The new 60/40 in the AI era: not stocks and bonds, but AI and non-AI

```

The classic 60/40 equity-bond investment framework is being reshaped by a much more powerful force. The artificial intelligence (AI) theme has fully infiltrated the markets for stocks, corporate bonds, and venture capital, making it hard for investors—no matter what portfolio they hold—to avoid a heavy exposure to AI. Many are not even aware of this.

Torsten Slok, Chief Economist at Apollo Global Management, stated bluntly: "The new 60/40 is AI versus non-AI." He pointed out that of the top ten constituents in the S&P 500 Index, nine have core businesses deeply tied to AI, and these ten companies together account for around 40% of the index's total market capitalization. Meanwhile, in the venture capital arena, almost all net new investment in 2026 will flow to AI-related companies; and in the investment-grade bond market, bond issuance related to AI infrastructure already accounts for nearly half of all net new bond issuance.

Slok expects the investment-driven effect from the boom in AI data center construction to contribute about half of the United States’ projected real GDP growth of 2% in 2026. This means the rise and fall of AI will not only affect capital markets but also directly steer the direction of the macroeconomy.

AI Theme Has Systematically Infiltrated Multiple Asset Classes

The logic of the traditional 60/40 investment portfolio is based on the low correlation between stocks and bonds. However, Slok's analysis shows this logic faces a fundamental challenge in the age of AI—as this theme not only dominates the stock market but is simultaneously occupying the credit and private equity markets.

At the stock market level, nine of the top ten S&P 500 constituents—covering tech giants in chips, cloud computing, social media, and electric vehicles—are directly tied to AI business. This high concentration is not limited to the U.S.; it’s equally significant in emerging market stock indices, where a few South Korean semiconductor companies have become core weights in main emerging market indexes.

In the credit market, the large-scale bond issuances by companies like Oracle and SpaceX—despite lukewarm market responses—reflect the vast demand for AI infrastructure financing, which now accounts for nearly 50% of net new investment-grade bond issuance. In venture capital, almost all net new capital in 2026 will flow into the AI sector, with concentration at a historic high.

Productivity Dividend Yet to Be Realized

The biggest hidden risk of the AI investment wave lies in doubts about its technological effectiveness. Slok points out that so far, the companies truly profiting from AI are still mainly those producing chips and hardware needed for AI data centers.

He told MarketWatch: "This needs to deliver massive productivity gains, improved profit margins, and earnings growth—especially for the other 493 companies." He refers to the remaining 493 constituents of the S&P 500 excluding the ‘Magnificent Seven’. "The Magnificent Seven have performed outstandingly, no question, but the issue is whether this effect can eventually spread."

If AI's productivity promises are not fulfilled, a slowdown in data center investment will ripple down the supply chain throughout the economy. Meanwhile, since the wealth effect has played an increasingly important role in driving U.S. consumption since COVID-19, sharp asset price corrections will quickly affect the real economy.

Market Sentiment Remains Stable, Investors Have Not Fled

Despite these risks, current market performance suggests overall investor confidence remains unshaken. Rob Haworth, Senior Investment Strategist at Bank of America Wealth Management, notes that although momentum trading in AI-related assets has cooled since July, overall demand for AI assets remains robust.

Mark Hackett, Chief Market Strategist at Nationwide, says the S&P 500 has not seen a larger correction, indicating investors are now favoring structural rotation within the market, rather than a wholesale exit from equities. As of Wednesday’s close, the index was only about half a percentage point below its historic high since early June.

"Market sentiment shows demand is still there, credit spreads have not widened, and investors have not been scared off by large bond issuances," Haworth told MarketWatch. "This story remains strong."

Risk Warning and DisclaimerThe market is risky and investment should be approached with caution. This article does not provide personal investment advice, nor does it take into account the special investment objectives, financial situation, or needs of individual users. Users should consider if any opinions, views, or conclusions in this article are suitable for their particular situation. If you invest based on this, you are responsible for your own actions. ```