How the Nasdaq Composite picks and weights its stocks

What does the Nasdaq Composite actually hold?

Nasdaq says the index includes "all domestic and international common type stocks listed on the Nasdaq Stock Market". Eligible types include American Depositary Receipts, common stocks, limited partnership interests and ordinary shares.

Closed-end funds, exchange traded funds, preferred stocks, rights, warrants and units are not eligible. A security must be listed exclusively on Nasdaq, and it must have traded for at least one day with an official closing price.

Nasdaq states that there is no market capitalization criterion, no liquidity criterion, no float criterion, no industry or sector criterion and no geographic criterion. A company in any sector, from any country, of any size, enters the index once it lists.

As of 10 November 2026, Nasdaq's own index page showed the Composite at 25,065.87, down 187.26 points or 0.74 percent on the day.

Source: Nasdaq, Nasdaq Composite Index methodology, https://indexes.nasdaqomx.com/docs/Methodology_COMP.pdf, and the index overview page, https://indexes.nasdaqomx.com/Index/Overview/COMP, both read 11 November 2026.

How does market-cap weighting work?

A market capitalization-weighted index gives each company a weight equal to its share of the combined market value of every company in the index. The Composite's methodology says its weights derive from "the price and Total Shares Outstanding" of each security.

A three-company toy index shows the mechanism. Say the three companies are worth 600, 300 and 100 units of value. The total is 1,000. The weights are 600 ÷ 1,000 = 60 percent, 300 ÷ 1,000 = 30 percent and 100 ÷ 1,000 = 10 percent.

Nobody chooses those weights. Prices move them. If the 100-unit company doubles to 200 while the others stand still, the total becomes 1,100 and its weight becomes 200 ÷ 1,100 = 18.2 percent. The index tilts toward whatever has already grown, automatically, with no decision taken.

What the rule does to a rising stock

Cap weighting looks neutral because nobody picks a favourite, yet the rule has a consequence: it holds more of what has risen in value and less of what has fallen. That is a defensible way to hold a market, and the reason the biggest names carry the most weight.

How often the list changes

The Composite does not wait for a yearly review. Per Nasdaq's methodology, reconstitution and rebalance both run daily, effective at market open on each trading day, with no announcements. A newly eligible listing is added daily, and a security that stops being eligible is removed daily. Index shares update each day to reflect current shares outstanding.

Many indexes change their list monthly, quarterly or yearly. The Composite changes with the market every day, which is why nobody circulates a notice when a company joins.

How is the Nasdaq-100 different?

The two names get mixed up, and the rulebooks do not match. The Nasdaq-100, per its methodology, is "designed to measure the performance of 100 of the largest Nasdaq-listed non-financial companies" and uses a modified market capitalization weighting scheme.

• The Nasdaq Composite takes every eligible common stock listed on Nasdaq, with no sector filter. The Nasdaq-100 takes 100 companies and excludes companies classified in the Financial Industry.
• The Composite has no liquidity criterion. The Nasdaq-100 requires a three-month average daily value traded of at least 5 million US dollars.
• The Composite weights by market capitalization. The Nasdaq-100 weights by modified market capitalization, which caps a low-float security's shares at three times its free-floating shares.

Source: Nasdaq, Nasdaq-100 Index methodology, https://indexes.nasdaqomx.com/docs/Methodology_NDX.pdf, read 11 November 2026.

A reader looking at either number should know which rulebook sits behind it, because the Composite's breadth does not make it more spread out. Breadth in the count of stocks and spread in the weights are two different things.

How does one holding decide so much of a day's move?

Weight multiplies move. A holding with a 10 percent weight that falls 5 percent takes 0.5 percent off the index (10 percent × 5 percent = 0.5 percent). The other stocks do not change that sum.

The same arithmetic works on a portfolio-scale amount. The weights below are hypothetical, chosen to show it. Nasdaq publishes the real weights to its index clients behind a login, and this piece does not quote them.

