Answer

A constituent is a member or component of an index or average like the Dow, Nasdaq. To access historical constituents of major indices in the U.S. and worldwide:

Finaeon (formerly Global Financial Data) for current and historical constituent lists (including S&P 500) of Major US Indices and GFD Foreign Indices.

Geography: U.S. worldwide

LSEG Workspace (formerly Refinitiv)

Geography: U.S. worldwide

1. Locate the target index by
   1. Use the index name, e.g. FTSE, to locate the specific index you're interested in
   2. Or in the Advanced Search (type AS in the search bar), select "Indices" from the UNIVERSE drop-down list.
2. Navigate to the "Constituents" tab and choose "Leavers and Joiners" from the dropdown list.
3. You will find a comprehensive list of all historical constituent companies that have been part of this index (since 1994)

Datastream via LSEG Workspace (DFO)

Geography: U.S. worldwide

1. Open Excel and login to Refinitiv
2. Open Datastream - Datastream Formula
3. You can only retrieve historical constituents in Datastream is by monthly. Where historical data is available, the latest month end could be display by entering  L + DS mnemonic + MMY. For example, for NDX, you may use LNASA1001222 for December 2022 data.