Renewed US-Iran tensions send crude and bond yields surging, dragging major indexes lower even as Nvidia's record buyback lifts its own shares against the tide.
US stocks fell sharply on Monday, September 28, 2026, in New York after President Donald Trump rejected an Iranian peace proposal aimed at ending the conflict between Washington and Tehran and reopening the Strait of Hormuz, according to Reuters. The Dow Jones Industrial Average dropped 347.11 points, or 0.67%, to 51,481.51; the S&P 500 declined 59.72 points, or 0.77%, to 7,683.69; and the Nasdaq Composite lost 248.34 points, or 0.92%, to 26,820.38. The selloff came despite a 1.6% gain in Nvidia shares after the chipmaker's board approved an additional $150 billion in share buybacks.
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Oil Spike Reignites Inflation Anxiety on Wall Street
The immediate trigger for Monday's decline was a jump in crude prices after Trump rejected Iran's proposal, which reportedly involved reopening the Strait of Hormuz and resuming nuclear talks within seven days if Washington accepted its conditions, according to a market summary cited by Reuters. Brent crude futures rose $2.28, or 2.2%, to $106.60 a barrel at 10:27 a.m. Eastern time, while US West Texas Intermediate crude gained $1.70, or 1.8%, to $94.11, Reuters reported. Prices later pared some gains as investors weighed the possibility that Qatari mediators might broker talks between the two countries.
The Strait of Hormuz remains one of the world's most critical energy transit corridors, and any prolonged disruption threatens to tighten global crude and refined-product supply while raising freight and insurance costs. However, the available reporting confirmed market concern and price movement rather than a verified closure of the strait or a quantified supply loss. Monday's equity selloff reflected investors pricing in risk and uncertainty, not confirmation that a full-scale energy disruption had already materialized.
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Treasury Yields Climb Toward Multi-Year Highs
Compounding the pressure on equities, the US 10-year Treasury yield hovered around 5.20%, near its highest level since the mid-2000s, according to a market assessment cited in the research. Higher yields reduce the relative attractiveness of stocks, particularly technology and growth names whose valuations rest heavily on projected future earnings. As borrowing costs rise, the present value of those distant profits diminishes, prompting investors to rotate away from richly valued growth stocks.
The rise in yields was tied directly to fears that elevated oil and diesel prices could push inflation back above the Federal Reserve's comfort zone. Reuters reported that Federal Reserve officials had signaled further rate increases could be necessary if price pressures failed to ease, a warning that followed a 25-basis-point rate hike earlier in September. The available reporting did not name every official involved or confirm any new formal policy decision, meaning the remarks should be understood as guidance about a possible future path rather than an announced rate change.
Nvidia's Record $150 Billion Buyback Bucks the Trend
Nvidia's board authorized an additional $150 billion under its existing share-repurchase program, lifting its total remaining authorization to $235 billion, the company confirmed. The move was described by Reuters as the largest single share-buyback authorization in corporate history, surpassing Apple's $110 billion approval in 2024. The announcement came as Nvidia's stock traded near its lowest earnings multiple in more than a decade, according to Reuters, suggesting management viewed shares as undervalued despite the company's central role in the artificial-intelligence boom.
The buyback functions as both a financial signal and a strategic statement. It demonstrates Nvidia's confidence in its long-term cash-generation capacity even as intensifying AI-chip competition and investor scrutiny over the durability of AI-related spending weigh on sentiment across the sector. The authorization does not obligate Nvidia to repurchase the full amount immediately, nor does it set a fixed timetable; it simply grants the company flexibility to buy shares as market conditions allow. Nvidia's 1.6% gain stood out starkly against a broader market retreat, helping to cushion losses in the technology sector.
Tesla Slides on Delivery Concerns as Corporate Signals Diverge
While Nvidia rallied, Tesla moved in the opposite direction after J.P. Morgan lowered its price target on the automaker, citing weak third-quarter deliveries, according to Reuters. The available reporting did not specify the revised target figure or the exact delivery shortfall, so those details remain unconfirmed pending further disclosure. The downgrade highlighted a company-specific pressure distinct from the macroeconomic forces weighing on the broader market, raising questions about demand, pricing strategy and production execution heading into the final quarter of the year.
The contrast between Nvidia's buyback-driven rally and Tesla's price-target cut illustrates how individual corporate developments can diverge sharply from broader index movements even within the same trading session. Investors nonetheless remained focused primarily on the macro backdrop, where geopolitical risk, energy costs, inflation expectations and interest-rate policy intersected to drive the day's overall direction.
What Comes Next for Markets, the Fed and the Iran Standoff
Analysts and investors are now watching whether Qatari-mediated talks between Washington and Tehran can advance, a development that could ease oil prices and Treasury yields if diplomacy succeeds. Conversely, a breakdown in negotiations or further disruption tied to the Strait of Hormuz could deepen inflation concerns and increase pressure on the Federal Reserve to act. Reuters noted investors will continue monitoring Fed commentary alongside incoming inflation, labor-market and energy data for signals on whether additional rate increases are likely.
Monday's trading session did not confirm that the Federal Reserve will raise rates again, nor did it establish that the Strait of Hormuz faces a prolonged closure. It demonstrated instead that markets are actively repricing those risks in real time, with oil and Treasury yields serving as the primary transmission channels between geopolitical uncertainty and equity valuations across Wall Street.