• An investor holds ₹5 lakh in a product that tracks the Composite. A holding at an 8 percent weight puts ₹40,000 into one company (₹5,00,000 × 0.08). A 5 percent fall in that company is a ₹2,000 loss, which is 0.4 percent of the ₹5 lakh.
• The same holding at a 12 percent weight puts ₹60,000 into one company. The same 5 percent fall is a ₹3,000 loss, which is 0.6 percent of the ₹5 lakh.

The difference between 8 and 12 percent is four points of weight, and it moves the loss by half. Only the weights enter the sum, and the count of stocks in the index never does.

A company near the bottom of a cap-weighted index of thousands carries a weight so small that its worst day barely registers in the total. The index is broad in what it holds and narrow in what it depends on.

Why does the Composite matter to an Indian portfolio?

Indian exchanges have closed hours before the Composite does. Nasdaq's methodology says the index is disseminated once per second from 09:30:01 to 17:16:00 ET. Its closing value can change up until 17:15:00 ET because of corrections to last-sale prices.

So an Indian investor reads the Composite's day after it has ended, and reads it as a headline number: down 0.74 percent on a given day. The number tells the investor what a cap-weighted basket of Nasdaq listings did. It does not tell them what any single listing did, and it does not carry any signal about the next session.

A portfolio holding Indian equities, crypto and a global sleeve is exposed to many things at once. A habit worth keeping is to ask what rule sits behind a headline number before reading it as a signal about the whole portfolio. For how a US rate decision travels into an Indian portfolio, the walk-through on how a Fed rate hike reaches an Indian portfolio covers the channel.

What does a rule-based index look like when it caps weights?

A cap-weighted index is one kind of rule. A rule with a cap is another. QSI GEQ8, Qatobit's index of 8 global companies, sets its weights by methodology. The base is free-float market cap adjusted by a quarterly score. Hard caps keep every holding between 3 and 15 percent. It rebalances monthly, with a quarterly composition review, and drift between rebalances is part of how it works.

The contrast sits in the design choice. The Composite lets weights float with price every day. QSI GEQ8 fixes a ceiling and a floor in the methodology and rebalances to them on a schedule. A reader who understands the first rule can tell at a glance what the second one changes.

A published rule can be read before anyone relies on it. For the same idea in crypto, the guide to what a crypto index is sets out what a basket holds and how its weights are set. The piece on concentration risk explains why a few holdings can carry a whole portfolio. When one holding drifts from its weight, the walk-through of rebalancing when one holding falls 10 percent shows the mechanic of bringing it back.

What to take from this

The Nasdaq Composite is broad by eligibility and concentrated by weighting. Every eligible Nasdaq-listed common stock is in. The largest by value decide most of the day's move. Both facts come from the rulebook, and both can be checked on Nasdaq's own pages.

Before reading an index number as a signal about a portfolio, ask what the index holds, how it weights it and how often it changes.

Frequently asked questions

What is the Nasdaq Composite?

The Nasdaq Composite is an index of all eligible domestic and international common stocks listed on the Nasdaq Stock Market, weighted by market capitalization. Nasdaq's methodology sets no size, sector, liquidity or country criterion.

Is the Nasdaq Composite the same as the Nasdaq-100?

No. The Nasdaq-100 holds 100 of the largest Nasdaq-listed non-financial companies and uses a modified market capitalization weighting. The Composite holds every eligible common stock listed on Nasdaq, with no sector filter.

How often does the Nasdaq Composite change its holdings?

Daily. Per Nasdaq's methodology, reconstitution and rebalance both happen every trading day at market open, based on the previous trading day, and Nasdaq makes no announcements for either.

Why do a few stocks dominate a market-cap-weighted index?

Each weight equals a company's share of the total market value. A company worth 600 of a 1,000-unit total carries a 60 percent weight, so its move counts for far more than a smaller company's.

How does a rule-based index differ from a cap-weighted one?

A cap-weighted index lets prices set the weights every day. A rule-based index sets weights by a written methodology, which can include caps and floors, and rebalances to them on a schedule. QSI GEQ8, for example, caps any holding at 15 percent and floors it at 3 percent, and rebalances monthly.

Crypto investments are subject to market risk. Not financial advice.