Nasdaq-100 Index

The **Nasdaq-100 Index** is a rules-based, modified market-capitalization-weighted index designed to measure the performance of 100 of the largest non-financial companies primarily listed on a Nasdaq-affiliated U.S. exchange. It includes U.S. and international issuers, excludes companies classified in the financial industry, and is maintained by Nasdaq Global Indexes under published eligibility, selection, weighting, and review rules. ^[1][2]

Purpose and history

The Nasdaq-100 launched on January 31, 1985. It was introduced alongside the Nasdaq Financial-100, which covered financial companies listed on Nasdaq; the Nasdaq-100 was designed to represent the non-financial group. Nasdaq described the original indexes as intended to focus attention on their constituent companies and provide a basis for potential index products. ^[3]

The Nasdaq-100 is distinct from the Nasdaq Stock Market and from the Nasdaq Composite Index. The Stock Market is an exchange; an index is a calculated measure that tracks a defined group of securities. The Nasdaq Composite covers a much broader set of Nasdaq-listed common stocks, whereas the Nasdaq-100 focuses on a selected group of large non-financial issuers. The two indexes can therefore move differently and should not be treated as interchangeable measures of the exchange or of the entire U.S. stock market. ^[3]

The index is used as a market benchmark and as the basis for financial products. Nasdaq’s materials describe products tied to it across exchange-traded products, mutual funds, separately managed accounts, and insurance products. The index itself is a calculation, not a company, security, or investment fund: it cannot be purchased directly. A fund or other product that tracks it is a separate instrument, with its own structure, costs, trading characteristics, and tracking results. ^[3][4]

Constituents and eligibility

The index is intended to include 100 of the largest eligible non-financial companies listed primarily on a U.S. Nasdaq-affiliated exchange. Nasdaq’s methodology permits eligible common stocks, tracking stocks, and American Depositary Receipts (ADRs), subject to the applicable rules. Companies classified in the financial industry under the Industry Classification Benchmark are excluded. Real estate companies may qualify if they are not organized as real estate investment trusts (REITs); REITs and special purpose acquisition companies (SPACs) are among the excluded security types. ^[1]

Eligibility is not determined by size alone. The methodology sets listing and security criteria and specifies how eligible issuers’ market capitalization is calculated. It distinguishes between direct listings and different types of ADRs, and it addresses companies with multiple eligible share classes. For constituent selection, Nasdaq uses full market capitalization under the definitions in the methodology; for weighting, it uses a modified market-capitalization approach. Consequently, an issuer’s rank for selection and its eventual weight in the index are related but are not identical measures. ^[1]

The index is not restricted to companies incorporated in the United States. Nasdaq’s fact sheet describes it as containing large domestic and international non-financial companies listed on the Nasdaq Stock Market. The relevant connection is the listing and eligibility framework, rather than U.S. incorporation alone. This means the index may include foreign issuers whose eligible securities meet its rules. ^[2]

The name “Nasdaq-100” refers to companies, but the number of individual securities may differ from 100. When a constituent company has more than one eligible listed share class, multiple securities can be represented. Nasdaq’s fact sheet, for example, reports 100 companies while listing 101 securities. That distinction helps explain why a constituent list can contain more securities than the index’s name might suggest. ^[1][2]

Weighting and calculation

The Nasdaq-100 uses modified market-capitalization weighting. In an ordinary capitalization-weighted index, larger companies generally have larger weights in proportion to their market value. A modified approach applies additional rules to the weights, so the final proportions are not simply each company’s market value divided by the combined market value of all constituents. Nasdaq’s methodology defines the adjustments and weighting process; the detailed rules should be consulted for the relevant methodology version. ^[1]

Because it is weighted rather than equal-weighted, the index’s return can be influenced disproportionately by its largest-weighted constituents. Company prices, shares used in index calculations, constituent changes, and weighting adjustments can all affect the aggregate result. The index is therefore not a measure of the average return of 100 equally weighted companies. Its sector and issuer exposures reflect both which companies qualify and how the weighting rules allocate index weight among them. ^[1][2]

Nasdaq publishes distinct index variants. Its fact sheet identifies NDX as the price-return index and XNDX as the total-return index, with a separate net-total-return ticker also identified. Price-return and total-return calculations differ in how distributions are treated, so a reported return should be interpreted in light of the specific version and measurement period. ^[2]

Maintenance and methodology

Index membership and weights are not fixed permanently. Nasdaq’s methodology describes rules for eligibility, constituent selection, index maintenance, and weighting. The provider also publishes methodology documents and materials about consultations and revisions. Nasdaq states that significant changes to the methodology may follow a formal consultation process; it reported implementing targeted updates to the Nasdaq-100 methodology on May 1, 2026. ^[1][5]

A methodology revision can change how eligibility or market capitalization is assessed without changing the index’s broad objective: measuring the performance of 100 of the largest Nasdaq-listed non-financial companies. The operative methodology is therefore important when describing current selection criteria. Historical summaries and older product guides may reflect earlier rules; where they differ from the current published methodology, the current methodology is the principal reference for present eligibility and calculation. ^[1][5]

Changes in the index can affect products that seek to track it. When constituents or weights change, a tracking fund may need to adjust its holdings or use other techniques to reflect the revised benchmark. Such trading may occur around announced implementation dates. The index’s rules define benchmark composition, but do not prescribe how every product must replicate it; implementation depends on the individual product’s prospectus and operating arrangements. ^[1][4]

Interpretation and limitations

The Nasdaq-100 is often used to discuss the performance of large companies listed on Nasdaq, particularly companies in technology and other growth-oriented industries. However, the index is not a pure technology index: eligibility is defined by exchange listing, company size, and industry exclusions, not by a technology-only mandate. Nasdaq’s fact sheet lists several industry groups, including technology, consumer discretionary, health care, industrials, telecommunications, and others. Sector composition and constituent weights change over time, so any snapshot should be dated. ^[2]

Its concentration in a relatively limited number of issuers and its exclusion of financial companies distinguish it from broader market benchmarks. These characteristics can result in performance that differs substantially from indexes with different eligibility rules, sector representation, or weighting systems. The index’s historical returns are not a forecast, and its past composition may differ considerably from its current composition. Comparisons should specify the period, return variant, currency, and benchmark methodology being used. ^[1][2]

The Nasdaq-100 also measures securities listed on Nasdaq rather than all publicly traded U.S. companies. A large company listed primarily on another exchange may not qualify, even if it is comparable in size to an index constituent. Conversely, an eligible international issuer may qualify if it meets Nasdaq’s requirements. Thus, index membership reflects both company characteristics and the venue on which its eligible securities are listed. ^[1]

Relationship to investment products

Funds and other products may use the Nasdaq-100 as a benchmark or seek to track its performance. Such products are not identical to the index: they may incur fees and transaction costs, hold cash, use sampling or other replication methods, and experience tracking differences. An index level is a calculated benchmark value, while a fund share is a tradable security with its own price and legal structure. Nasdaq describes the index as the basis for a range of investment vehicles, including exchange-traded products and mutual funds. ^[3][4]

Investors, analysts, and financial institutions may use the index to compare portfolio performance, describe market segments, or develop products linked to its movements. These uses do not make the index a comprehensive representation of the economy or of all U.S. equities. Its defined selection rules, non-financial-company focus, Nasdaq listing requirement, and modified capitalization weights determine what it represents and what falls outside its scope. ^[1][3]