Overnight, the 10-year US Treasury yield hit a 24-year high this week, briefly breaking above 5.36% intraday before closing at 5.276%. Against this backdrop, a divided picture has emerged in the US equity market: the S&P 500 remains near its historic highs, yet internal valuation compression, sector divergence, and extreme market concentration are evolving in tandem.

The S&P 500's current forward price-to-earnings ratio sits at roughly 19.3 times, down from 22.2 times at the start of the year. The magnitude of the valuation compression is considerable, yet the index itself has not suffered a major decline 鈥?the reason being that earnings expectations have strengthened in parallel, partially offsetting the impact of multiple contraction. "Higher rates have already delivered a huge hit to the stock market. The P/E has come down three notches. That impact is very direct, but it has been masked because earnings have been so outstanding," said Bob Doll, Chief Investment Officer at Crossmark Global Investments.

"This is basic Finance 101 鈥?the higher the rates, the less stocks are worth," said Mark Hackett, Chief Market Strategist at Nationwide Investment Management.

Small Caps Hit First, Mag 7 Becomes a Safe Haven

Meanwhile, small-cap stocks are absorbing a more direct blow. The Russell 2000 has fallen 9% from its record closing high set less than two months ago, closing at 2,793.20 on Wednesday, just one step away from formally entering technical correction territory (a 10% decline from its peak).

Keith Lerner, Chief Investment Officer at Truist Advisory Services, noted: "The 'number one and most important factor' behind the recent decline in small caps is the rise in long-term US Treasury yields. Rising rates are biting 鈥?it's just that the tech sector has masked it."

Small caps' vulnerability has structural causes. Lerner explained: "Small caps are more sensitive to interest rates; they carry more debt, and a higher proportion of that debt is floating-rate compared with their large-cap peers."

Steve Sosnick, Chief Strategist at Interactive Brokers, also said: "A 2.2% second-quarter GDP growth rate does not necessarily lift all boats with the tide. Uneven economic growth, combined with a sharp rebound in interest rates, makes for a difficult environment for small caps."

Notably, even tech-oriented small caps have not been spared 鈥?the Invesco S&P SmallCap Information Technology ETF (PSCT) has fallen 10.4% since its June 30 high.

Extreme Market Concentration: Four Companies Carry the Entire Index

The resilience of the large-cap index stems largely from the contribution of a very small number of companies.

According to Citadel Securities research data, Microsoft, Nvidia, Apple, and Meta together contributed roughly 300 points to the S&P 500 in the third quarter, more than three times the index's total gain over the same period; the other 496 companies collectively dragged the index down by 150 points.

Scott Rubner of Citadel wrote in a note to clients: "The stock market is not the economy, and it is becoming increasingly evident that the S&P 500 does not represent ordinary stocks either."

This concentration has approached historical extremes on multiple measures. The Dow Jones Industrial Average has fallen 4.2% over the past month, while the Nasdaq has risen nearly 4% over the same period 鈥?a divergence that vividly illustrates this bifurcation.

Bonds and Stocks Are Pricing 'Different Worlds'

Henry Allen, macro strategist at Deutsche Bank, raised a deeper warning in a recent report: the bond market and the stock market are currently pricing "fundamentally different macro regimes."

The bond market has begun to reflect higher inflation risk, greater fiscal risk, and expectations of more restrictive policy rates, with yields rising to multi-year highs in many parts of the world. But the stock market has largely ignored this 鈥?the S&P 500 closed last Friday less than 1% below its all-time high.

Allen pointed out that this divergence is "unlikely to persist." He wrote: "We are pricing the symptoms of the new regime (such as yields at multi-decade highs and widening sovereign bond spreads) without pricing its logical consequences (such as slowing growth and rising default risk) 鈥?and those consequences have historically manifested in the form of weaker risk assets."

Deutsche Bank listed the five most noteworthy market misalignments at present, with the core conclusion being: if financial stress does not subside quickly (as it did rapidly after the March 2023 Silicon Valley Bank episode), risk assets will face persistently rising pressure.

Earnings Season Becomes the Key Test

As the third-quarter earnings season kicks off in full next week 鈥?with Wall Street heavyweights such as JPMorgan Chase and Citigroup among the first to report 鈥?the bar for corporate earnings has been raised even higher.

Crossmark's Bob Doll expects higher interest rates to remain a headwind for stocks, especially for cyclical companies. He said: "If you have a little cash on hand, that's fine, because I don't think the stock market will rise in a straight line the way it did in the months before."

Since the S&P 500's prior closing high on August 13, 18 of its 25 industry sectors have declined, and the equal-weighted version of the S&P 500 has fallen 5%. Several sectors, including banking and real estate, have dropped more than 10%.

Whether earnings can continue to be "superb" will determine where this tug-of-war between valuations and yields ultimately leads.