The Papers that Changed Investing: The Cross Section of Expected Returns

For nearly 30 years, finance had one answer to every question about risk: beta. Market exposure. That single number supposedly explained why some stocks delivered higher returns than others.

Then two professors examined the actual data. What Eugene Fama and Kenneth French found didn't just challenge the prevailing wisdom. It demolished it.

Welcome to The Papers That Changed Investing.

Before Fama and French, the Capital Asset Pricing Model reigned supreme. Developed in the 1960s, CAPM said that beta — your exposure to market movements — was the only risk that mattered.

But cracks were showing. Small firms delivered returns too high for their betas. Value stocks — those with high book-to-market ratios — outperformed in ways beta couldn't predict.

Fama and French's insight: what if returns depend on multiple dimensions of risk, not just one?

They examined every NYSE, AMEX, and NASDAQ stock from 1963 to 1990 — testing which variables actually explained return differences across thousands of securities.

Their discovery shook the foundation of finance. Beta, on its own, showed a limited relationship with actual returns.

Instead, two easily measured variables mattered: size and value. Smaller companies earned higher returns than larger ones. Value companies — those trading cheaply relative to book value — earned higher returns than growth stocks.

Smaller, more distressed companies faced genuine economic headwinds. Investors demanded compensation for bearing those risks.

Fama and French didn't just theorize. They constructed a practical framework investors could actually use: the three-factor model.

The size factor, SMB — Small Minus Big — captures the premium smaller companies earn over larger ones. The value factor, HML — High Minus Low — captures the premium value stocks earn over growth stocks.

Together, these three factors explained up to 96 percent of the variation in diversified portfolio returns.

As Fama and French put it:

So what did Fama and French establish?

First: beta, when used alone, has little power to explain stock returns. The relationship between market beta and average returns was statistically flat during their entire 27-year sample period.

Second: size matters. Smaller companies consistently earn higher average returns than larger companies, even after accounting for their beta exposure. This is the size premium.

Third: value matters even more. Companies with high book-to-market ratios — typically distressed or out-of-favor firms — earn substantially higher returns than growth companies with low ratios. This is the value premium.

Here's why this matters for your investments today.

The practical insight? Long-term returns come from systematic exposure to specific risk factors — size and value — not from stock-picking or timing.

This research became the foundation for modern factor investing. It enabled portfolios that systematically tilt toward small and value companies, capturing premiums markets demand for those risks.

Dimensional Fund Advisors built their philosophy around these findings. Today, trillions are managed using factor strategies traced to this 1992 paper.

Eugene Fama won the Nobel Prize in 2013, in part for this work.

Understanding those dimensions separates wealth creation from guesswork.

Ready to build a portfolio that systematically captures the risk factors the research actually supports? Visit our website, IFA.com, to find out more.

Connect with an Advisor now!

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DISCLOSURES:

This video is for informational and educational purposes only and does not constitute investment advice or a recommendation to buy or sell any security. Investing involves risk, including the potential loss of principal. Past performance is not indicative of future results.

This video may include content generated or enhanced using artificial intelligence (AI).

The discussion of Eugene Fama, Kenneth French, and the Fama-French Three-Factor Model, and Dimensional Fund Advisors is intended to illustrate academic finance concepts and does not imply any endorsement of Index Fund Advisors, Inc. or its services.

Index Fund Advisors, Inc. is registered investment adviser. Additional information is available by reviewing IFA's ADV Brochure at https://www.adviserinfo.sec.gov/ or visiting www.ifa.com.