We Asked GMO’s Head of Asset Allocation Why This Bubble is Easy — But Investors Will Get it Wrong

We Asked GMO’s Head of Asset Allocation Why This Bubble is Easy — But Investors Will Get it Wrong

GMO's Ben Inker warns AI CapEx may be inflating corporate earnings before massive depreciation hits — making today's "reasonable" valuations a mirage that most investors will miss.

Jun 24, 2026 1:09:01 Difficulty: Intermediate Played

TL;DR

Ben Inker of GMO breaks down why today's AI-driven market is an "easy bubble" to navigate — investors can avoid the worst pain by shifting to international, value, and small-cap stocks without abandoning risk assets entirely. Unlike 2007, when every asset was overpriced, or 2021, when avoiding losses meant holding cash, non-US equities still offer decent expected returns. The most underappreciated risk: this may be an earnings bubble, not just a valuation bubble, as surging AI CapEx flatters corporate profits before depreciation arrives.

#AI infrastructure spending #earnings bubble #easy vs hard bubble #GMO seven-year forecast #international equity valuation #benchmark-free portfolio #private equity hidden risk #LBO analysis #capital cycle #circular financing #stock market supply #inelastic markets hypothesis #value investing #career risk in portfolio management #semiconductor cyclicality #AI bubble #GMO #asset allocation #international stocks #private equity #LBO #valuation #benchmark-free #risk premium #IPO supply #fiber optics #railroads #seven-year forecast #small-cap #career risk #Ben Inker

Ben Inker of GMO joins Excess Returns to break down whether the AI boom is an investment bubble, how it compares to 2000, 2007 and 2021, and why today's risk may be more about earnings than valuations. Topics include AI capital spending, market supply from IPOs, GMO's seven-year asset class forecasts, international stocks, benchmark-free allocation and what private equity investors may be missing.

Chapter list
  • Pre-roll advertisements for Google Chrome's Gemini AI feature and Microsoft's Windows 11 Unreal College Deal for students.

  • Ben Inker previews the episode's key ideas: earnings bubbles, historical comparisons to 2007 Europe, unprecedented US stock supply, and why understanding your return source matters.

  • Ben Inker defines investment bubbles and explains why some are easier to navigate than others. The internet bubble was easy; 2007 and 2021 were hard. Today's AI bubble is classified as easy because non-US risk assets still offer decent returns.

  • Ben Inker walks through GMO's risk-reward scatterplots from 2000, 2007, 2021, and today, explaining how the slope of the line reveals whether investors are being compensated for risk.

  • Advertisement for Indeed Sponsored Jobs offering a $75 sponsored job credit at indeed.com/podcast.

  • Ben Inker shares what GMO learned managing portfolios through the dot-com, GFC, and 2021 bubbles, including the perverse dynamic of clients firing cautious managers at market peaks.

  • Ben Inker contrasts today's market with the 2000 bubble, arguing that while fewer stocks trade at insane valuations, AI CapEx may be creating an earnings bubble by flattering profits before depreciation arrives.

  • Ben Inker contrasts today's market with the 2000 bubble, arguing that while fewer stocks trade at insane valuations, AI CapEx may be creating an earnings bubble by flattering profits before depreciation arrives.

  • Ben Inker applies commodity cycle logic to AI semiconductors, warning that SK Hynix and Micron may look cheap on trailing PE at the peak of the AI cycle but prove to be poor investments.

  • Ben Inker benchmarks AI data center spending at ~2.2% of US GDP and argues that every transformational technology has destroyed returns for its builders through the same capital cycle.

  • Discussion of how AI infrastructure financing has shifted from equity to debt, with detailed examples of the OpenAI-AMD and Anthropic-Alphabet-Broadcom deals as signs of circular finance.

  • Ben Inker warns that SpaceX, OpenAI, Anthropic and others could add 5-6% of US market cap as supply — historically the largest surge ever — with research suggesting 1% supply increases reduce returns by 7.5%.

