• Home
  • Latest
  • Fortune 500
  • Finance
  • Tech
  • Leadership
  • Lifestyle
  • Rankings
  • Multimedia
FinanceInvesting

The single, best way to tell whether stocks are worth it

Shawn Tully
By
Shawn Tully
Shawn Tully
Senior Editor-at-Large
Down Arrow Button Icon
Shawn Tully
By
Shawn Tully
Shawn Tully
Senior Editor-at-Large
Down Arrow Button Icon
September 30, 2014, 2:27 PM ET
Volatile Trading Day On Wall Street As Fears Over Euro Zone Continue
NEW YORK, NY - MAY 23: Traders work on the floor of the New York Stock Exchange May 23, 2012 in New York City. After a volatile trading day where European stocks saw record lows, the Dow Jones Industrial Average dipped as much as 191 points but ended just off 6.66 points at 12496.15. (Photo by Allison Joyce/Getty Images)Photo by Allison Joyce—Getty Images

Investors have come down with a case of the jitters, and for a good reason.

Since September 22, the Dow has careened through three days of 100 point-plus losses. The gigantic pop in the Alibaba IPO and the Chinese e-commerce phenomenon’s epic valuation have begun to stir fears that we’ve hit a market peak.

What’s worrying is that prices are displaying far greater faith in the future than the unimpressive fundamentals suggest is warranted. We’re living in a world of record-high corporate valuations and mediocre earnings growth.

To get the most accurate picture of the situation, let’s examine a metric that tells you when stocks are really a buy, and when they’re overly pricey. It’s called the Equity Risk Premium, or ERP, and it’s been lauded as the Holy Grail of corporate finance. The name may sound wonky, but for making money in stocks in the long-term, it’s the most practical measurement you’ll ever find.

The Equity Risk Premium is the extra return that investors demand for taking the additional risk of choosing stocks over far safer Treasury bonds. The higher the ERP, the bigger the potential future returns. Risk premiums ballooned, for example, in the panic of 2009, and folks who bought then profited handsomely. By contrast, when the ERP is below average, gains on equities tend to be weak or non-existent in the years to come.

What’s misleading is that the real, sustainable ERP has been disguised by a temporary phenomenon: unsustainably low interest rates. But it’s no great challenge to unmask an adjusted, realistic ERP from the illusory, official one. And as we’ll see, that slender figure is cause for alarm.

The ERP is simply the expected return on equities minus the inflation-adjusted yield on 10-year treasuries—that’s the extra cushion, or margin for error, you’d expect for braving equities. The best measure of the expected return is the earnings yield on the CAPE, or Cyclically Adjusted Price-Earnings Ratio, developed by economist Robert Shiller. The CAPE is the most reliable yardstick for returns since it adjusts for temporary, highly misleading swings in profits. Right now, the E/P (earnings to price ratio) on the CAPE stands at 3.8%. That’s the inverse of the Shiller price-to-earnings ratio of 26.3.

So the expected return on stocks is now 3.8%, adjusted for inflation. The second step consists of subtracting the real rate on the 10-year Treasury to get the ERP. The long bond is now yielding around 2.5%, and inflation is running at around 2%. So the real yield is a mere 0.5%.

Hence, the ERP is our 3.8% expected return minus 0.5%, or 3.3%. By historical standards, that’s a good figure. It’s an encouraging signal for the bulls, even the responsible ones. They can argue that the expected return of 3.8% plus inflation of 2%, or 5.8% in total, isn’t great, but clocks the yields on the long bond. So why not buy stocks?

Even the optimists, however, acknowledge that interest rates need to rise. Today, the incredibly low 0.5% real yield has created a mirage in the form of a superficially strong ERP. Things always go back to normal, so consider the results when the Fed unshackles interest rates and lets them swing back to their historic norms. Over time, real rates hover in the 2% range. What will happen when they rise from today’s level of 0.5% to 2%, bringing the yield on the 10-year Treasury bond to 4% (the total of the 2% real yield plus a 2% premium for future inflation)?

Now, we can re-calculate the ERP to eliminate the funhouse mirror effect of artificially low interest rates. The expected return of 3.8%, minus the reasonable, future real rate of 2%, leaves an under-nourished ERP of just 1.8%.

That’s not enough to justify investing in stocks. Let’s assume investors still demand a spread over bonds of 3.3 points, matching what they’re supposed to be getting today. Now they’ll require future returns not of 5.8%, but 7.3% (that’s the real rate of 2% plus the ERP of 3.3% plus inflation of 2%).

Restoring the ERP to attractive levels will require a sharp drop in company valuations. The Shiller PE would need to fall from 26.3 to 18.9, causing stock prices to drop by 28%. The S&P would look alluring again at around 1,425. Watching the ERP is all about what really matters in investing: ensuring you are well paid for risk. So follow the sovereign of all market metrics.

About the Author
Shawn Tully
By Shawn TullySenior Editor-at-Large

Shawn Tully is a senior editor-at-large at Fortune, covering the biggest trends in business, aviation, politics, and leadership.

