SOX index surges 50% in 25 days on AI-fueled investor frenzy

The Philadelphia Semiconductor Index (SOX) has recorded its strongest 25-day rolling gain since March 2000, climbing more than 50 percent as of Tuesday’s close in a rally that has pushed the broader market to all-time highs. The surge, fueled by massive investment in artificial intelligence, has funneled billions into chipmakers and adjacent industries.

"AI has been a tree that spreads a lot of limbs out," said Chuck Carlson, CEO at Horizon Investment Services. "That spending that is going on in that space is really a pretty significant driver."

The rally’s momentum is evident across the tech sector. On Wednesday, both the S&P 500 and the tech-heavy Nasdaq Composite set new closing records for the second straight day. Gains were led by chipmakers, with Advanced Micro Devices Inc. (AMD) soaring about 19 percent to a new record and Super Micro Computer Inc. (SMCI) jumping 25 percent after both issued strong guidance. Nvidia Corp. (NVDA), the world's most valuable company, rose 5.7 percent following a new partnership with Corning Inc.

The performance is underpinned by a robust earnings season. S&P 500 companies are on track for 28.2 percent earnings growth in the first quarter, the highest since late 2021, according to LSEG Datastream. This has helped moderate the market's valuation, with the S&P 500’s price-to-earnings ratio declining to 21.2 from a high of 23.5 in October, even as prices rise.

An Earnings Engine Fueled by AI

The driving force behind the market's ascent is the immense capital expenditure flowing into AI infrastructure. Goldman Sachs strategists project that five of the largest AI "hyperscalers" will spend $751 billion on capex in 2026 alone, primarily on data centers and the advanced chips that power them.

This spending directly translates to corporate profits. According to a Deutsche Bank report, companies and industries identified as AI beneficiaries saw their first-quarter earnings increase by 50 percent. This includes not only semiconductor firms but also a wider group of tech hardware companies, electrical equipment suppliers, and construction firms involved in building data centers. Nine of the 11 S&P 500 sectors are on pace for higher first-quarter earnings, with eight of them showing growth of at least 10 percent.

Valuation Questions and the Bubble Debate

The historic rally has inevitably sparked a debate among investors: is this a sustainable bull market built on solid fundamentals, or a speculative bubble reminiscent of the one that burst the last time the SOX saw a 25-day gain of this magnitude?

Bulls point to the record earnings growth and the long-term technological shift toward AI. The argument is that the high demand for advanced chip technology is not a fleeting trend but a structural change that will support the sector for years. The market's enthusiasm is palpable, with retail investors and institutions alike pouring into semiconductor-focused ETFs and individual stocks.

However, signs of caution are present. Some analysts worry that the rapid increase in stock prices is driven more by speculation than by fundamental value, with elevated valuations compared to historical averages suggesting stocks may be overbought. While the market has so far weathered geopolitical risks and rising energy prices, with gasoline topping $4.50 a gallon, these headwinds could eventually catch up to the economy and temper investor enthusiasm.

"For the moment, I think investors are willing to sort of ride the wave of strong earnings and generally decent economic news," said Robert Pavlik, senior portfolio manager at Dakota Wealth Management. "Eventually, $4.50-a-gallon gasoline is going to catch up to the economy, you would imagine."

This article is for informational purposes only and does not constitute investment advice.