Which of the AI bubble indicators are we already seeing? Should we be concerned?

Bubble in AI

We’re already seeing multiple classic bubble indicators: extreme valuations (Buffett Indicator, Shiller CAPE), record retail participation, AI-driven hype, and surging margin debt—all pointing to elevated risk.

Key Bubble Indicators Already Present

📈 Buffett Indicator (Market Cap to GDP) This ratio is at historically high levels, suggesting stocks are significantly overvalued relative to the economy. Warren Buffett himself has warned investors may be “playing with fire”.

📊 Shiller CAPE Ratio Another respected valuation metric, the cyclically adjusted price-to-earnings ratio, is also elevated—indicating unsustainable earnings multiples and potential for correction.

🧠 AI-driven speculation The rally is heavily concentrated in AI and tech stocks, with some analysts calling it a “toxic calm” before a crash. Search volume for ‘AI bubble‘ is at record highs, and billionaire Paul Tudor Jones has issued warnings.

📉 Retail investor frenzy A record 62% of Americans now own stocks, with $51 trillion at stake. This surge in retail participation is reminiscent of past bubbles, where optimism outpaces caution.

📌 New market highs The Nasdaq, S&P 500, and Dow have hit dozens of new highs in recent months. While bullish on the surface, this pace of gains often precedes sharp reversals.

💸 Margin debt and risk appetite Risk-taking is accelerating, with margin debt climbing and speculative behavior increasing. Analysts note this as a historically bad sign when paired with euphoric sentiment.

What’s Not Yet Peaking (But Worth Watching)

IPO and SPAC volume: While not at 2021 levels, any surge here could signal speculative excess.

Corporate earnings vs. valuations: Some firms still show strong earnings, but the disconnect is widening.

Narrative dominance: AI optimism is strong, but hasn’t fully eclipsed fundamentals—yet.

How far away are we from the AI bubble popping?

Will it deflate slowly or burst?

Buffett Indicator surges past 200% – raising alarm bells on market valuation

Warren Buffett

The so-called ‘Buffett Indicator’—a stock market valuation metric championed by Warren Buffett—has surged past 200%, reigniting concerns that equities may be dangerously overvalued.

The ratio, which compares the total market capitalisation of U.S. stocks to the country’s gross domestic product (GDP), now sits well above the threshold Buffett once described as “playing with fire”.

Historically, the Buffett Indicator has served as a broad gauge of whether the market is trading at a premium or discount to the underlying economy.

100%

A reading of 100% suggests that the market is fairly valued. But when the ratio climbs significantly above that level, it implies that investor optimism may be outpacing economic fundamentals.

200%

At over 200%, the current reading suggests that the market is valued at more than twice the size of the U.S. economy. This level is not only unprecedented—it’s also well above the peak seen during the dot-com bubble, which ended in a dramatic crash in the early 2000s.

Buffett himself has warned in the past that when the indicator reaches extreme levels, it should serve as a ‘very strong warning signal’. While he has not commented on the current spike, the metric’s ascent has prompted renewed scrutiny from analysts and investors alike.

Some argue that the indicator may be distorted by structural changes in the economy, such as the rise of intangible assets and global revenue streams that aren’t captured by GDP alone.

Others point to low interest rates and persistent liquidity as reasons why valuations have remained elevated.

Do not ignore the warning

Still, the psychological impact of the 200% mark is hard to ignore. It suggests that investors may be pricing in perfection—expecting strong earnings growth, low inflation, and continued central bank support. Any deviation from this ideal scenario could trigger a sharp revaluation.

For long-term investors, the Buffett Indicator’s warning may not signal an immediate crash, but it does suggest caution. Diversification, disciplined risk management, and a clear understanding of valuation metrics are more important than ever.

As markets continue to defy gravity, the Buffett Indicator stands as a quiet sentinel—reminding investors that even the most exuberant rallies are tethered to economic reality. Whether this is a moment of irrational exuberance or a new normal remains to be seen.

But as Buffett once said, ‘The stock market is a device for transferring money from the impatient to the patient’.

It’s just a matter of ‘time’

🔍 How It Works

Formula:

Buffett Indicator=Total MarketCap/GDP

Interpretation:

Below 100%: Market may be undervalued

100%–135%: Fairly valued

Above 135%: Overvalued

Above 200%: Historically considered ‘playing with fire’, according to Buffett himself

🚨 Current Status (as of late September 2025)

The Buffett Indicator has surged to 218%, breaking records set during the Dotcom bubble and the COVID-era rally.

This extreme level suggests that equity values are growing much faster than the economy, raising concerns about a potential market bubble.

The surge is largely driven by mega-cap tech firms investing heavily in AI, which has inflated valuations.

🧠 Why It Matters

Buffett once called this “probably the best single measure of where valuations stand at any given moment.”

While some argue the metric may be outdated due to shifts in the economy (e.g., rise of intangible assets like software and data), it still serves as a powerful warning signal when valuations soar far above GDP.

Berkshire Hathaway at $1 trillion market cap – the first U.S. non tech company to do so

$1 trillion club

Warren Buffett’s Berkshire Hathaway achieved a $1 trillion market capitalisation on Wednesday 28th August 2024, becoming the first non-technology company in the U.S. to reach this business accolade.

The shares of the conglomerate, headquartered in Omaha, Nebraska, have surged over 28% in 2024, outperforming the S&P 500’s 18% increase. This major achievement came just two days before Buffett, often referred to as the ‘Oracle of Omaha,’ was due to celebrate his 94th birthday.

On Wednesday, the company’s shares rose by 0.8% to $696,502.02, surpassing the $1 trillion mark, as reported. The shares soared even further in the subsequent trading session.

