S&P 500 Falls As Investors Get Spooked By High Costs Of AI

The S&P 500 fell as surging AI costs and weak earnings from Alphabet and Intel rattled markets.

Compared to the previous week, the S&P 500 (Index: SPX) didn't change much in the trading week ending on Friday, 30 October 2026. The index closed out the week at 7,580.07, down a little under 0.6% from where it closed the preceding week.

But that doesn't quite capture what happened. Stock prices rose the first three days of the week. And then, after the bell on Wednesday, 28 September 2026, tech giant Alphabet (Nasdaq: GOOG and GOOGL) reported not just that they were burning through cash to build up their Artificial Intelligence (AI) infrastructure, their advertising revenue from Internet searches was lower than expected, as their AI-based search feature underperformed expectations.

That was enough to deflate the company's stock by 12% on Thursday, 29 October 2026, which in turn, contributed to pulling the S&P 500 down by 0.3% for the day. But then after the market closed on Thursday, Amazon (Nasdaq: AMZN) and Intel (Nasdaq: INTC) delivered bad news of higher costs and falling revenues.

Of the two, Intel had the worst of it, with its stock plunging by over 28% by the time markets closed on Friday. More significantly, their combined bad news prompted investors to tank the stock prices of other chipmakers. Including the biggest company in the S&P 500, Nvidia (Nasdaq: NVDA), which lost over 4% of its value and became the second-biggest company in the index as a result by the end of the day.

By the end of the day, the S&P 500 lost over 1.8% of its total value. The latest update of the alternative futures chart shows the index' trajectory dropped to be near the bottom of the typical range the dividend futures-based model would place it assuming investors are focused on the current quarter of 2026-Q4 in setting stock prices.

Alternative Futures - S&P 500 - 2026Q4 - Standard Model (m=-2.0 from 28 Apr 2025) - Snapshot on 30 Oct 2026

With bulls spooked by the sudden rapid deflation of some of the biggest companies in the AI tech sector after their earnings outlook shifted to be worst than expected, we can expect more outsize reactions as other companies report their earnings in the next few weeks. How stock prices will react will depend greatly on what new information investors will need to absorb from the newstreams. Much like they had to do with the market moving headlines from the final trading week of October 2026....

Monday, 26 October 2026

Tuesday, 27 October 2026

Wednesday, 28 October 2026

Thursday, 29 October 2026

Friday, 30 October 2026

The CME Group's FedWatch Tool projections were unchanged. It still anticipates the Fed will next act to hike the Federal Funds Rate by a quarter point on 9 December (2026-Q4). Looking further forward in time, the FedWatch tool projects the Fed will hike this interest rate by a quarter percent on 17 March (2027-Q1). After that, the FedWatch Tool anticipates one more rate hike in 2027, coming when the Fed meets on 15 September (2027-Q3).

The Bureau of Economic Analysis reported its initial estimate for annualized real GDP growth during 2026-Q3 is +3.4%, just a bit lower than the +3.5% growth projected by the Atlanta Fed's GDPNow tool a week before.

The GDPNow tool has shifted forward to projecting the current quarter of 2026-Q4's inflation-adjusted economic growth rate, with its first estimate for the quarter coming in at 3.2%.

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