Wall Street Starts December with Limited Pullback: Key Market Moves and Analysis (2025)

• Why Did U.S. Markets Open Lower in December?
• Synopsys Soars on Nvidia’s Strategic Bet
• Manufacturing Data: A Tale of Two Surveys
• Airbus Woes Ground American Airlines
• Goldman Sachs Bets $2B on ETF Innovator
• Eli Lilly Slashes Zepbound Prices
• Micron’s $9.6B HBM Play in Japan
• FAQ: Quick Takes on Today’s Market Moves

U.S. markets kicked off December with a slight dip as manufacturing data disappointed, while strategic investments and sector-specific news drove volatility. The Dow Jones and Nasdaq Composite edged lower, but Synopsys surged on Nvidia’s $2 billion stake. Meanwhile, Micron’s $9.6 billion Japan plant and Eli Lilly’s price cuts for Zepbound stole headlines. Here’s a breakdown of the day’s top financial moves and what they mean for investors.

Why Did U.S. Markets Open Lower in December?

U.S. stocks began December in the red, with the Dow Jones slipping 0.49% to 47,480.40 points and the Nasdaq Composite down 0.38% to 23,277.24 points. The dip followed weaker-than-expected manufacturing data from the Institute for Supply Management (ISM), which reported a contraction to 48.2 in November from 48.7 in October. Analysts had anticipated 49. S&P Global’s competing index showed a milder slowdown at 52.2 (vs. 52.5 in October), but the mixed signals weighed on sentiment. The dollar also softened, adding to the cautious tone.

Synopsys Soars on Nvidia’s Strategic Bet

Chip design software firm Synopsys jumped 3.42% to $432.31 after Nvidia announced a $2 billion investment to deepen their collaboration. The deal aims to “revolutionize industrial design and engineering” by enhancing R&D teams’ ability to simulate and verify products faster and cheaper. Nvidia shares rose 1.05% to $178.85. This partnership underscores the growing demand for AI-driven design tools—something we’ve seen explode since 2023’s generative AI boom.

Manufacturing Data: A Tale of Two Surveys

The ISM’s gloomy report contrasted with S&P Global’s marginally better figures, highlighting the sector’s uneven recovery. While ISM’s sub-50 reading signals contraction, S&P’s above-50 score suggests expansion—albeit slower. This divergence isn’t new; ISM focuses on larger firms, while S&P includes smaller players. For context, the 10-year average for ISM’s index is 52.7, so today’s numbers reveal lingering post-pandemic adjustments.

Airbus Woes Ground American Airlines

American Airlines flagged operational delays due to Airbus’s issues with 6,000 A320 jets, per Reuters. While most planes were retrofitted, under 100 remain unresolved. JetBlue canceled 20 flights over the same snag. Airbus assured it’s working “closely with carriers,” but supply-chain hiccups persist—a reminder of 2024’s aerospace bottlenecks.

Goldman Sachs Bets $2B on ETF Innovator

Goldman Sachs agreed to buy Innovator Capital Management, a pioneer in defined-outcome ETFs, for $2 billion (cash and stock). Innovator oversees $28 billion across 159 ETFs as of September 2025. This acquisition aligns with Goldman’s push into passive products—a trend accelerating since BlackRock’s iShares dominance.

Eli Lilly Slashes Zepbound Prices

Eli Lilly cut prices for single-dose Zepbound vials on its digital health platform, LillyDirect, to reduce out-of-pocket costs for obesity patients. Last month, it also trimmed multi-dose pen prices pending FDA approval. With obesity drugs like Zepbound and Novo Nordisk’s Wegovy in a sales arms race, affordability could be a game-changer.

Micron’s $9.6B HBM Play in Japan

Micron Technology plans a $9.6 billion plant in Hiroshima to produce cutting-edge high-bandwidth memory (HBM) chips by 2028, per Nikkei. The MOVE counters Samsung and SK Hynix in the AI-driven HBM market, which Bloomberg estimates will grow 40% annually through 2030. Construction starts May 2026—right as AI chip demand peaks.

FAQ: Quick Takes on Today’s Market Moves

Why did Synopsys stock rise?

Synopsys gained 3.42% after Nvidia’s $2 billion investment to jointly develop advanced design tools for AI and industrial applications.

What’s the outlook for U.S. manufacturing?

ISM data suggests contraction (48.2), but S&P Global’s index (52.2) indicates slower growth. The divide reflects differing sample sizes and methodologies.

How significant is Micron’s Japan investment?

At $9.6 billion, it’s Micron’s largest HBM production commitment yet, targeting AI chip demand. HBM revenue could hit $30 billion by 2030, per TrendForce.