Last Updated on 2 weeks ago by TodayWhy Editorial
Why is the stock market down today? The honest answer keeps changing shape. On Monday, July 13, it was Iran and a chip-stock meltdown. By Thursday, July 16, Iran had faded into the background and a single word from an earnings call — “capex” — was doing most of the damage.
This page tracks the story session by session. If you only read the headline number, you’ll keep being surprised by what actually moves the market from one day to the next.
Why is the stock market down today? The latest complete session
Here is where the major indexes stood at the close of the most recent finished session, Wednesday, July 15.
| Index | Move | Close |
|---|---|---|
| Nasdaq Composite | +0.62% | 26,269.23 |
| S&P 500 | +0.38% | 7,572.40 |
| Dow Jones | +0.29% (+150 pts) | 52,658.64 |
| Brent crude | +1.1%, third straight gain | ~$85.63 |
| Gold | little changed | ~$4,060/oz |
| 10-year Treasury yield | little changed | ~4.56% |
Two sessions earlier, on Monday, the market fell hard. Since then it has clawed almost all of that loss back — and then, on Thursday, chip stocks dragged it lower again for reasons that have nothing to do with the Middle East. Keep reading for the full sequence.
Engine 1: the Iran oil shock that started it
On Monday, July 13, President Trump announced the US would reinstate its naval blockade of Iran, declare itself “THE GUARDIAN OF THE HORMUZ STRAIT”, and collect 20% of the value of all cargo passing through the waterway.
Oil did what oil does. Brent crude jumped more than 9% that day, its biggest single-day gain since 2020. About a fifth of the world’s seaborne oil crosses that strait, so any threat to it lands directly in the price of crude.
Higher oil hurts stocks through three channels at once. It raises input costs for almost every company. It feeds inflation. And it pushes bond yields up, which makes stocks look relatively less attractive.
But two days later, part of that shock unwound on its own. On Tuesday, Trump dropped the 20% cargo toll plan, telling reporters that lost fee revenue would be more than offset by future Gulf investment into the US. Oil eased back from its spike before climbing again on fresh strikes — more on that below.
For the background on how the truce fell apart in the first place, see our explainer on why Trump declared the Iran ceasefire over.
Engine 2: the AI chip unwind — nothing to do with Iran
This is the part almost every “stock market down today” article buried on Monday, and it turned out to be the more durable story.
SK Hynix, the world’s leading AI memory chipmaker, had listed on the Nasdaq the previous Friday and jumped about 13%. On Monday it collapsed. Its Seoul-listed shares fell more than 15%, giving back most of the first-day gain after a $26.5 billion listing. It was the stock’s worst day on record. The damage spread instantly through the memory-chip complex. South Korea’s Kospi fell around 9%, triggering a trading halt. Micron, SanDisk, and Western Digital all fell more than 6%.
None of that was caused by a missile. It was profit-taking after an extraordinary run, colliding with growing nervousness that AI chip valuations had gotten ahead of themselves.
Update: two sessions of recovery, then the chip story returns
What happened next is the most useful part of this whole story, because it is a natural experiment. Iran did not go away after Monday — the US kept striking it. But stocks stopped reacting to Iran and started reacting to earnings instead.
Tuesday, July 14. June’s inflation report came in cooler than expected: headline CPI rose 3.5% from a year earlier, below the 3.8% forecast, as energy prices eased. Treasury yields fell, chips rebounded, and the Nasdaq led a broad recovery from Monday’s rout. The one real drag on the Dow that day wasn’t Iran — it was IBM, which tumbled toward its worst day since 1987 after missing earnings estimates.
Trump also abandoned the 20% Hormuz toll plan on Tuesday, removing one leg of Monday’s shock entirely.
Wednesday, July 15. Wholesale inflation cooled too, and all three indexes closed higher again. The US launched a fresh seven-hour wave of airstrikes on Iran and reinstated its naval blockade on Iranian ports that same day. Oil edged up on the news, but stocks barely blinked.
Instead, Wednesday’s real action was a rotation. Big Tech rallied hard — Apple hit a record high on a report it may buy an AI chip startup, while Alphabet, Amazon, and Microsoft each rose around 3%. Chip and memory stocks kept sliding anyway: Micron fell 8%, SanDisk 11%, even as equipment maker ASML raised its guidance for the second time this year. A report that a Chinese rival, ChangXin Memory Technologies, is preparing its own IPO added to the memory-stock pressure.
Thursday, July 16 (today, still developing). Taiwan Semiconductor Manufacturing reported a blowout quarter — revenue up nearly 34%, profit up 77% — and its stock still fell. The reason: TSMC raised its 2026 capital spending plan to $60–64 billion, up from $52–56 billion, and warned of higher prices. Investors read that as a sign the AI buildout is getting more expensive to sustain, not less.
The reaction spread across chipmakers. Arm Holdings, SK Hynix, and STMicroelectronics all fell sharply in early trading, and the Philadelphia Semiconductor Index was down around 15% from its recent highs. UnitedHealth, meanwhile, jumped more than 6% on an earnings beat and raised guidance, keeping the Dow roughly flat while the Nasdaq and S&P 500 slipped again.
