U.S. equity markets return Tuesday from the Memorial Day break with the Dow Jones Industrial Average and the S&P 500 Equal Weight index both sitting at all-time highs, extending a rally that has persistently defied the macro headwinds that, on paper, should have broken it months ago. The short version: artificial intelligence earnings growth has been large enough and consistent enough to render geopolitical risk secondary. Investors have not ignored Iran. They have simply done the arithmetic and concluded that it does not matter more than the numbers do.
That calculus has been validated repeatedly in 2026. The Iran conflict disrupted Hormuz shipping, elevated Brent crude to the low $100s, and introduced a durable inflation variable that complicated the Federal Reserve’s rate path. None of it broke the tape. The S&P 500 absorbed each escalation and continued higher, not because investors are complacent about supply risk, but because the earnings growth offsetting that risk has been extraordinary. As of mid-May, 84% of S&P 500 companies reporting beat first-quarter estimates. Operating margins hit an all-time high of approximately 16%. Revenues are growing at 10% year-over-year, with profits outpacing that figure by a meaningful spread. When the fundamental backdrop is this strong, geopolitical friction becomes a discount rate argument rather than an earnings argument, and the market has consistently chosen to emphasize the latter.
The AI theme is doing the heavy lifting. Technology sector earnings have not merely beaten estimates; they have reset them. The Magnificent 7 cohort has posted results that, relative to their price-to-earnings multiples, look reasonable rather than stretched — an unusual condition in a late-stage bull market, and one that removes the valuation compression argument that bears have leaned on for over a year. When growth is fast enough, even elevated multiples get earned into quickly. That is the structural condition that has held since late 2025, and nothing reported in the most recent quarter has materially altered it.
The Iran/Hormuz situation contributes to the backdrop in one concrete way: oil. WTI settled Friday near $98 and Brent near $105, levels that represent a persistent tax on corporate margins in energy-intensive sectors and a floor under headline inflation. Barclays has flagged a supply deficit of 6 to 8 million barrels per day, with U.S. inventories near their lowest since 2020. Even in a full Hormuz reopening scenario, that deficit does not resolve immediately. This matters for the Fed more than it matters for the equity market directly, but the two connect through the rate path: sustained $100 oil makes early rate cuts harder to justify, which keeps long-duration pressure on bonds and limits multiple expansion in rate-sensitive parts of the equity market. That is a headwind, not a ceiling, and the market has been trading accordingly — rotating toward quality growth and away from rate-sensitive cyclicals rather than de-risking wholesale.
Tuesday carries its own variables. Kevin Warsh was sworn in as Federal Reserve chairman Friday, and any public statement he made during the White House ceremony will arrive into Tuesday’s open as the first substantive signal of his policy posture. Warsh has historically leaned hawkish on inflation. If his early remarks reinforce that posture, Treasury yields could move, and rate-sensitive sectors — utilities, real estate, long-duration tech — will respond. The earnings calendar for the day is thin at the index-moving level: AutoZone, Box, Semtech, and SQM headline the list. None will set the tone for the broad market. SQM is worth watching as a lithium proxy with exposure to EV supply chain dynamics, but it will trade on its own fundamentals rather than driving sentiment.
The one structural caution worth noting going into Tuesday is breadth. The headline indexes are at records, but market breadth has been narrowing in recent sessions — a pattern in which fewer stocks drive the index higher while the average stock underperforms. That is a late-stage distribution signal historically, though it can persist for extended periods when a concentrated group of mega-cap names is growing fast enough to justify the weight. In the current market, the AI cohort provides that justification. The question is duration: how long concentrated earnings growth in a small number of names can substitute for broad participation. That answer is not available Tuesday, but it is the right frame for the second half of 2026.
For Tuesday specifically, the structural setup is constructive. The three-day break historically reduces early volume, and the Friday close at all-time highs leaves buyers in control of the narrative. The Iran variable is present but priced. The new Fed chair is the swing factor — known unknown, directionally hawkish, but without a stated position on current conditions. Absent a significant Hormuz escalation over the weekend or a Warsh statement that resets rate expectations sharply, the path of least resistance Tuesday morning is the same one it has been for most of 2026: long AI, long earnings momentum, short the thesis that geopolitical risk will finally be the thing that ends it.
It has not ended it yet. The market has made clear it intends to require a much larger disruption before reconsidering that position.
Bottom Line: A Split Market, Not a Unified One
The honest verdict for the near term is not boom, not bust, and not clean stagnation. It is a structural split that makes the headline indexes misleading as a read on market health.
Mega-cap AI and technology names are in a localized boom. Earnings growth is fast enough to justify current multiples, institutional positioning remains heavy in the cohort, and there is no obvious catalyst to rotate out of names that keep beating numbers. Nvidia, Microsoft, and the broader AI infrastructure complex are not in a bubble in the classical sense — a bubble requires valuation detachment from fundamentals, and the fundamentals in this group have repeatedly caught up to the price. That dynamic does not end at a fixed date; it ends when earnings growth decelerates materially, and there is no evidence of that yet.
The S&P 500 index, as a market-cap-weighted construct dominated by that same cohort, will continue to reflect the AI boom more than the underlying economy. The index can make new highs on the strength of ten names while the average stock goes nowhere. That is approximately the condition that has prevailed, and it is likely to continue. Calling the S&P 500 a boom market is accurate for the names that drive it and misleading for everything else inside it.
Small caps are the clearest bust-adjacent case. The Russell 2000 is caught between sustained oil-driven inflation, a hawkish incoming Fed chair, and earnings growth that cannot match the mega-cap tier. Rate-sensitive balance sheets, limited pricing power, and no AI tailwind of comparable magnitude put small caps in a structural underperformance posture for the foreseeable period. There is no near-term catalyst to change that equation. A Hormuz resolution and a resulting oil price collapse would be the most direct trigger, but that outcome is not priced as likely and has been flagged as false before.
Broad market stagnation — ex-AI — is the base case. The economic backdrop is not deteriorating sharply enough to produce a broad bear market, but the combination of $100 oil, a Fed that has limited room to cut, and narrowing breadth removes the conditions for a broad-based rally. What that produces is an index chart that looks strong because it is cap-weighted toward a handful of compounding machines, sitting on top of a market that is flatter and more fragile than the headline number implies.
The practical read: overweight large-cap AI and technology, neutral to underweight the S&P 500 equal weight, avoid small caps until the rate picture clarifies. The boom is real, but it is narrow. Treat the index as a proxy for ten companies, not five hundred.
