The rally in small stocks has been massive - but it comes with a warning sign. The same technology boom that powered the surge could be derailed by the very thing that once hurt them: rising interest rates.
Small-cap companies have been the forgotten corner of the market for years. Now they are suddenly the hottest trade on Wall Street.
The main driver is a massive spending wave on AI infrastructure. That spending started with big tech giants but has now reached smaller suppliers. Among the Russell 2000's 50 best-performing stocks this year, 16 are chip-related companies.
These companies do not directly compete with industry leader Nvidia. Instead, they supply testing equipment, semiconductor gear, and other components that the AI buildout requires.
Amy Zhang, portfolio manager at Alger, said, "I think a significant part of the small cap story is tied to AI. The impact of AI investment trickles down from large-cap leaders to small-cap companies. The effect will be more amplified for small-cap companies, in terms of revenue and probability growth."
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The rally is also about simple math. Small-cap stocks had been trading at a huge discount compared with large-cap stocks. That gap is now closing.
"It's both a valuation catch-up story and a fundamental story," Zhang said. "The valuation gap was so wide that a truck can drive through it. At the same time, fundamentals are improving in small caps and I think that's why it's causing the broadening trade."
Analysts now expect Russell 2000 companies' earnings to grow 38% in 2026, up from a forecast of roughly 23% at the start of the year, according to LPL Financial. That upgrade reflects the spreading AI boom.
Small-cap stocks have a problem that big companies do not: They are more sensitive to interest rates. Many small firms carry floating-rate debt. Every quarter-point hike from the Federal Reserve hits their bottom line directly.
According to Bank of America, a single quarter-point rate increase reduces Russell 2000 operating earnings by about 2%. The Fed raised rates by a total of 500 basis points between March 2022 and mid-2023, creating a huge headwind.
Now traders are worried the headwind could return.
"This could challenge the expected 4Q profits acceleration (and sentiment) in small caps, which have the most refi risk," Bank of America strategists wrote. Refi risk means the risk that companies need to refinance their debt at higher rates. For small caps, that risk is especially large.
Still, some investors believe the worst is over. "We're probably close to peak inflation and peak rates," Zhang said. "We had significant headwind the last five years, and I think the headwind is going to abate and turning into a tailwind."
LPL Financial's chief technical strategist, Adam Turnquist, noted the unusual nature of the rally. "Small-cap leadership has been notable amid the mega-cap-driven bull market, although small caps have meaningful exposure to semiconductors and technology hardware," he said. "Building fundamental strength has also helped offset headwinds from higher rates."
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