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

Trendingnow

1

Corporate America has been draining the world's water. Matt Damon's new campaign calls on Gap, Starbucks, and Amazon to help give it back

2

When SpaceX starts trading, some 'shareholders' will discover they own nothing at all

3

Analysts expected oil to surge above $200 but China has quietly kept prices half of that—and can’t for much longer

1

Corporate America has been draining the world's water. Matt Damon's new campaign calls on Gap, Starbucks, and Amazon to help give it back

2

When SpaceX starts trading, some 'shareholders' will discover they own nothing at all

3

Analysts expected oil to surge above $200 but China has quietly kept prices half of that—and can’t for much longer
InvestingMarkets

Back in the ’90s a Fed chief warned about ‘irrational exuberance’ in the markets. Stocks rose 105% over the next 4 years

Geoff Colvin
By
Geoff Colvin
Geoff Colvin
Senior Editor-at-Large
Down Arrow Button Icon
Geoff Colvin
By
Geoff Colvin
Geoff Colvin
Senior Editor-at-Large
Down Arrow Button Icon
September 30, 2025, 6:00 AM ET
Alan Greenspan famously warned of too high stock valuations in the 1990s.
Alan Greenspan famously warned of too high stock valuations in the 1990s.Steven Ferdman—Getty Images

Gen Zers are no doubt baffled by such recent headlines as “Fed Chair Powell just had his ‘irrational exuberance’ moment, Ed Yardeni says,” and “Did Jerome Powell Just Say ‘Irrational Exuberance’?” Those headlines refer to a long-ago event involving a previous Fed chair, dizzyingly high stock prices, and an eventual market crash. But beware: Some market soothsayers misinterpret that earlier episode, and getting it wrong could misguide today’s investors.

Recommended Video

The headlines were sparked by a Powell appearance where he was asked, after his speech, if today’s record-high stock prices affect Fed policy. He answered, “We do monitor that, but we’re not targeting any level of prices for particular financial assets. We don’t have a view that we know what the right price of any particular financial asset is.” It was classic circumspect Fed talk. Then he added, “We do look at overall financial conditions,” and he went further to note, “For example, equity prices are fairly highly valued.”  

Within minutes, the words “highly valued” were pinging through the financial world. The words’ importance was a bit fuzzy. Maybe the Fed would somehow engineer the markets downward, or, with its vast data, it might foresee a market decline.

Old-timers immediately saw the incident’s parallel with a speech Fed Chair Alan Greenspan gave in the 1990s. He mentioned the phrase “irrational exuberance”—in an abstract, what-if way—as a force that might push stock prices too high. No one heard it that way, however. His real message seemed clear: The most influential person in the world’s largest economy thought stock prices were too high.

Today that speech is widely seen as the setup for the historic market collapse of 2000 in which many hot new internet companies succumbed. Those recent headline writers are asking: Could Powell’s remark play the same role in a roaring market fueled by AI?

But that’s not the right question. Greenspan gave his speech in December 1996—almost four years before the market plunge. As he told Fortune years later, “If you had left the market when I gave my irrational exuberance speech, you would have missed another 80% of increase” in stock values. (Actually, it was closer to 100%.) As for Powell’s talk last Tuesday—despite the to-do, the S&P 500 has barely moved.

The lesson isn’t that investors tremble when Fed chairs talk about stocks. It’s that investor behavior is a compendium of many forces, and the Fed chief’s views don’t propel markets one way or another. That doesn’t mean Powell is wrong. His simple statement that stocks are highly valued is indisputable. Most measures are screaming that the S&P is insanely overpriced. The Shiller Cyclically Adjusted Price/Earnings ratio is the highest it has been since the dotcom peak. The price-to-sales ratio hit a new all-time high this week. The Buffett Indicator—ratio of the market’s capitalization to GDP—says stocks are highly overvalued, and Warren Buffett is holding an enormous cash cache because he can’t find bargains.