  • Ben Inker warns that SpaceX, OpenAI, Anthropic and others could add 5-6% of US market cap as supply — historically the largest surge ever — with research suggesting 1% supply increases reduce returns by 7.5%.

  • Ben Inker explains GMO's 7-year return forecasts: income + growth + valuation mean reversion at 1/7 per year. Fair value depends on whether the world is in a low-rate or high-rate regime.

  • Ben Inker explains why GMO publishes two forecast scenarios: a 21x normalized PE fair value in a low-rate world vs. 16x in a high-rate world, with today's best guess being the low-rate scenario.

  • Discussion of why non-US equities, value stocks, and small caps globally look significantly more attractive than US equities, aided by dollar overvaluation giving currency tailwinds.

  • GMO's AI-assisted analysis of 700+ US LBOs reveals that private equity portfolios are overwhelmingly concentrated in small, lower-quality, highly leveraged companies — with only RJR Nabisco ever qualifying as a mega-cap buyout.

  • Ben Inker recommends going long S&P 100 / short Russell 2000, and biasing public portfolios toward quality to offset the hidden small-cap junk bet embedded in most private equity allocations.

  • Ben Inker argues that understanding the structural source of any investment return is the best defense against mistakes like buying tail-risk hedges that promise cash returns or chasing overvalued value stocks.

  • Post-roll advertisements for Palmolive Ultra dish soap, Botox for chronic migraine, and Vanta's AI-powered GRC compliance platform.

Earnings bubble
A market overvaluation driven by unsustainably elevated corporate earnings (rather than price multiples), so valuations appear normal even though profits will eventually mean-revert downward.
Capital cycle
The recurring process in which high returns attract excessive investment, leading to overcapacity, falling returns, and eventual bust; GMO uses it to explain why AI infrastructure may disappoint investors.
Inelastic markets hypothesis
Academic theory (discussed by Xavier Gabaix and Ralph Koijen) arguing that stock prices are far more sensitive to supply and demand flows than standard finance assumes.
ROIC
Return on Invested Capital; a measure of how efficiently a company generates profits from the money invested in it. Central to GMO's analysis of AI infrastructure economics.
Tracking error
The standard deviation of a portfolio's returns relative to its benchmark; a portfolio with high tracking error looks very different from the index, which creates client-retention risk.
Duration (financial)
A measure of sensitivity to changes in interest rates or discount rates; assets like long-term bonds, equities, and real estate have high duration and fall sharply when rates rise.
Hyperscaler
A company (e.g., Microsoft, Google, Amazon, Meta) that operates data centers at extreme scale; in this episode, discussed as the primary funders of AI infrastructure.
Ponzi finance
A funding structure where returns depend on continuously attracting new capital rather than underlying cash flows, identified by Hyman Minsky as a late-stage bubble characteristic.
LBO (Leveraged Buyout)
Acquisition of a company using a large proportion of borrowed money, with the target's assets and cash flows used as collateral; the subject of GMO's 700-deal historical analysis.
Benchmark-free portfolio
An investment strategy with no obligation to match an index, allowing the manager to own only assets with a positive standalone risk-reward rationale.
Merger arbitrage
A strategy of buying shares of announced acquisition targets to capture the spread between current price and deal price; GMO includes it as a liquid alternative in its benchmark-free portfolio.
Term premium
The extra return investors demand for holding a long-term bond over rolling short-term instruments; GMO estimates this at roughly 100 basis points.
Equity risk premium
The extra return investors require to hold equities over the risk-free rate; GMO assumes approximately 4.5% over cash for stocks.
Bayesian adjustment
Updating a prior probability estimate with new evidence; GMO applies this to bubble forecasts to account for the possibility that a bubble persists longer than expected.
Supercycle
An extended commodity or capital cycle driven by demand growth so large it persistently outpaces supply; used in the episode to describe iron ore 2005-2012 as a possible AI analogy.
Writ large
On a larger or more general scale; used by Ben Inker to say the bubble exists across US equities broadly, not just in a narrow AI sector.
Skew
Asymmetry in a distribution; used to describe how LBO targets are disproportionately concentrated in small-cap companies rather than evenly distributed across the market-cap spectrum.

