QuantStreet October 2026 Letter: Interest Rate Worries

interest-rate-worries

Societal angst about AI continues to grow. Whether it’s concern about misalignment or potentially misdirected investment, the AI-may-be-bad narrative is gaining traction. In stark contrast, the AI trade in financial markets was alive and well in September of 2026. Leading the way were Bitcoin and the iShares USA Momentum ETF (top holdings: AMD, Micron, Intel, Cisco, Applied Materials, etc.), with Nasdaq also positive. Surprisingly, commodities and the dollar both rallied, despite dollar strength usually being negative for commodities and news that oil shipments through the Strait of Hormuz have rebounded to 80% of their pre-war levels. The rest of the US stock universe fared poorly. Mid-caps and small-caps had an awful month (as did the equal-weighted S&P 500), and rate-sensitive sectors and assets got hammered (REITs, utilities, financials, and gold).

performance 9-30-26

But the real carnage was reserved for fixed income markets. Ten-year Treasury yields finished the month over 50 basis points (0.5%) higher than their August close. And parts of the US fixed income markets were down between 2.3% and 5%.


VGIT

Theories for why range from a loss of confidence in the dollar (hard to argue given the dollar’s appreciation in September), to a loss of confidence in the US government’s ability to repay its debts (also hard to argue given stable inflation breakevens, since the path to default for the US is through inflation), to anticipated high economic growth with large demand for capital by the hyperscalers. What gives more credence to this last point is that, usually, with such a large increase in interest rates, stock prices—which represent the discounted present value of future dividends—would be meaningfully lower. The fact that this did not happen suggests that markets believe that the numerator effect, i.e., higher future earnings and thus higher future dividends, is enough to offset the increase in the denominator, i.e., discount rates.

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