US Market Breakdown: Oil Tops $100, Chips Slide, Week of 7 September 2026

American markets came back from the Labor Day long weekend to find the oil price setting the agenda. West Texas Intermediate crude pushed through $100 a barrel on Thursday and Brent crossed $105, capping a gain of close to 9% over the week, after renewed fighting involving Iran and the shutdown of a Saudi pipeline used to bypass the Strait of Hormuz. Treasury yields climbed alongside it. By Friday's close the S&P 500 had lost 0.8% on the week, the Nasdaq Composite 0.7% and the Dow Jones Industrial Average 1.6% — and that was after a firm Friday rally.

Two inflation readings landed in the middle of it. August producer prices, published on Thursday, rose 5.4% year on year against the 5.3% economists had expected. Friday's consumer price index put headline inflation at 3.4% annually and 0.4% on the month. Traders responded by pricing a Federal Reserve rate rise this week at close to 90%, according to CME Group's FedWatch tracker — which would be the first US increase in borrowing costs since 2023.

Then Monday reopened a different fault line. A weekend call from senior artificial-intelligence executives to slow the pace of AI development knocked semiconductor shares hard, and the 10-year Treasury yield touched 5% for the first time in nearly three years.

Wall Street

US markets were shut on Monday 7 September for Labor Day, the American equivalent of a late-summer bank holiday, so this was a four-session week rather than five. It began badly. On Tuesday the Dow fell 628.18 points, or 1.18%, to 52,786.07, its worst day of the stretch, as Canadian retaliatory tariffs on roughly $20bn of American goods took effect and crude rose for a sixth consecutive session. The S&P 500 slipped 0.58% to 7,673.52 and the Nasdaq Composite 0.32% to 26,421.41.

Wednesday brought more of the same, with the S&P 500 down 0.48%, the Dow 0.77% and the Nasdaq 0.64% as Brent pushed past $101 and long-dated Treasury yields kept rising. The Russell 2000, the small-cap index and a decent proxy for domestically focused American business, fell 1.30% — a pattern that held all week. Thursday was a fourth straight decline, the day WTI cleared $100 and the hotter-than-expected producer price data arrived.

Friday broke the run. Oil eased back, the consumer price report came in close enough to expectations to be absorbed, and the Dow added roughly 500 points, or 1%, to close at 52,573.29. The S&P 500 rose 0.9% to 7,656.98 and the Nasdaq 1% to 26,333.04, with nine of the eleven S&P sectors higher. It was not enough to rescue the week: measured from the previous Friday's closes of 7,718.60 on the S&P and 26,506.99 on the Nasdaq, all three headline indices finished lower, and the Russell 2000 shed 2.4%.

Monday 14 September, the most recent completed session, gave some of Friday's bounce straight back. The S&P 500 fell 0.48% to 7,621.54, the Nasdaq 0.56% and the Dow 0.29%, with the damage concentrated in chipmakers and AI hardware rather than spread across the market. Brent rose 3.56% to $108.34 and the 10-year yield hit 5.014% intraday before settling back near 4.99%.

The week's biggest movers

Hewlett Packard Enterprise had the most violent round trip. It led the S&P 500 on Friday, rising by double digits to close at $62.08 — a gain of more than 158% for 2026 to that point — as investors read Oracle's AI spending plans as a direct read-across to the companies that build cloud hardware. On Monday it fell close to 11% after Evercore ISI's Amit Daryanani cut his rating from Outperform to In Line, arguing the shares had simply run too far.

Oracle produced the week's strangest chart. It reported first-quarter results after Thursday's close and shares jumped around 8% in extended trading. On Friday they gapped higher by more than 7% at the open, then reversed through the session to finish down about 1.7% at $150.28. The numbers themselves were not the problem, as the earnings section below sets out.

Apple rose 3.6% on Friday. On Wednesday it had unveiled the iPhone Duo, its first foldable handset, at an event billed as "Surprise and Shine" — the first keynote by John Ternus, who became chief executive on 1 September. The Duo starts at $1,999, or roughly £1,480 at the $1.35 rate prevailing that Friday, with pre-orders from 16 October and shop availability from 23 October. The shares had been down about 1.5% on the day of the launch itself before recovering.

Lumentum, which makes the lasers and optical components inside AI data centres, rose 11.14% on Tuesday after Deutsche Bank began coverage with a Buy rating and a $1,200 price target, with Evercore ISI starting at Outperform and $1,100 the same day.

Dell Technologies gained more than 10% on Friday, helped by RBC initiating coverage at Outperform and by the same AI-hardware enthusiasm that lifted Hewlett Packard Enterprise. It fell about 5% on Monday.

Nvidia, AMD, Intel, Marvell and Micron were the Monday casualties. After Anthropic chief executive Dario Amodei and other senior AI figures argued over the weekend for slowing the development of frontier AI capability, Bloomberg reported a semiconductor gauge down 5.9%. CNBC put Nvidia's midday fall at nearly 3%, Intel and AMD at about 4% each and Marvell at close to 6%. Nvidia matters more than most: it is the largest company in the world by market value and carries roughly a 7.9% weight in the S&P 500.

Company news in focus

The week's largest American deal was in regional banking. On Tuesday WaFd, the Seattle-based lender, and EverBank, the Jacksonville online bank, announced a $3.9bn reverse merger. EverBank will merge into WaFd, which survives as the listed holding company before rebranding as EverBank Financial Corp and trading on Nasdaq under EVBK. EverBank's investors will end up with about 59.2% of the combined group and WaFd's with 40.8%, creating a bank with roughly $75bn of assets. WaFd expects the deal to lift its 2027 earnings per share by around 29%, with completion targeted for early 2027.

