The US Economy Is Vulnerable to a Stock Correction, KPGM Economist Warns

KPMG chief economist Diane Swonk has a warning that should make anyone with a retirement account or a mortgage pay attention: the U.S. economy is particularly vulnerable to a stock market correction right now, and the reason has everything to do with who has been driving the recovery.

The short version is that the economic expansion of the past two years has been disproportionately powered by high earners — the top 20% of households making more than $175,000 annually. This cohort accounts for nearly 60% of all consumer spending, according to research from Moody's Analytics. Their spending has held up despite inflation because their wealth, largely tied to the stock market, has been growing faster than prices. The S&P 500 has been hovering near record highs, and every new all-time high reinforces the "wealth effect" that makes affluent Americans feel comfortable spending.

But Swonk, speaking to Business Insider, articulated the core risk: "We have built up a mountain of wealth that is highly concentrated." When wealth is concentrated at the top, the economy's resilience becomes dependent on that wealth persisting. And that wealth is overwhelmingly tied to financial assets — stocks, stock options, private equity holdings, and venture capital portfolios — that can lose value rapidly and without warning.

Moody's chief economist Mark Zandi reinforces the point. The K-shaped economy, where high earners thrive while the bottom 80% fall further behind, is "alive and well," Zandi says. Spending from the bottom 80% of earners has fallen short of inflation, meaning they're effectively getting poorer even as headline GDP numbers look robust. This divergence explains the persistent disconnect between strong economic data and bleak consumer sentiment surveys. As Swonk puts it, the concentration of wealth "has left us with an economy that looks better in the aggregate than it feels to most Americans."

The vulnerability Swonk identifies is structural, not cyclical. A standard recession hits broadly — everyone loses, but the pain is distributed. A market correction in a K-shaped economy would hit disproportionately at the top, where the spending power is concentrated. If the affluent suddenly feel less affluent — if their stock portfolios drop 15-20% and their company's stock options go underwater — they pull back on spending. And since that cohort accounts for 60% of consumer spending, even a modest pullback cascades through the entire economy.

The AI trade is central to this vulnerability. Much of the market's recent gains have been concentrated in a handful of mega-cap tech stocks — Nvidia, Microsoft, Alphabet, Amazon, Meta — that are seen as the primary beneficiaries of the artificial intelligence boom. These stocks have driven the major indices to record highs, inflating the wealth of the same affluent cohort that Swonk identifies as the economy's main pillar. But the AI trade also introduces concentration risk. If AI sentiment shifts — if revenue growth fails to justify the valuations, or if a major AI project stumbles — the market correction could be sharp and concentrated precisely where the economy is most dependent.

There are also political and regulatory risks. The Justice Department and Federal Trade Commission have been circling the big tech platforms for years. Antitrust action against a major AI company could trigger a broader selloff. Meanwhile, the Federal Reserve's evolving stance on interest rates under new Chair Kevin Warsh adds another layer of uncertainty. A hawkish surprise — signaling that rate cuts are further away than the market expects — could spook the growth stocks that have driven the rally.

Swonk is careful not to predict a crash. The "unknown," as she puts it, is whether the cushion of accumulated wealth is large enough to absorb a correction without breaking the economy's momentum. That's what keeps her up at night. The honest answer is that no one knows. We've never had an economy where 60% of spending comes from the top quintile, and we've never stress-tested that structure against a significant market downturn.

What This Means For You: If you're in the bottom 80% of earners, the K-shaped economy isn't news — you've been living it. Your costs have risen faster than your income, and the headline economic numbers have felt disconnected from your daily reality. A market correction wouldn't directly hurt you the way it would hurt the top 20%, but the indirect effects could be severe: job losses in sectors dependent on affluent spending, reduced investment in your community, and a potential credit tightening that makes it harder to get loans. If you're in the top 20%, the message is simpler: make sure your financial plan accounts for a 20-30% stock market decline without forcing you to sell. The wealth effect works both ways — it amplifies the highs and deepens the lows. And if you're anywhere on the income spectrum, start paying attention to where your retirement funds are concentrated. Index funds that track the S&P 500 are heavily weighted toward the same mega-cap tech stocks that are driving this entire vulnerability.