The hidden warning beneath record stock market highs
Oct 5, 2026 1:00 PM
· YahooFinance
When bond markets and equity markets disagree, one of them is eventually forced to adjust
One of the most dangerous signals in investing is when market indexes tell a very different story from the underlying data.
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Today, the S&P 500 sits near record highs, suggesting investors remain optimistic about economic growth, corporate profits and the future. Yet beneath the surface, the average stock is struggling. Market leadership has narrowed dramatically, participation is deteriorating and an increasing number of companies are already in bear market territory.
Roughly 60 per cent of S&P 500 constituents are down more than 20 per cent from their individual highs. Market breadth has been this weak only twice before: during the 1973–74 bear market and at the peak of the technology bubble in 1999–2000.
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The same divergence is evident when comparing the equal-weighted S&P 500 with its traditional capitalization-weighted counterpart. The ratio between the two has fallen to one of its lowest levels since 2003. Driven almost entirely by the growing concentration of mega-cap technology and artificial intelligence stocks, the ratio is on track for a fourth consecutive annual decline, a pattern not seen since the final stages of the dot-com boom.
In many ways, this is no longer a broad-based bull market. It is a market being carried by a remarkably small group of companies tied to a single narrative: artificial intelligence.
The problem is that the sector carrying the market is also one of the largest consumers of capital. Building the AI infrastructure of the future requires enormous investment in data centres, semiconductor manufacturing, power generation and transmission networks. According to a recent Brookings Institution study, financing the AI buildout could exceed US$10 trillion between 2025 and 2032.
The challenge is that this spending does not occur in isolation. The same pool of capital required to finance AI infrastructure must also absorb massive amounts of new U.S. Treasury issuance as Washington continues to run large fiscal deficits.
This is where the bond market enters the story.
While equity investors remain focused on AI growth projections, bond markets appear increasingly focused on a different question: Who will finance both the AI buildout and Washington’s borrowing needs?
Rising term premiums suggest investors are demanding greater compensation for holding long-dated bonds, pushing yields higher even as many market participants continue to expect interest-rate relief. In effect, the bond market may be signalling that the supply of debt is beginning to overwhelm demand.
Historically, investors have paid a price for ignoring similar warnings.
During the late stages of the dot-com boom between 1998 and 2000, bond market volatility began rising as the U.S. Federal Reserve tightened policy and liquidity conditions deteriorated. Equity investors largely ignored the warning, with technology stocks continuing to surge for many months before the bubble burst and the S&P 500 ultimately lost roughly half its value.
A similar divergence emerged in 2007. Treasury and credit markets began flashing warning signs well before equities peaked. Bond market stress increased throughout the summer while the S&P 500 continued climbing to new highs into October. Within a year, investors found themselves in one of the worst bear markets in modern history.
More recently, bond volatility surged in 2018 as the Federal Reserve tightened policy and 10-year Treasury yields approached 3.25 per cent. Equities initially shrugged off the move before suffering a near 20 per cent correction during the fourth quarter. In 2022, bond markets again led the warning as inflation and aggressive rate hikes triggered a sharp rise in fixed-income volatility. The S&P 500 eventually followed, falling roughly 25 per cent peak to trough.
To be clear, rising bond market volatility does not automatically signal an imminent bear market. In each of these episodes, stocks continued advancing for weeks, months and, in some cases, more than a year after fixed-income investors first became concerned. The lesson is not that bond investors are always right about timing. It is that when bond markets and equity markets disagree, one of them is eventually forced to adjust.
Today, with market breadth near historic lows, leadership concentrated in a handful of AI-related stocks and bond market volatility rising sharply, investors would be wise to pay attention to what fixed-income markets may be signalling.
Higher yields create a challenge not only for governments but also for the very companies leading the AI boom. As borrowing costs rise, financing massive infrastructure projects becomes more expensive. What has been the market’s strongest tailwind could eventually become a significant headwind if capital costs continue moving higher.
Ironically, much of this pressure could have been avoided. Geopolitical developments earlier this year contributed to higher energy prices and renewed inflation concerns at precisely the wrong moment for an economy that was already showing signs of slowing outside of AI-related spending.
Today, what appears to be a healthy economy is becoming increasingly dependent on a narrow slice of activity tied to artificial intelligence, while many parts of the broader economy continue to soften. Consumer confidence, housing activity and portions of the manufacturing sector remain far less robust than headline market returns would suggest.
For Canadian investors, the implications are significant. A combination of higher U.S. bond yields and a stronger U.S. dollar continues to place pressure on the Canadian dollar. This leaves the Bank of Canada facing a difficult balancing act: maintain lower interest rates to support domestic growth and risk further currency weakness, or tighten policy to support the currency at the expense of economic activity. Not surprisingly, interest-rate-sensitive sectors such as utilities, infrastructure and telecommunications have struggled.
Against this backdrop, we at TriVest Wealth Counsel have modestly increased our defensive positioning. Recently, we implemented a zero-cost equity hedge covering approximately 7.5 per cent of our balanced fund, providing downside protection while preserving upside participation should markets continue to advance. We have also completed our annual tax-loss selling program ahead of the traditional November selling season.
The lesson is simple: when markets become dependent on a single narrative, investors should pay close attention to what is happening beneath the surface. Narrow leadership can persist far longer than many expect, but history suggests it rarely endures indefinitely. Eventually, fundamentals reassert themselves.
And when they do, the bond market often proves to have been telling the more important story all along.
Martin Pelletier, CFA, is the author of Investing Through the Storm and a senior portfolio manager at TriVest Wealth, a team that is part of Wellington-Altus Private Counsel Inc. TriVest provides discretionary risk-managed portfolios, investment audit/oversight and advanced tax, estate and wealth planning. The opinions expressed are not necessarily those of Wellington-Altus.
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