Goldman's Top Strategist Says AI Capex Is Creating an Earnings Bubble, Not a Valuation One

Fortune (17 September 2026) reported a Goldman Sachs client research note titled "Competition for Capital" from chief global equity strategist Peter Oppenheimer. The note hardens his early-August thesis that technology stocks may face an earnings bubble rather than a valuation bubble.

This is a Goldman client strategy note. It is not a Federal Reserve speech, not a rating downgrade, and not a call that a bubble "definitely" exists. Oppenheimer still hedges that last point.

The mechanism is now the title. AI infrastructure capex and government borrowing, he argues, are competing for the same savings pool, which lifts the global cost of capital. Capital spending among AA-rated technology issuers grew 65 percent year over year in the second quarter, the tenth straight quarter that aggregate AA capex growth has topped 35 percent.

He still lists reasons today looks unlike 2008 banks: profits remain robust, coverage ratios are high, and AI compute demand is still outstripping supply. He also warns that any slowdown in profit growth, with a higher cost of capital, could pressure equity prices from the hyperscalers through the chip and infrastructure suppliers.

Related capital-demand tape includes Generac locking $2.4 billion of Amazon generators, the Treasury 10-year yield hitting 5 percent, and SoftBank's $11.9 billion loan for OpenAI funding.

If you mark AI infrastructure names, treat this as a cost-of-capital and earnings-quality warning, not a valuation-multiple crash call, and stress-test 2027 cash flows against a higher long-end yield rather than a lower P/E.