Three sessions on, the pattern from Monday has essentially repeated itself, just with a different trigger. Iran headlines — even real ones, including actual new airstrikes — moved oil a little. Chip-sector news moved stocks a lot.
Read the shape of the selloff — it tells you which engine is stronger
Go back to Monday’s numbers. The three US indexes did not fall together. They fell in a specific order: Nasdaq down 1.55%, tech and chip heavy; S&P 500 down 0.79%, broad market; Dow down just 0.26%, old economy, heavy in energy and industrials.
The Nasdaq fell roughly six times harder than the Dow. If Monday were purely an Iran story, a war scare hitting everything at once, you would expect the pain spread far more evenly.
Instead, the Dow was cushioned by its energy stocks, which rose as oil jumped. The oil shock partly protected the Dow while the chip rout hammered the Nasdaq.
Thursday showed the same split for a different reason. UnitedHealth’s earnings beat cushioned the Dow again, while chip-heavy capex fears hit the Nasdaq hardest. The mechanism repeats even when the trigger changes: whatever is happening in the chip sector moves the Nasdaq far more than it moves the rest of the market.
Why gold fell too — the signal hiding in plain sight
Gold usually rises when investors are frightened. On Monday it fell about 1.8%. That is genuinely unusual, and it is informative.
A classic war panic sends money fleeing into gold and government bonds. That did not happen on Monday. Instead, bond yields rose and gold fell, the pattern you see in an inflation shock, not a fear shock.
By midweek, gold had roughly stabilized near $4,060 an ounce and Treasury yields had eased slightly on the cooler inflation data, consistent with the same read: traders were repricing energy costs and earnings risk, not fleeing to safety.
Is this a crash?
No — and the two sessions since Monday make that case more strongly, not less. The market gave back almost all of Monday’s loss by Wednesday’s close, which is not how genuine panics behave.
The market has now absorbed more than a dozen Iran escalations since February, including actual new airstrikes on Wednesday, and kept recovering from each one. What would make this different is not another strike. It would be either a sustained break in AI valuations — the sector carrying the entire bull market — or the Hormuz blockade actually cutting off shipping, which would turn a temporary oil scare into a permanent cost. We track that second scenario in our Strait of Hormuz oil price analysis.
Thursday’s capex-driven chip slide is the more interesting risk to watch. It’s the first sign this week that the AI trade itself, not the war, might be the market’s real fault line.
What could move the market next
- Whether the capex jitters spread. TSMC’s guidance hit the whole sector on Thursday. If Nvidia or other AI leaders confirm the same cost story in coming weeks, that is a bigger event than anything happening in the Gulf.
- Earnings season broadly. More than 87% of the roughly 40 S&P 500 companies that had reported by midweek beat estimates, including major banks. Netflix reports Thursday after the close.
- Iran escalation risk. Trump has been briefed on options to widen the conflict, including more bombing and ground forces, according to the Wall Street Journal. Iran has reportedly asked Yemen’s Houthi movement to be ready to threaten the Red Sea shipping route if the US strikes Iranian power infrastructure.
- Inflation follow-through. June’s CPI and PPI both cooled. Whether that holds once the oil-price spike from mid-July works through the data is still an open question.
The bottom line
The stock market fell hard on Monday because two unrelated things went wrong at once, and only one of them made the front page. Since then, the market has mostly shrugged off Iran — even real airstrikes — while it keeps reacting sharply to news about AI chip spending.
If you only watch the Middle East, you will keep being surprised by the Nasdaq. This week, the thing actually worth watching is what companies say about the cost of building AI infrastructure, not what happens in the Gulf.
Frequently asked questions
Why is the stock market down today?
On Thursday, July 16, chip stocks fell after Taiwan Semiconductor beat earnings estimates but sharply raised its 2026 spending plan, spooking investors about the rising cost of the AI buildout. UnitedHealth’s earnings beat kept the Dow roughly flat while the Nasdaq and S&P 500 slipped.
Is the stock market falling because of Iran?
Not this week. The US launched fresh airstrikes on Iran on Wednesday and stocks barely reacted. The bigger moves have come from earnings and AI-spending news, not the war.
Why did chip stocks fall so hard on July 13, and again on July 16?
On July 13, SK Hynix’s post-IPO rally unwound after a huge run-up, dragging memory chip stocks down with it. On July 16, the trigger was different: Taiwan Semiconductor’s earnings beat expectations, but its higher capital-spending guidance made investors nervous about AI infrastructure costs, and the selling spread across the sector.
Did the market recover from Monday’s selloff?
Mostly, yes. The Nasdaq, S&P 500, and Dow all closed higher on both Tuesday and Wednesday, helped by cooling inflation data and a rotation into Big Tech stocks like Apple and Alphabet. Chip stocks were the exception — they kept falling even as the broader market recovered.
Is this the start of a crash?
The evidence still says no. The market recovered most of Monday’s loss within two sessions, which is not typical crash behavior. The risk worth watching now is whether rising AI-infrastructure spending costs, highlighted by TSMC’s guidance on Thursday, start to weigh on tech valuations more broadly.
This article tracks market moves through the 2026 Iran war and the AI chip trade, and is updated as sessions develop. Figures reflect the most recent available data as of Thursday afternoon, July 16.