Concentration

Concentration
March 2026

Stock Market Concentration Has Surpassed Its 1930s Peak. Should Investors Worry?

Morningstar

Dan Lefkovitz

Research

8 Pages

Morningstar's Dan Lefkovitz looks at the top-heavy nature of today’s US stock market and how it compares to the past 100 years.

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Markets
March 2026

The Concentration Game

D.E. Shaw & Co.

Research

11 Pages

D.E. Shaw considers the impact of increased concentration on benchmark-relative equity portfolios, both in terms of overall risk and the potential to generate alpha.

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Concentration
January 2026

The extreme weight of AI in the S&P 500: Measures of concentration for market cap, returns, earnings, and capex

Apollo

Torsten Slok

Research

39 Pages

Apollo updated their chart book documenting the extreme AI concentration within the S&P 500’s market cap, returns, earnings and capex.

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Markets
October 2024

Updating our long-term return forecast for US equities to incorporate the current high level of market concentration

Goldman Sachs

David Kostin

Research

37 Pages

Goldman Sachs predicts that the S&P 500 will deliver an annualized nominal return of 3% over the next decade, placing it in the 7th percentile historically, with high market concentration significantly contributing to the lower forecast.

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Markets
August 2024

Investor Memo Q2 2024

Cornell Capital Group LLC

Research

12 Pages

Cornell Capital Group explains why they’re cautious about the market given various valuation and economic indicators.

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Markets
August 2024

CONCENTRATE! Is it like 2000 again?

GMO

Ty Cobb, Anthony Hene, Tom Hancock

Research

3 Pages

GMO compares the S&P 500 today to 2000, looking at market concentration, fundamentals and valuations.

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Markets
July 2024

Warning Signs

Lyrical Asset Management

Research

6 Pages

Lyrical flags the extreme performance gap between the S&P 500 and its equal-weighted counterpart as a historic red flag.

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Markets
June 2024

Stock Market Concentration

Morgan Stanley

Michael Mauboussin, Dan Callahan

Research

18 Pages

Michael Mauboussin looks at the concentration of global markets over the past 75 years and whether fundamental corporate performance supports the current increase in concentration.

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Markets
May 2024

200 Years of Market Concentration

Finaeon

Bryan Taylor

Research

13 Pages

GFD looks at the rise of concentration in the U.S. stock market, analyzing 235 years of data.

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