Nasdaq-100

What it means

The Nasdaq-100 tracks large non-financial companies listed on the Nasdaq Stock Market. It is an index, not a stock, an exchange or a portfolio that investors can trade directly. Eligibility and constituent weights follow index rules; the membership and weights can change over time.

The name refers to 100 companies, although the number of securities can differ when a company has more than one eligible share class. It is not a list of the 100 largest US companies across all exchanges, and it excludes financial companies under its eligibility rules.

The index is often used as a benchmark for funds and portfolios. Its modified market-capitalization weighting gives larger companies more influence than smaller ones, subject to index rules that can adjust weights. As a result, an equal-sized percentage move in two constituents need not have an equal effect on the index.

How it is calculated

An index provider maintains constituent shares, prices, weights and an index divisor. A simplified point-in-time calculation is Index level = (Σ adjusted constituent market values) / index divisor, where:

• Σ means add across all securities in the index.
• Adjusted constituent market value is a security’s price multiplied by the share count used for index calculation, after applicable weighting adjustments; it is measured in US$ when prices are in US$.
• Index divisor is a scaling factor, expressed in US$ per index point in this simplified presentation. It helps maintain index continuity when specified changes, such as constituent or share-count changes, occur.
• Index level is measured in points, not US$.

This describes the mechanics, not the complete Nasdaq-100 methodology. In particular, modified weighting rules can constrain individual or combined weights; simply ranking companies by market value and dividing by 100 will not reproduce the published level.

Worked example

Assume a hypothetical, simplified index with two securities and no weighting adjustments. It is not an example of actual Nasdaq-100 constituents or published index values.

1. Company A has 100 million index shares at US$50 each: its index market value is US$5 billion.
2. Company B has 100 million index shares at US$50 each: its index market value is also US$5 billion.
3. The combined value is US$10 billion. With a hypothetical divisor of US$10 million per point, the index starts at 1,000 points.
4. A rises to US$60 while B stays at US$50. Their combined value becomes US$11 billion. With the divisor unchanged, the index becomes 1,100 points—a 10% increase, even though A’s price rose 20%.

A real index has many more securities, and its weighting adjustments and divisor must be accounted for. This example excludes dividends and trading costs.

Why it matters before you trade

An index move summarizes its constituents; it does not describe the execution conditions for any particular stock. Two Nasdaq-100 constituents can have different bid-ask spreads, daily volumes and volatility. The size of an intended order relative to a stock’s typical volume can also affect estimated market impact.

If a basket is intended to resemble the index, comparing its weights with the index’s weights can reveal concentration or sector differences. A basket of a few constituents is not automatically diversified simply because those companies belong to the Nasdaq-100. Nor does an index level state what a fund tracking the index will return after its own costs and tracking differences.

How PreTrAIde uses it

The product facts do not say that PreTrAIde uses Nasdaq-100 membership or the index level as an input or benchmark. A related pre-trade analysis checks the stocks actually entered in a basket: each line has a side, quantity and execution conditions.

PreTrAIde estimates measures including spread, participation in daily volume, market impact and daily volatility. It also reports basket breakdowns and concentration, then provides decision-support verdicts and reasoning for the basket and its lines. Those assessments concern the submitted stocks and conditions, not an index forecast or a recommendation.

Common mistakes

• Confusing the index with Nasdaq: Nasdaq is a stock exchange; the Nasdaq-100 is an index of selected Nasdaq-listed securities.
• Assuming equal weights: Larger constituents generally have greater influence, although modified weighting rules can adjust their weights.
• Treating index movement as a fill price: An index has no bid or ask at which a stock order executes.
• Assuming membership guarantees liquidity: A constituent’s spread and volume still matter for a specific order.
• Ignoring the return measure: A price index and a dividend-inclusive total-return measure answer different questions.