The truth is, nobody knows if the next crash is coming or when. Not even Fed chairs.

The Fortune 500 Innovation Forum will convene Fortune 500 executives, U.S. policy officials, top founders, and thought leaders to help define what’s next for the American economy, Nov. 16-17 in Detroit. Apply here.
About the Author
Geoff Colvin
By Geoff ColvinSenior Editor-at-Large
LinkedIn iconTwitter icon

Geoff Colvin is a senior editor-at-large at Fortune, covering leadership, globalization, wealth creation, the infotech revolution, and related issues.

See full bioRight Arrow Button Icon

Latest in Investing

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
  • World's Most Admired Companies
  • See All Rankings
  • Lists Calendar
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
  • Press Center
  • Work At Fortune
  • Terms And Conditions
  • Site Map
  • About Us
  • Press Center
  • Work At Fortune
  • Terms And Conditions
  • Site Map
  • Facebook icon
  • Twitter icon
  • LinkedIn icon
  • Instagram icon
  • Pinterest icon

Latest in Investing

owen
Investingbubble
The economist who said ‘no bubble’ just sounded the alarm: ‘The season of chaos is at hand’
By Nick LichtenbergJune 12, 2026
2 hours ago
Live updates from SpaceX IPO debut: SpaceX valuation now at over $2 trillion as stock climbs to $175 a share
InvestingSpaceX
Live updates from SpaceX IPO debut: SpaceX valuation now at over $2 trillion as stock climbs to $175 a share
By Catherina GioinoJune 12, 2026
4 hours ago
Current price of Bitcoin for June 12, 2026
Personal FinanceCryptocurrency
Current price of Bitcoin for June 12, 2026
By Joseph HostetlerJune 12, 2026
6 hours ago
Current price of Ethereum for June 12, 2026
Personal FinanceEthereum
Current price of Ethereum for June 12, 2026
By Joseph HostetlerJune 12, 2026
6 hours ago
Elon Musk
InvestingMarkets
When SpaceX starts trading, some ‘shareholders’ will discover they own nothing at all
By Jim EdwardsJune 12, 2026
9 hours ago
SpaceX’s IPO could be largest in history. Here’s how it compares to previous record-holders
Startups & VentureSpaceX
SpaceX’s IPO could be largest in history. Here’s how it compares to previous record-holders
By Mia OsmonbekovJune 12, 2026
12 hours ago

Most Popular

Corporate America has been draining the world's water. Matt Damon's new campaign calls on Gap, Starbucks, and Amazon to help give it back
Environment
Corporate America has been draining the world's water. Matt Damon's new campaign calls on Gap, Starbucks, and Amazon to help give it back
By Catherina GioinoJune 9, 2026
3 days ago
When SpaceX starts trading, some 'shareholders' will discover they own nothing at all
Investing
When SpaceX starts trading, some 'shareholders' will discover they own nothing at all
By Jim EdwardsJune 12, 2026
9 hours ago
Analysts expected oil to surge above $200 but China has quietly kept prices half of that—and can’t for much longer
Energy
Analysts expected oil to surge above $200 but China has quietly kept prices half of that—and can’t for much longer
By Sasha RogelbergJune 10, 2026
2 days ago
Current price of oil as of June 11, 2026
Personal Finance
Current price of oil as of June 11, 2026
By Joseph HostetlerJune 11, 2026
1 day ago
American taxpayers have spent $33 billion on sports stadiums. They got fewer seats—and higher prices
Success
American taxpayers have spent $33 billion on sports stadiums. They got fewer seats—and higher prices
By Catherina GioinoJune 11, 2026
1 day ago
Meet the SpaceX employees who are set to become multimillionaires thanks to its IPO: from execs to even welders
Success
Meet the SpaceX employees who are set to become multimillionaires thanks to its IPO: from execs to even welders
By Preston ForeJune 11, 2026
1 day 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.