S&P 500 hits record high amid warning signs for Trump's AI rally

The stock market keeps climbing walls investors barely seem to notice anymore. The S&P 500 just hit another all-time high, extending a rally that has added nearly 50% since the tariff-driven panic low in April 2025. 

President Donald Trump’s tax cuts, deregulation push, and pro-business policies embedded in the One Big Beautiful Bill Act have helped fuel that surge. Corporate profits remain healthy, unemployment is low, and artificial intelligence spending continues pouring rocket fuel on Big Tech earnings.

But beneath the surface, something looks off. And history suggests smart investors should pay attention.

An Historic Warning Sign Just Flashed

On Friday, the S&P 500 reached a fresh record high while 5.6% of its components simultaneously hit new 52-week lows. Independent investment research firm Hedgeye Risk Management notes this has only happened three other times in history:

• July, 1929

• January, 1973

• December, 1999

That is not exactly comforting company. Those dates came shortly before three of the worst bear markets investors have ever endured. The 1929 peak preceded the Great Depression crash. The 1973 signal arrived before the brutal stagflation-era collapse and the onset of the so-called “Lost Decade.” December 1999 marked the final euphoric stage of the dot-com bubble.

Granted, history does not repeat perfectly. Markets are driven by different economic conditions, different Federal Reserve policies, and different technologies every cycle. But market breadth deterioration this severe while indexes make new highs is rare for a reason. The market’s headline numbers may be hiding weakness underneath.

The Trump Bull Market Is Narrower Than It Looks

President Trump’s economic agenda has unquestionably helped ignite investor optimism. The extension of corporate tax cuts, accelerated depreciation rules, and regulatory reforms through the OBBBA boosted expectations for earnings growth across multiple sectors.

According to Treasury Department estimates, lower effective tax burdens are expected to save large corporations tens of billions annually. Investors responded exactly how you would expect — by bidding stocks higher.

The problem is that the gains are increasingly concentrated in a small handful of companies. Right now, mega-cap technology stocks including Nvidia (NASDAQ:NVDA | NVDA Price Prediction), Alphabet (NASDAQ:GOOG)(NASDAQ:GOOGL), and Meta Platforms (NASDAQ:META) dominate index performance. Collectively, Big Tech now accounts for roughly 38% of the S&P 500’s total weighting. That concentration matters enormously.

When just a few stocks become that dominant, they can drag the entire index higher even while hundreds of companies struggle.

Surprisingly, many S&P 500 members are already flashing warning signs. Industrials, regional banks, consumer discretionary companies, and smaller healthcare names have lagged badly despite the market’s record highs. Some are already in bear markets individually.

In any case, investors looking only at the index level could easily miss the growing cracks underneath.

Don’t let the bull market fool you. Beneath the surface, the same red flags that preceded 1929 and 1999 are flashing once again. © 24/7 Wall St.

AI Euphoria Is Starting to Resemble 1999

The current rally has one undeniable engine: artificial intelligence.

Companies tied to AI chips, cloud infrastructure, data centers, and automation spending have attracted enormous investor capital. Nvidia alone added trillions in market value in less than two years as demand for AI accelerators exploded.

That enthusiasm may be justified over the long term. AI could reshape the global economy for decades. But valuations matter.

The Shiller P/E ratio — also known as the CAPE ratio — now sits near its second-highest reading in history, according to data from economist Robert Shiller. The only period that exceeded today’s valuation levels was November 1999. That comparison should make investors pause.

The CAPE ratio smooths earnings over 10 years to remove temporary economic distortions. Historically, elevated CAPE readings have correlated with lower long-term returns and higher crash risk. 

It means investors today are paying some of the richest valuations ever recorded for future earnings growth that may take years to fully materialize. If AI spending cools, earnings disappoint, or economic growth slows, those valuations leave little room for error.

That said, this does not guarantee a crash tomorrow morning. Bull markets can stay expensive longer than investors expect. Momentum can persist for months or even years.

Regardless of how you look at it, though, the combination of narrow breadth, concentrated leadership, and historically stretched valuations creates a setup investors cannot afford to ignore.

Key Takeaway

In short, the Trump bull market remains powerful — but it is increasingly dependent on a shrinking group of AI-driven mega-cap stocks to keep moving higher.

History shows that when indexes hit record highs while large portions of the market simultaneously hit new lows, investors should pay attention. The last three times it happened came shortly before major market downturns.

That does not mean investors should panic or abandon stocks entirely. But it does mean sharp investors may want to review portfolio concentration, rebalance oversized technology positions, and keep some dry powder available if a dramatic market crash occurs.

The stock market’s biggest danger may not be economic weakness at all. It may be the growing belief that the rally can never end.