When a headline says “the market is falling,” I want to ask a second question: which market? The largest stocks can dominate the daily conversation, but their performance is not a vote from every listed company. October offers a useful example. Technology-heavy shares weakened sharply, while some other equity benchmarks finished the month higher. That is not the same thing as saying everything outside technology was safe.
01 / THE OCTOBER SPLITOne month. Four different experiences.
From September 30 through October 30, the Nasdaq Composite fell 5.30%, while the S&P 500 declined 0.93%. The Dow gained 1.70% and the Russell 2000 rose 0.54%. These comparisons use the same start and end dates and the same price-return convention. The S&P provider’s published October return also rounds to −0.93%. [1] [2]
Source: Yahoo Finance daily histories; author calculations. Nasdaq means the Composite, not the Nasdaq-100. Different constituents and weighting methods mean these are comparisons, not an attribution of the market’s decline. [1]
The final session was less reassuring: all four indices fell on October 30, including the Dow and Russell 2000. The S&P 500 lost 1.82% that day. [1] [2] So the answer changes with the time horizon. October showed meaningful divergence; Friday showed selling across several benchmarks. A positive monthly result does not mean a stock or index escaped the latest sell-off.
02 / WHY HEADLINES CAN MISLEADThe biggest companies have the loudest voice
The conventional S&P 500 weights companies by float-adjusted market capitalization. A large constituent therefore matters much more than a small one. Its equal-weight counterpart uses the same companies but resets each company to approximately 0.2% at quarterly rebalances; those weights drift between rebalances. The Dow, meanwhile, is a price-weighted index of only 30 blue-chip companies. It is not a direct measure of the average U.S. stock. [3] [4]
Size-weighted
A 10% fall in the 60%-weight stock subtracts about 6 percentage points if the others are unchanged.
Equal-weighted
The same fall subtracts about 2.5 percentage points when that stock starts at a 25% weight.
Numbers inside bars are hypothetical portfolio weights in percent. Simplified one-period arithmetic excludes costs and rebalancing.
This is why I would compare equal-weight and cap-weight performance before assuming every business faces the same problem. However, equal-weight outperformance alone is not proof that most stocks rose: it can simply mean they fell less. It also changes sector exposures and the influence of smaller companies within the index. I have not included an October equal-weight return here because I did not verify a like-for-like index series for this snapshot.
03 / WHAT MAY BE CHANGINGFrom rewarding the story to testing the cash flow
Reuters’ October 30 reporting described renewed investor scrutiny of AI investment, rising spending commitments and the speed at which those investments might generate returns. [5] That is a plausible backdrop to technology weakness, but it does not isolate what caused each stock’s move. Results, guidance, positioning and broader discount rates can all matter at once.
My interpretation is that the question is shifting from “who has AI exposure?” toward “whose investment can earn a return?” Higher spending can increase future capacity while reducing cash available today. The market can remain positive about AI adoption and still demand a lower purchase price for a particular business. This note is not a second financing deep dive; it asks whether the repricing is concentrated or spreading.
The Fed is part of that backdrop, not the whole explanation. Holding its policy rate steady does not lock Treasury yields or corporate funding costs in place. If the required return on equities rises, investors may pay less for the same future earnings. But I would not attribute October’s index divergence solely to the Fed or claim that every technology company has the same rate sensitivity.
04 / ROTATION OR BROADER STRESS?Three things I would check next
Are more stocks holding up?
Compare advancing and declining shares, equal-weight performance, and the proportion of constituents above a 200-day moving average. Improvement across several measures is more convincing than one resilient index.
Do profits support the new leaders?
Watch forward guidance, margins and cash generation outside the largest growth names. Defensive shares falling less is different from economically sensitive businesses showing improving demand.
Is equity weakness reaching financing?
Look for persistent widening in corporate credit spreads alongside weaker shares. That would raise concern about broader risk appetite. High-yield ETF prices alone are not a clean spread measure because Treasury yields also affect them.
These are tests for a view, not signals I am claiming have all turned positive today. A proper breadth study also needs point-in-time constituents, consistent observation dates and a clearly defined stock universe. Comparing four benchmarks is a starting point, not a count of how many individual companies are rising.
05 / MY EQUITY VIEWBe selective without pretending concentration does not matter
I do not think the choice has to be “buy Big Tech” or “avoid equities.” I would rather ask what expectations I am paying for, how resilient the cash flows are, and whether my portfolio holds several versions of the same risk. Owning a broad index alongside multiple large technology stocks can produce more overlap than the number of holdings suggests.
Over the next few months, I would become more constructive if broader earnings held up while participation improved and financing conditions remained orderly. I would become more cautious if selling spread across sectors, guidance weakened and credit risk repriced together. That would challenge the idea that this is mainly a leadership adjustment.
Sources & research notes
Original synthesis for Kevin Lu Research, published October 31, 2026. Market observations are historical; forward-looking discussion is conditional analysis, not a calibrated forecast or personalized investment recommendation. No numerical advance/decline or moving-average breadth claim is made without a verified constituent dataset.
- Yahoo Finance · S&P 500 historical closesAlso: Nasdaq Composite, Dow, Russell 2000. Retrieved October 31, 2026. Monthly price return = October 30 close divided by September 30 close, less one. Daily return uses October 29 and 30. Rounded only after calculation; dividends excluded. The four underlying comparison observations are preserved in this dated snapshot.
- S&P Dow Jones Indices · S&P 500October 30 published price return: −1.82% daily and −0.93% month-to-date. Cross-check for the S&P figures.
- S&P Dow Jones Indices · S&P 500 Equal Weight IndexSame constituents as the capitalization-weighted index; approximately 0.2% per company at quarterly rebalance. The four-stock graphic is an original hypothetical illustration, not S&P constituent data.
- S&P Dow Jones Indices · Dow Jones Industrial AveragePrice-weighted construction and 30-company universe. Index differences limit any conclusion drawn from the Dow/Nasdaq comparison.
- Reuters · October 30, 2026: Nasdaq faces $2 trillion wipeout as AI spending fears deepenContext for AI spending and return concerns. Its contemporaneous Nasdaq-100 estimate is not used as the final Nasdaq Composite return in this article.