Chapter 2 · 00:58

Why Ben Inker thinks the AI bubble may be easier to navigate

Ben Inker previews the episode's key ideas: earnings bubbles, historical comparisons to 2007 Europe, unprecedented US stock supply, and why understanding your return source matters.

Chapter 3 · 02:43

What makes a bubble easy or hard for investors

Ben Inker defines investment bubbles and explains why some are easier to navigate than others. The internet bubble was easy; 2007 and 2021 were hard. Today's AI bubble is classified as easy because non-US risk assets still offer decent returns.

Chapter 4 · 08:12

Comparing risk and return in 2000, 2007, 2021 and today

Ben Inker walks through GMO's risk-reward scatterplots from 2000, 2007, 2021, and today, explaining how the slope of the line reveals whether investors are being compensated for risk.

Chapter 5 · 14:42

Why optimizers and real clients see risk differently

Advertisement for Indeed Sponsored Jobs offering a $75 sponsored job credit at indeed.com/podcast.

Chapter 6 · 17:02

What GMO learned from managing through past bubbles

Ben Inker shares what GMO learned managing portfolios through the dot-com, GFC, and 2021 bubbles, including the perverse dynamic of clients firing cautious managers at market peaks.

Chapter 7 · 19:08

How today compares to the 2000 internet bubble

Ben Inker contrasts today's market with the 2000 bubble, arguing that while fewer stocks trade at insane valuations, AI CapEx may be creating an earnings bubble by flattering profits before depreciation arrives.

Chapter 8 · 20:00

Why this may be an earnings bubble

Ben Inker contrasts today's market with the 2000 bubble, arguing that while fewer stocks trade at insane valuations, AI CapEx may be creating an earnings bubble by flattering profits before depreciation arrives.

Chapter 9 · 23:34

Semiconductors, memory makers and the capital cycle

Ben Inker applies commodity cycle logic to AI semiconductors, warning that SK Hynix and Micron may look cheap on trailing PE at the peak of the AI cycle but prove to be poor investments.

Chapter 10 · 25:00

How AI CapEx compares to railroads, electricity and fiber optics

Ben Inker benchmarks AI data center spending at ~2.2% of US GDP and argues that every transformational technology has destroyed returns for its builders through the same capital cycle.

Chapter 11 · 29:33

Debt, circular financing and strange AI deals

Discussion of how AI infrastructure financing has shifted from equity to debt, with detailed examples of the OpenAI-AMD and Anthropic-Alphabet-Broadcom deals as signs of circular finance.

Chapter 12 · 34:32

Why massive stock issuance could challenge the market

Ben Inker warns that SpaceX, OpenAI, Anthropic and others could add 5-6% of US market cap as supply — historically the largest surge ever — with research suggesting 1% supply increases reduce returns by 7.5%.

Chapter 13 · 40:00

How GMO builds seven-year asset class return forecasts

Ben Inker warns that SpaceX, OpenAI, Anthropic and others could add 5-6% of US market cap as supply — historically the largest surge ever — with research suggesting 1% supply increases reduce returns by 7.5%.

Chapter 14 · 41:40

Why interest rates change fair value for stocks and bonds

Ben Inker explains GMO's 7-year return forecasts: income + growth + valuation mean reversion at 1/7 per year. Fair value depends on whether the world is in a low-rate or high-rate regime.

Chapter 15 · 45:32

Why international, value and small-cap stocks look more attractive

Ben Inker explains why GMO publishes two forecast scenarios: a 21x normalized PE fair value in a low-rate world vs. 16x in a high-rate world, with today's best guess being the low-rate scenario.

