-19 vaccine, tumbled 7% to lead losses on the S&P 500 after a report the Food and Drug Administration plans to overhaul its process for evaluating vaccines, requiring more evidence of safety and efficacy prior to approval. Novavax (NVAX), BioNTech (BNTX), and Pfizer (PFE) also slid.

Shares of Sandisk (SNDK), a Maker of memory cards and other data storage products, dropped close to 6%. With the move lower Monday, Sandisk reversed gains last week on enthusiasm for the stock's S&P 500 debut. Despite the decline to start December, Sandisk shares have still notched big gains since the company completed its spinoff from Western Digital (WDC) in February, bolstered by AI-driven memory demand.

Despite showing signs of a possible recovery last week, the price of Bitcoin (BTCUSD) and other major cryptocurrencies plunged Monday. Shares of crypto exchange operator Coinbase Global (COIN) fell about 5%, while shares Robinhood Markets (HOOD), which offers access to crypto on its trading platform, lost 4%.

Synopsys (SNPS) shares jumped around 5% after the provider of electronic design automation software announced an expanded partnership with AI chip leader Nvidia (NVDA). Under the terms of the deal, Nvidia is investing $2 billion in Synopsys, and the two companies will collaborate on agentic and physical AI applications. Nvidia stock added 1.7% Monday.

Shares of footwear and apparel company Deckers Outdoor (DECK) ROSE 4.5%. Late last month, analysts at Stifel upgraded Deckers stock to "buy" from "hold," pointing to an upbeat growth outlook for the company's Hoka shoe brand, solid demand for the Ugg brand, and a strong international sales. The company offered rare discounts on Hoka sneakers for Black Friday.

A pair of transport and logistics companies also got a boost following bullish comments from analysts at BMO Capital. Old Dominion Freight Line (ODFL) and J.B. Hunt Transport Services (JBHT) shares each added over 3% after BMO analysts issued "outperform" ratings for the stocks.