Rumble was Monday's standout gainer after The Information reported that Anthropic is the previously unnamed customer behind a six-year, $13.7bn computing agreement, under which capacity will be leased at a data centre under construction in Maysville, Georgia. CNBC put the midday gain at 18%. The read-across was not uniformly positive for the sector: CoreWeave and Nebius both fell around 9% as investors weighed what a new entrant means for existing suppliers of AI compute.

Analyst action drove an unusual share of the week's moves. Alongside the Lumentum initiations and RBC's Dell call, Bank of America lifted its Hewlett Packard Enterprise target to $88 and Truist to $70, before Evercore ISI's Monday downgrade sent the shares the other way.

On the policy side, the US Treasury said on Wednesday it would buy back $6bn of government debt. Yields rose anyway.

Earnings in focus

A British reader used to a neat results season should note that US companies report on their own fiscal calendars, so mid-September delivers a scattered handful of off-cycle names rather than a wave.

Oracle was the big one. Its fiscal first quarter showed revenue of $19.3bn, up 30%, earnings per share of $1.92 against a $1.74 consensus, and Oracle Cloud Infrastructure revenue up 121%. Remaining performance obligations — the contracted work not yet delivered, and the metric the market now watches most closely — reached $664bn, up $209bn year on year, after more than $30bn of additional AI cloud contracts were signed in the quarter. Analysts noted approvingly that capital expenditure guidance was left unchanged. The shares still closed Friday lower.

Adobe reported record third-quarter revenue of $6.76bn, up 13%, with adjusted earnings of $6.13 per share against the $6.08 expected. It raised full-year revenue guidance to $26.576bn-$26.626bn and adjusted earnings to $24.45-$24.50 a share, and said it had passed one billion monthly active users. Shares fell 2.3% to $243.08 in after-hours trading.

Kroger, the grocery chain, reported second-quarter sales of $34.6bn against $33.9bn a year earlier and adjusted earnings of $1.09 a share, three cents ahead of consensus. Identical sales excluding fuel rose just 0.1%, and the company cut its full-year identical-sales guidance to 0.2%-0.8% from 1%-2%. The shares rose 2.7% to $58.49.

Casey's General Stores, which runs American forecourt convenience shops, was the week's worst S&P 500 performer, down roughly 16%. Diluted earnings of $7.37 a share beat the $6.68 expected and revenue of $5.68bn topped the $5.57bn forecast, but management guided fiscal 2027 EBITDA growth to 8%-10% against roughly 23% delivered in fiscal 2026. GameStop also reported, with earnings of $0.27 a share against the $0.06 expected.

Sectors in focus

Energy was the only meaningful winner, with the sector up 1.69% over the week on the back of crude's near-9% run. ExxonMobil and Chevron rose 2.3% and 2.1% respectively on the day crude spiked, with Exxon trading at $164.83 and up about 40% for the year. Energy has been the standout American sector of 2026, up 44.8% year to date against roughly 12% for the S&P 500 as a whole.

The flipside was everything that buys fuel. American Airlines fell 4.21% and United Airlines 2.91% as crude climbed, while Delta Air Lines closed Tuesday at $78.96, down about 1.5%. Rate-sensitive housing suffered too: Lennar dropped 3.5% on Friday as the average 30-year fixed US mortgage rate moved back above 7%.

Over the week as a whole, industrials fell 1.65% and financials 1.46%, the weakest of the eleven sectors. Concentration remains the structural fact of this index: the so-called Magnificent Seven accounted for 33.9% of the S&P 500 in September, which is why a bad day for a handful of chip and AI names shows up immediately in a headline index that most British investors hold through a tracker.

Macro and the Fed

The Federal Reserve has held its benchmark rate at 3.5%-3.75% throughout 2026. That looks likely to change. August's consumer price index, released on Friday, showed prices up 0.4% on the month and 3.4% on the year, with core prices up 0.3% monthly — a tenth above forecast. It followed Thursday's producer price data at 5.4% annually, and the previous Friday's non-farm payrolls, which showed 162,000 jobs added in August against a consensus of 55,000, with unemployment steady at 4.1%.

Taken together, that moved FedWatch odds of a quarter-point rise at this week's meeting from under 70% to close to 90%, with the probability of a follow-on move in October near 60%. Fed chair Kevin Warsh has said the central bank has "work to do" on prices.

Bonds moved accordingly. The 10-year Treasury yield touched 5.014% on Monday, its highest since October 2023, before easing to about 4.99%. Gold went the other way, sliding towards $4,300 an ounce and marking a third consecutive weekly fall, as higher real yields and a firmer rate outlook removed some of its appeal. Oil finished the period well above where it started, with Brent at $108.34 on Monday and WTI near $102.

Still to come

The Fed decision dominates the rest of this week.

The dot plot published alongside Wednesday's decision — the chart showing where individual policymakers expect rates to sit — will matter as much as the decision itself, given markets are already pricing a second move in October. Thursday's trio of results spans freight, housebuilding and casual dining, which between them give a reasonable read on how the American consumer and the American supply chain are absorbing $100 oil.

This article is for information and education only. It is not financial advice or a recommendation to buy, sell or hold any investment. Always do your own research.