Chapter 16 · 48:41

The case for a benchmark-free portfolio

Discussion of why non-US equities, value stocks, and small caps globally look significantly more attractive than US equities, aided by dollar overvaluation giving currency tailwinds.

Chapter 17 · 55:21

What 700 leveraged buyouts reveal about private equity

GMO's AI-assisted analysis of 700+ US LBOs reveals that private equity portfolios are overwhelmingly concentrated in small, lower-quality, highly leveraged companies — with only RJR Nabisco ever qualifying as a mega-cap buyout.

Chapter 18 · 1:02:00

How public portfolios can offset private equity risks

Ben Inker recommends going long S&P 100 / short Russell 2000, and biasing public portfolios toward quality to offset the hidden small-cap junk bet embedded in most private equity allocations.

Chapter 19 · 1:03:57

Why investors need to understand what they are paid for

Ben Inker argues that understanding the structural source of any investment return is the best defense against mistakes like buying tail-risk hedges that promise cash returns or chasing overvalued value stocks.

Chapter 20 · 1:08:27

Closing thoughts

Post-roll advertisements for Palmolive Ultra dish soap, Botox for chronic migraine, and Vanta's AI-powered GRC compliance platform.

No indexed bits in this chapter.

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This episode

Claims & Sources

1 / 15 cited (7%)

Factual claims made this episode, and whether a source was named.

As of late 2025, the slope of GMO's global risk-reward line was 0.4, falling to just 0.1 by mid-2026, but remaining ~0.4 when US equities are excluded.

Ben Inker no source cited

European corporate earnings rose 100% over the four years preceding the 2007-2008 financial crisis and have still not fully recovered to those peak levels on an index basis.

Ben Inker no source cited

2025 US data center capital spending is forecast at approximately $700 billion to $1.6 trillion, equal to about 2.2% of US GDP.

Ben Inker no source cited

The 19th-century US railroad buildout was approximately twice as large as today's AI data center buildout as a share of GDP.

Ben Inker no source cited

OpenAI was given AMD warrants worth roughly half the value of its GPU purchase, effectively receiving a 50% discount structured as equity compensation rather than a price reduction.

Ben Inker no source cited

Anthropic entered a deal to lease $36 billion worth of Alphabet TPUs, with Broadcom promising to buy back the TPUs if Anthropic defaults, giving the deal an investment-grade rating while keeping the contingent liability off Broadcom's balance sheet.

Ben Inker no source cited

Major AI hyperscalers have approximately doubled their debt ratios in the nine months prior to this episode recording.

Ben Inker no source cited

A 1% increase in US stock market supply is historically associated with a 7.5% worse return over the subsequent year.

Ben Inker Inelastic markets hypothesis paper (author not recalled)

SpaceX went public at a $1.8 trillion market capitalization but initially sold only $75 billion worth of shares, meaning most of the supply impact was deferred until lockups expire.

Ben Inker no source cited

The US stock market's two highest points of equity issuance supply in the last 50 years were 2000 and 2021 — both coinciding with major market peaks.

Ben Inker no source cited

GMO's fair value P/E for equities is approximately 21x normalized earnings in a low-rate environment (real cash return near zero) but falls to about 16x in a higher-rate environment.

Ben Inker no source cited

The concept that US stocks should trade at a persistent valuation premium to the rest of the world had no historical precedent as of 2010.

Ben Inker no source cited

In the entire history of US leveraged buyouts, only one deal involved a company that could be classified as mega-cap at the time: RJR Nabisco.

Ben Inker no source cited

For the average US endowment or foundation, roughly half of equity exposure comes from private equity, creating a large hidden concentration in small-cap, lower-quality companies.

Ben Inker no source cited

Over the past 40 years, the return on capital of large-cap US stocks has trended steadily upward while the return on capital of small-cap US stocks has been flat, creating an increasing quality wedge largely due to growing monopoly power among large caps.

Ben Inker no source cited

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