One year chart for Berkshire Hathaway

One year chart for Berkshire Hathaway

The milestone serves as a testament to the firm’s financial robustness and the value of its franchise. It is particularly noteworthy given that Berkshire stands as one of the few remaining conglomerates today.

Buffett, serving as chairman and CEO, assumed command of Berkshire, a floundering textile enterprise, in the 1960s. He revolutionised the firm into a vast conglomerate covering insurance, railroads, retail, manufacturing, and energy sectors, boasting an unparalleled balance sheet and a formidable cash reserve.

Unlike the six other companies in the trillion-dollar club (Apple, Nvidia, Microsoft, Alphabet, Amazon and Meta), Berkshire is known for its old-economy focus as the owner of: BNSF RailwayGeico Insurance and Dairy Queen. (Although its sizable Apple position has helped drive recent gains.)

What evidence is there that the U.S. stock market is overvalued right now?

U.S. overvalued stocks

High Price-to-Earnings (P/E) ratio

The P/E ratio of the market is a common measure of valuation. Currently, the P/E ratio is significantly higher than historical averages, indicating that stocks are priced much higher relative to their earnings.

Rapid price increases without corresponding earnings growth

When stock prices rise rapidly without a corresponding increase in earnings, it often signals overvaluation. This has been observed recently, especially with some of the major tech stocks.

Comparison to historical market tops

The current market valuations are almost as high as they were at the peak in January 2022, which was followed by a significant correction.

Buffet valuation metric

Metrics like the Buffett Indicator (market capitalisation to GDP ratio) and Tobin’s Q (market value of assets divided by replacement cost) also suggest that the market is overvalued.

While these indicators point towards overvaluation, it’s important to note that markets can remain overvalued for extended periods, and other factors like strong earnings growth can sustain high valuations for some time

U.S. stock market could be overvalued by as much as 68%

The U.S. stock market, according to some analysts suggests that the current market appears to be overvalued by around 68%.

By comparison, at the peak of the Dot-com bubble, on 24th March 2000, the market was 89.5% overvalued. When the market bottomed out 2.5 years later, it had dropped around 50% from its previous all-time high and was undervalued by nearly 21%.

The fact that the market currently appears overvalued does not necessarily mean it will correct any time soon. The forces pulling the market toward the long-run equilibrium are relatively weak and allow the market to stay over or undervalued for extended periods of time.

From 1954 to 1970, the market stayed continuously overvalued for over some 15 years, and from 1973 until 1987, it stayed undervalued for about 14 years.

The analysis clearly suggests that U.S. stocks are overvalued – but that doesn’t necessarily mean a downturn any time soon – but it will, in time, adjust.

Common investing mistakes to avoid

Wise stock selection

Avoiding common investing and trading pitfalls is crucial. Here are some typical investing errors you should try to avoid.

Warren Buffett wisely cautions against investing in businesses that are not well understood. It is crucial to have a deep understanding of the company, its market sector, the broader industry, and its financial stability before committing to an investment.

Understand your investment

Take time to research whether it be a company, fund, unit trust or savings account. Make sure you understand what you are doing. Not understanding the investment is a massive failing.

Love the company, but resist falling in love with it. An emotional attachment to a specific stock can obscure your judgement. Keep in mind that investing should be a process of making rational decisions based on data, not on personal emotions.

Patience

Successful investing demands patience. Don’t anticipate immediate results; give your investments the necessary time to mature. Resist the urge to frequently check the markets and make hasty uninformed decisions.

Investment turnover

Excessive trading, known as churning, can result in significant transaction fees and tax consequences. It is advisable to adopt a long-term investment strategy and minimize superfluous trades.

Attempting to time the market

Consistently timing the market is a difficult task. Instead, the emphasis should be on the duration of market involvement. Steady contributions and maintaining investments yield benefits in the long-term.

Getting even

Clinging to underperforming investments with the hope of just breaking even can be harmful. It’s crucial to assess each investment on its own merits and be prepared to take losses when needed. Run the winners!

Diversify

Investing all your funds in a single stock or asset class heightens the risk. Mitigate this by diversifying your investments across various asset types, industries, sectors and regions.

Cut emotions

Fear and greed often result in unwise decisions. It’s crucial to remain disciplined, adhere to your investment plan, and resist the urge to make hasty decisions driven by emotions.

You

Always maintain honesty with yourself when investing. Do not persuade yourself of anything other than the FACTS regarding your investment choices!

Keep in mind that investing is a journey where learning from mistakes is an integral part of the experience. By steering clear of these common pitfalls, you’ll set yourself up for greater long-term success.

Spread out your investments. Diversify. Aim for the long term. Remove emotion. Let the winners run. And doe your RESEARCH!

RESEARCH! RESEARCH! RESEARCH!

Buffet Indicator & U.S. Stock Market

Wise Owl

The Buffet Indicator is a valuation multiple used to assess how expensive or cheap the aggregate stock market is at a given point in time. It was proposed by investor Warren Buffett in 2001, who called it ‘probably the best single measure of where valuations stand at any given moment‘ . It compares the total value of all publicly traded securities in the U.S. to the U.S. GDP .

The current value of the Buffet Indicator is 181%, (July 2023) – which suggests that the U.S. stock market is reportedly worth $48.37 trillion, while the U.S. GDP is $26.74 trillion

This ratio is 50.50% above the historical trend line, suggesting that the stock market is overvalued relative to GDP. Buffett warned that if the ratio approaches 200%, ‘you are playing with fire‘.

Buffett Indicator: $48.85T ÷ $26.91T = 182%

Does it Matter?

The Buffett Indicator expresses the value of the U.S. stock market in terms of the size of the U.S. economy. If the stock market value is growing much faster than the actual economy, then it may be in a bubble.

Buffet Indicator Movement Above and Below Trend Line