Glossary
Nasdaq-100
An index of about 100 of the largest non-financial companies listed on the Nasdaq, weighted by modified market cap.
The Nasdaq-100 is a stock index of roughly 100 of the largest non-financial companies listed on the Nasdaq exchange, including US and some foreign issuers. Its ticker is NDX. It is heavily weighted toward technology, communication services and consumer companies, and through funds that track it, such as the Invesco QQQ Trust, it is one of the most traded benchmarks in the world.
How it is built
- Eligibility: the company must be listed on Nasdaq and must not be a financial company, so banks, insurers and similar firms are excluded even if they are large.
- Weighting: by modified market capitalization. Larger companies get bigger weights, but caps limit how much any single company, or the biggest group of companies combined, can make up.
- Maintenance: membership is reconstituted once a year in December, with quarterly rebalancing of weights. In 2026 Nasdaq changed the methodology, adding a weight adjustment for companies with low free float and a fast-entry rule for very large new listings.
How it differs from other indexes
The Nasdaq-100 is narrower than the Nasdaq Composite, which includes nearly every Nasdaq-listed stock, financials included. Compared with the S&P 500 it leaves out NYSE-listed companies and all financials, and it carries a heavier technology weight, so it has tended to rise more in tech rallies and fall harder in tech sell-offs.