See full bioRight Arrow Button Icon

Latest in Finance

Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025

Most Popular

Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Fortune Secondary Logo
Rankings
  • 100 Best Companies
  • Fortune 500
  • Global 500
  • Fortune 500 Europe
  • Most Powerful Women
  • Future 50
  • World’s Most Admired Companies
  • See All Rankings
Sections
  • Finance
  • Fortune Crypto
  • Features
  • Leadership
  • Health
  • Commentary
  • Success
  • Retail
  • Mpw
  • Tech
  • Lifestyle
  • CEO Initiative
  • Asia
  • Politics
  • Conferences
  • Europe
  • Newsletters
  • Personal Finance
  • Environment
  • Magazine
  • Education
Customer Support
  • Frequently Asked Questions
  • Customer Service Portal
  • Privacy Policy
  • Terms Of Use
  • Single Issues For Purchase
  • International Print
Commercial Services
  • Advertising
  • Fortune Brand Studio
  • Fortune Analytics
  • Fortune Conferences
  • Business Development
  • Group Subscriptions
About Us
  • About Us
  • Editorial Calendar
  • Press Center
  • Work At Fortune
  • Diversity And Inclusion
  • Terms And Conditions
  • Site Map
  • About Us
  • Editorial Calendar
  • Press Center
  • Work At Fortune
  • Diversity And Inclusion
  • Terms And Conditions
  • Site Map
  • Facebook icon
  • Twitter icon
  • LinkedIn icon
  • Instagram icon
  • Pinterest icon

Latest in Finance

middle
EconomyWealth
Turns out the American middle class didn’t die. It got richer—and felt poorer
By Nick LichtenbergApril 12, 2026
27 minutes ago
boomer
CommentaryLongevity
America is not ready for its own longevity crisis — and 2026 is the wake-up call
By Aimee DeCamillo and Diane TyApril 12, 2026
57 minutes ago
Donald Trump stands behind a podium while pointing a finger in front of him.
EconomyTariffs
‘People are trying to be creative’: Tariff-battered American companies are so cash-starved they are using refund claims as collateral for loans
By Sasha RogelbergApril 12, 2026
3 hours ago
Former Citgo Petroleum interim CEO José Pereira was one of the 'Citgo Six' political prisoners held captive in Venezuela for nearly five years.
EnergyVenezuela
Former ‘Citgo 6’ political prisoner sees ‘karma’ in Maduro ouster, but Venezuelan oil won’t rebound until there’s true regime change
By Jordan BlumApril 12, 2026
4 hours ago
JD Vance leaves Pakistan after marathon talks with Iran end without a deal as Tehran refuses U.S. demand not to develop nuclear weapons
PoliticsIran
JD Vance leaves Pakistan after marathon talks with Iran end without a deal as Tehran refuses U.S. demand not to develop nuclear weapons
By Munir Ahmed, E. Eduardo Castillo, Samy Magdy, Cara Anna, Ben Finley, Collin Binkley and The Associated PressApril 11, 2026
8 hours ago
‘This is the last warning.’ Iran threatens U.S. warships after they throw down the gauntlet for winner-take-all Strait of Hormuz
PoliticsIran
‘This is the last warning.’ Iran threatens U.S. warships after they throw down the gauntlet for winner-take-all Strait of Hormuz
By Jason MaApril 11, 2026
13 hours ago

Most Popular

'This is the last warning.' Iran threatens U.S. warships after they throw down the gauntlet for winner-take-all Strait of Hormuz
Politics
'This is the last warning.' Iran threatens U.S. warships after they throw down the gauntlet for winner-take-all Strait of Hormuz
By Fortune EditorsApril 11, 2026
13 hours ago
Palantir CEO says AI ‘will destroy’ humanities jobs but there will be ‘more than enough jobs’ for people with vocational training
Future of Work
Palantir CEO says AI ‘will destroy’ humanities jobs but there will be ‘more than enough jobs’ for people with vocational training
By Fortune EditorsApril 11, 2026
1 day ago
The 'affordability economy' has created a housing market nobody predicted: Prices collapsing in the Sun Belt, soaring in the Rust Belt
Real Estate
The 'affordability economy' has created a housing market nobody predicted: Prices collapsing in the Sun Belt, soaring in the Rust Belt
By Fortune EditorsApril 11, 2026
1 day ago
Warren Buffett says 'accumulating great amounts of money' doesn’t achieve greatness—He still lives in a $31,500 Nebraska home and clipped coupons
Success
Warren Buffett says 'accumulating great amounts of money' doesn’t achieve greatness—He still lives in a $31,500 Nebraska home and clipped coupons
By Fortune EditorsApril 11, 2026
1 day ago
Navy tests Hormuz blockade as expert says U.S. military prepares for round 2 and could degrade Iran's hold over the strait to a 'manageable level'
Politics
Navy tests Hormuz blockade as expert says U.S. military prepares for round 2 and could degrade Iran's hold over the strait to a 'manageable level'
By Fortune EditorsApril 11, 2026
18 hours ago
Scottie Scheffler joined Tiger Woods and Rory McIlroy in golf's $100M club—and donated his entire Ryder Cup stipend to charity
Success
Scottie Scheffler joined Tiger Woods and Rory McIlroy in golf's $100M club—and donated his entire Ryder Cup stipend to charity
By Fortune EditorsApril 10, 2026
2 days ago

© 2026 Fortune Media IP Limited. All Rights Reserved. Use of this site constitutes acceptance of our Terms of Use and Privacy Policy | CA Notice at Collection and Privacy Notice | Do Not Sell/Share My Personal Information
FORTUNE is a trademark of Fortune Media IP Limited, registered in the U.S. and other countries. FORTUNE may receive compensation for some links to products and services on this website. Offers may be subject to change without notice.