Wednesday, September 30, 2026

Maybe Higher Interest Rates or High CAPE Ratios Will Not Derail AI Investment

The issue economists and financial analysts always face when attempting to assess the impact of higher interest rates on equity valuations in general or artificial intelligence in specific is that evaluations must be made on the assumption that “all other things remain equal,” which, of course, is rarely the case. Markets are dynamic, so, by definition, all else does not remain equal. 


Consider the expected impact of price-earnings ratios and higher real interest rates. 


The cyclically adjusted price-earnings ratio (CAPE) being at a historically-high level suggests lower returns from equity markets over the next decade or so and a possible "reversion to mean" for AI equity values.


But the high CAPE ratio does not mean artificial intelligence public equities are necessarily overvalued or in a “bubble.” It does mean that AI firms must grow into their valuations by continued high earnings growth. 


Observation

What CAPE suggests

U.S. equities are expensive relative to historical earnings

Strongly supported

Long-term expected real returns are probably lower than historical averages

Historically supported

AI stocks specifically are overvalued

Not established by CAPE

AI is a speculative bubble

CAPE cannot establish this

AI earnings expectations are unusually important to market valuation

Yes

A substantial earnings disappointment could have disproportionate market consequences

Yes

Higher interest rates would be especially consequential

Yes

AI productivity could eventually justify some of today's valuation

Possible

Today's valuation requires unusually strong future earnings growth

Yes


Is today's high CAPE a denominator problem or a numerator problem? The denominator problem happens if investors have simply bid up stocks too far relative to sustainable earnings.


The numerator problem happens if today's earnings substantially understate the future earnings power of the companies because AI is about to raise productivity and profits dramatically. Take your pick., 


The second possibility is the "this time is different" argument, an obvious red flag for most of us. Historically, that argument has sometimes been correct economically while still being wrong financially.


In the shorter term, investors will have to evaluate the likely impact of higher interest rates (the “real” rate being the thing that matters) on the AI ecosystem. 


The conventional wisdom is that higher real interest rates (nominal rate minus inflation) tend to slow economic growth. That should mean the AI ecosystem also grows more slowly, as higher financing costs reduce investment and therefore potentially future revenue growth.


Also, the present value of distant future cash flows falls when the discount rate rises. This can be particularly severe for AI companies because much of their expected value is based on future rather than current earnings.


Part of AI ecosystem

Likely effect of higher rates

Why

Hyperscaler AI capex

Moderate slowdown

Higher cost of capital raises the hurdle rate for marginal data centers, GPUs and power projects. But Microsoft, Alphabet, Amazon and Meta have enormous cash flows and strategic reasons to keep investing.

Frontier-model companies

Moderate-to-large pressure

Companies with large compute bills and limited current profits become more dependent on external capital. Higher rates make investors demand a clearer path to monetization.

AI startups

Large pressure

Valuations depend heavily on discounted future cash flows and access to venture capital. Higher rates particularly hurt companies whose revenues are distant or speculative.

Data-center developers

Moderate-to-large pressure

These are extraordinarily capital-intensive, long-duration projects. Financing costs directly affect project economics.

GPU/accelerator suppliers

Initially modest; eventually meaningful

Existing compute shortages and contractual commitments can insulate near-term demand. But slower infrastructure deployment eventually feeds back into equipment orders.

Power/electrical infrastructure

Moderate pressure

Projects with long lead times and large upfront investment become harder to finance, although genuine power scarcity can preserve demand for some projects.

Cloud AI services

Mixed

Higher rates can restrain customers' IT budgets, but AI can also be justified as a way to reduce labor costs or increase productivity.

Enterprise AI software

Mixed/slightly negative initially

Discretionary experiments are vulnerable, while applications with measurable ROI may actually become more attractive if companies are under pressure to improve productivity.

AI applications with little capex

Relatively resilient

Higher rates don't materially change their marginal cost of development or deployment.

AI infrastructure with long-term contracts

More resilient

Contracted cash flows can support project financing even when the general cost of capital rises.

Existing profitable technology companies

Relatively resilient

High cash generation makes them less dependent on external financing.


Also, it matters greatly “why” interest rates are climbing. If rates rise because the economy is strong and inflation remains persistent, that is a very different scenario from rates rising because of a recession. And, at the moment, U.S. gross domestic product is still growing, according to the Federal Reserve.


Higher rates “should” put pressure on some suppliers in the AI value chain, such as high-performance-compute-as-a-service suppliers. But some will argue that better capital investment discipline will result. 


Higher rates might even help suppliers of used graphics processor units, as such units might retain their value better.


Effect of higher rates

Likely impact on AI

Higher cost of debt

Negative for leveraged AI infrastructure

Higher required return on new projects

Negative for marginal data centers and GPU deployments

Lower equity valuations

Negative, particularly for startups dependent on new funding

More expensive private credit

Negative for neoclouds and infrastructure developers

Pressure on hyperscaler free cash flow

Negative, potentially causing capex discipline

Higher discount rate applied to future AI profits

Negative for valuations

Stronger incentive to monetize existing GPUs

Mixed/positive—could increase utilization

Higher hurdle rate for speculative projects

Potentially positive for industry discipline

Cash-rich hyperscalers' ability to self-finance

Mitigates the effect


As usual, higher borrowing costs will be a negative for startups and smaller firms more reliant on borrowed money. 


AI layer

Rate sensitivity

Nvidia/AMD-type highly profitable chip suppliers

Low–moderate

Hyperscalers

Moderate

Large profitable AI software companies

Moderate

AI infrastructure developers

High

Neoclouds

Very high

Frontier-model startups

High

Early-stage AI startups

Very high


Still, ceteris paribus (“all other things being equal”) rarely describes events in the real world. All other things will not remain equal. Higher interest rates “should” slow AI investment. But competitive pressures within the industry, evidence of value and financial impact, capital availability and all sorts of other potential macroeconomic influences are likely to have an effect as well.


So interest rate increases might not have the slowing impact one might otherwise expect. Nor might the impact of a high CAPE necessarily cause the bursting of the "AI bubble." There are simply too many moving parts.


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Maybe Higher Interest Rates or High CAPE Ratios Will Not Derail AI Investment

The issue economists and financial analysts always face when attempting to assess the impact of higher interest rates on equity valuations i...