Nasdaq 100: Not a Technology Index
The Nasdaq 100 holds the hundred largest non-financial companies listed on the Nasdaq exchange, weighted by market value. It is neither the Nasdaq Composite, which holds thousands, nor a technology index by definition - though its weighting makes it behave like one.
How it works
The rule is exchange, size and one exclusion. The hundred largest companies listed on the Nasdaq exchange, excluding financial companies, weighted by market value.
It is not the Nasdaq Composite. That index holds every company on the exchange — thousands of them, including a long tail of very small ones — and the two are quoted interchangeably in headlines despite behaving differently.
Nothing in the rule mentions technology. It contains retailers, drink manufacturers, biotechnology firms and transport companies, because the criterion is where a company listed rather than what it does.
What the weighting does
Size weighting produces the technology character. The largest Nasdaq-listed companies happen to be technology companies, so weighting by market value concentrates the index there regardless of the rule.
A small number of companies account for most of the movement. Holding a hundred names is not holding a hundred equal positions, and the daily move is largely a weighted average of the largest few.
A capping rule exists precisely because of that. When the largest holdings exceed defined thresholds the index is rebalanced to reduce them, which is an admission that pure size weighting produces a concentration the index provider is uncomfortable with.
It is more volatile than a broad market index. Fewer companies, one exchange, no financials and a concentrated top end all push in the same direction. That extra movement is not extra return — it is extra variability, and it needs a correspondingly smaller position.
In practice
Trackers for it are cheap and widely available. The competition among providers has pushed fees on major index products into single-digit basis points, which is a genuine improvement for holders.
Its futures carry enormous volume. That means tight spreads and deep liquidity for traders, and it is why the index appears constantly in day-trading material.
Over a decade the concentration explains most of the record. A period in which the largest technology companies did exceptionally well is a period in which this index did exceptionally well, and the two facts are the same fact.
Earnings season is concentrated risk. A gap in the whole index can come from one company’s results, which is single-stock risk arriving through an index position.
A stop in the futures offers no gap protection. The contract trades nearly around the clock, and the largest moves still arrive as jumps rather than as a slide through your level.
Trading costs apply as they do anywhere. The spread and any commission come off every round trip, whether the position is a tracker fund or a futures contract.
One structural feature separates it from every broad index and it is easy to miss: the exclusion of financial companies. Banks, insurers and asset managers are absent by rule, which removes an entire sector that behaves differently from the rest of the market — it tends to do well when interest rates rise, which is often when technology does badly.
So the index has no internal counterweight to its largest exposure. A broad market index holds banks alongside technology and the two partially offset; this one holds the technology and not the offset. That is the substantive reason it moves further in both directions, and it is a construction decision rather than a market condition.
What the Nasdaq 100 is not
It is not the Nasdaq Composite. Different index, different construction.
It is not a technology index by rule. It is one by weighting.
It is not diversified by holding count. A few names dominate.
And it is not a US market index. One exchange, no financials.
How this connects
Its largest holdings are mostly growth stock names, which is why the index is so sensitive to anything that changes how far ahead the market is willing to value profits.
Concentration risk is the practical consequence of the weighting. A single earnings report from one of the top holdings can move the whole index, and the capping rule only limits that rather than removing it.
Beta against a broad index is usually above one. The correlation coefficient between the two is high, so it tends to fall further in a market correction or a bear market rather than offering shelter.
Several instruments track it. An ETF tracking the index competes on expense ratio and tracking error, while mini futures and micro futures give traders the same exposure in contract form.
It is also the base for many geared products. A leveraged ETF or an inverse ETF on the index resets daily, so the index’s higher volatility makes their decay worse than on a calmer benchmark.
Holding it beside an S&P 500 ETF is less diversification than it looks. The biggest positions in one are among the biggest in the other.
Its futures trade almost around the clock. News arriving overnight is often priced before the cash session, and the premarket carries that repricing into the open.
And rebalancing is how an investor controls the drift. A holding that has grown far beyond its intended weight can be trimmed back to plan.
When it fails as a proxy
Using it as “the market” produces a distorted reading. No financial companies, one exchange and a concentrated top end make it a specific slice, and days when it diverges sharply from a broad index are days when the difference is the story.
A second failure is treating its record as evidence about indices generally. Its history is a history of one group of companies during one favorable period.
A third is holding it alongside a broad fund without checking. The overlap is substantial and the largest positions are the same ones.
A fourth is sizing it like a broad index. More volatility for the same money is more risk.
And a fifth is ignoring what the capping rule implies. An index that has to be rebalanced to limit its largest holdings is telling you something about its own construction.
The original data
Of the 24,971 trading and investing videos in this site’s corpus, 48 have “nasdaq” in the title at a median of 7,612 views across 41 channels. “S&P 500” returns 51 at a median of 9,658 across 43 channels, “dow jones” returns 5 at a median of 6,250, and “index fund” returns 132 at a median of 69,951. Repeat appearances of the same video count once.
The question: Five stocks are 40% of it. Still diversified?
48 videos at a median of 7,612 views against 132 index-fund videos at 69,951 is the pattern worth noting. The material about trading this index reaches a ninth of the audience per video — the demand is for the boring long-term holding and the supply is concentrated on the exciting short-term instrument. Before buying it, look up the current top-ten weight, because that single figure tells you more about what you are holding than the name does.
Related
Index funds explains weighting and what a holding count really means. Nasdaq trading covers trading the index and its futures. And Dow Jones is the other headline index and its very different construction.
The thing worth knowing before trading it is that you are trading a small number of companies with a hundred names attached. When five of them report in the same fortnight, that fortnight is the index, and the other ninety-five are decoration.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.