The biggest S&P 500 movers heading into the year’s end
The market has been anything but boring this year. Between the AI boom, energy-sector shake-ups, political tension, and a whole lot of investor mood swings, we’ve seen some dramatic moves in both directions. Some companies have rocketed to new highs on genuine momentum, while others have stumbled hard under shifting expectations and tougher competition.
As we head into the final weeks of 2025, let’s break down the S&P 500’s top five biggest winners and losers of the year — and why they’ve landed where they are.
Top 5 stock winners of 2025
These are the top five S&P 500 stock winners going into the final month of the year, using data from Finviz.
1. Western Digital (WDC) (+263%)
Western Digital has surged thanks to the explosive growth in AI and data-center demand, securing its position as S&P 500 leader through November with a 263% gain.
Enterprises and cloud providers are gobbling up high-capacity storage, and Western Digital’s legacy in hard drives and new technologies is paying off big.
That said, much of Western Digital’s success hinges on continued AI-infrastructure investment — if cloud and storage spending slows or new storage technologies emerge, it could temper future gains.
2. Robinhood (HOOD) (+231%)
Robinhood has benefited from renewed interest from retail investors and its expansion into crypto, financial services, and prediction markets, sending its stock soaring in 2025.
The company is off to a strong start in Q4, driven by record trading volumes. It’s also seeing its business diversification efforts pay off — Robinhood’s Prediction Markets and Bitstamp are both generating about $100 million or more in annualized revenues. What’s more, Robinhood’s predictions market business has rapidly emerged as its fastest-growing revenue segment. In just one year since its debut, over 1 million Robinhood users have traded 9 billion contracts.
But because its upside is tied heavily to investor sentiment and trading volume, any cooling retail activity or regulatory uncertainty might challenge its momentum.
3. Seagate Technology (STX) (+213%)
Seagate is riding the same storage wave as Western Digital, bolstered by surging demand for high-capacity drives from data-center and cloud customers. According to its most recent earnings report, the company logged $2.63 billion in revenue, up 21% year-over-year, and a record non-GAAP gross margin of 40.1%.
Management said roughly 80% of revenue came from nearline sales into cloud, enterprise, and VIA customers, with long-term build-to-order contracts now committed through 2026 — offering good visibility and reinforcing confidence that demand for high-capacity storage will remain strong.
Even with their growing SSD lineup and next-gen high-capacity HDDs, Seagate’s business still leans heavily on these traditional drives, so any rapid shift in how companies store data could shake up their revenue mix a bit.
4. Micron Technology (MU) (+186%)
Micron has benefited from the boom in AI hardware demand, with DRAM and NAND chips essential for data-center memory and AI workloads. Memory chips are crucial for everything from AI training to cloud computing, and Micron’s leadership in DRAM and NAND production has investors excited.
Micron closed out fiscal 2025 with record revenue of $11.3 billion in Q4, driven by surging demand for memory in data-center and AI workloads.
The company said its data center business now accounts for the bulk of revenue, and its advanced HBM chips and G9 NAND SSDs are helping it secure strong demand for 2026.
Still, the memory chip market is famously cyclical. If supply overshoots demand or macro conditions worsen, Micron could see volatility heavier than what we’ve seen this year.
5. Newmont (NEM) (+146%)
Gold and precious metals have rallied in 2025, as concerns about inflation and market volatility continue. Newmont, a leading gold miner, has seen strong gains thanks to this safe-haven appeal, making it one of the top-performing S&P 500 stocks this year.
In Q3 2025, Newmont generated a record $1.6 billion in free cash flow — marking the fourth straight quarter with more than $1 billion in free cash flow.
The company also sharpened its 2025 cost and capital guidance thanks to ongoing cost-savings efforts and a shift in the timing of capital spending.
Still, the rally is sensitive to macroeconomic shifts: if inflation eases or interest rates rise, Newmont’s performance could temper, even with its strong year.
Top 5 stock losers in 2025
- Fiserv (FISV) (-70%): Falling demand for certain payment solutions and competitive pressure in fintech have weighed heavily on Fiserv’s stock. Investors are reassessing growth expectations and margins.
- The Trade Desk (TTD) (-66%): The digital advertising space has cooled off, and Trade Desk has been hit by slower client spending and declining ad growth from tariff uncertainty.
- Deckers Outdoor (DECK) (-55%): Deckers, known for UGGs and other footwear brands, has struggled with supply chain costs, pricing pressure, and changing consumer habits, leading to significant stock losses.
- Gartner (IT) (-52%): The research and advisory firm Gartner has been hit by slowing research demand and growing AI competition, forcing the company to cut its annual revenue forecast.
- Lululemon Athletica (LULU) (-52%): Lululemon has faced softness in consumer spending and tough comparisons from prior years. Rising costs and competition in the athleisure market have also pressured margins.
Bottom line
AI infrastructure was the defining market force of 2025, powering huge gains for storage and memory names like Western Digital, Seagate, and Micron. Meanwhile, retail participation surged, with Robinhood capitalizing on renewed trading enthusiasm and expanding into new products. Safe-haven demand also resurfaced, helping Newmont capitalize on a strong year for gold.
On the flip side, sector rotation hit digital advertising, retail, and IT services hard, dragging down stocks like Trade Desk, Deckers, Lululemon, and Gartner. And with December still ahead, volatility remains firmly on the table as investors reassess valuations and macro risks heading
