Nicolai Tangen Warns AI Stock Valuations Could Turn Record Gains Into Heavy Losses

A record gain is not proof that markets are safe. Nicolai Tangen, chief executive of Norway’s Government Pension Fund Global, said investors should be more cautious after a powerful rally driven partly by technology and artificial-intelligence valuations.

The warning arrived as the fund reported a 9.4% return for the first half of 2026, equivalent to 1,753 billion Norwegian kroner, or roughly $184.6 billion. Tangen’s message was not that an AI crash was certain or imminent. It was that the gains themselves had increased awareness of how much could go wrong if valuations, earnings expectations or market conditions changed.

What Tangen warned about

Tangen identified AI valuations, inflation and geopolitical conflict among the reasons for caution after the rally. As he put it in comments reported by Bloomberg, investors become “a bit more nervous” and “more conscious about all the dangers” after such strong performance.

Earlier reporting also described an AI bubble as a major risk scenario for the fund, alongside geopolitical shocks. That scenario was reported as potentially reducing the fund’s value by 35%; it is a stress scenario, not a prediction that such a loss will occur.

The practical concern is that market prices may already assume exceptionally strong growth in AI-related businesses. If future profits, demand or returns on infrastructure investment fail to meet those expectations, expensive shares can reprice quickly. That would affect investors who benefited from the boom—and large institutional portfolios holding the companies at its center.

Why the record return does not settle the question

The fund’s first-half result demonstrates the upside of the AI-led rally. Its investments benefited from gains in global technology companies, and the fund has previously said that it earned substantial returns from the largest U.S. technology companies.

But the same exposure creates a second possibility: a reversal in major technology stocks could pull down the fund’s overall value. Record performance measures what happened during the reporting period; it does not establish that current valuations are sustainable.

That is the distinction at the heart of Tangen’s warning. AI can be economically transformative while AI-related shares are temporarily overpriced. A correction would not show that the technology has no value. It would show that market expectations had moved faster than the earnings and cash flows needed to support them.

The warning is not a call to abandon AI

Tangen’s comments should not be read as a recommendation to sell every AI-related investment. The fund continues to benefit when technology leaders and semiconductor companies rise, and its mandate is to invest Norway’s petroleum revenues across global markets rather than make a simple all-or-nothing bet on one theme.

His point was about vulnerability. When optimism, market concentration and high valuations reinforce one another, a shift in expectations can affect many holdings at the same time. Geopolitical conflict and inflation could add further pressure, which is why Tangen discussed AI valuations alongside broader macroeconomic and political risks.

What investors should take from the warning

The most useful takeaway is not a precise crash forecast. It is a framework for separating three questions:

• Is the technology valuable? AI may produce lasting economic benefits.
• Are current prices justified? That depends on future earnings, competition, spending and returns on investment.
• How exposed is a portfolio if expectations change? Broad diversification can reduce some risks, but it cannot eliminate losses during a market-wide technology sell-off.

Norway’s oil fund offers a clear example of this tension: the AI rally helped produce an extraordinary first-half result, while the fund’s chief executive simultaneously warned that the market’s future risks had become harder to ignore.

The message is therefore cautious rather than predictive: exceptional returns can coexist with substantial downside risk, and a strong recent performance may be the reason to examine valuations more closely—not a reason to assume the rally will continue.