FTSE All-Share index constituents and returns (licensed)

Licensed: not exercised here

FTSE All-Share index data is a paid licensed product (FTSE Russell), so it carries no provenance badge: the access path below was not run in this session. Treat it as unverified until someone exercises it through a licensed FTSE Russell feed or a redistributor. This is the honest grade under the institute’s Verified discipline.

The FTSE All-Share is the headline broad UK equity index, the union of the FTSE 100, FTSE 250, and FTSE SmallCap, and it serves as the investable universe for most UK equity research: index membership, free-float market capitalisation, and daily total returns. A paper we distill uses it: Becht, Franks & Wagner use the FTSE All-Share as the eligible-stock universe (the index held between roughly 353 and 703 firms over their 2007 to 2015 sample), taking market capitalisation and daily returns as controls when studying private meetings between an active asset manager and its UK portfolio firms.

• Cost: licensed, subscription. No free download of historical constituents.
• Vendor: FTSE Russell (part of LSEG); often reached through redistributors such as Datastream or WRDS.
• Coverage: UK-listed equities meeting the FTSE size and liquidity rules, with membership, market cap, and returns; long daily history.

Access (when licensed)

• Through FTSE Russell or a redistributor. Membership and index returns come from a FTSE Russell licence directly, or via Datastream / Refinitiv / WRDS where the institution carries the feed. Check which route is available.
• Keyed by security and date. A point-in-time constituent extract gives the membership set and free-float market cap on each date; pair with the security’s return series.
• Terminal or API credentials are required. Keep any credentials in .env, never hard-coded.

Gotchas (the ones that bite pipelines)

These are the failure modes to expect; they are documented, not verified here.

• Use point-in-time membership, not today’s list. Constituents change at quarterly reviews and via fast-entry / corporate-action rules; reconstructing the universe from the current membership induces survivorship and look-ahead bias. The citing paper’s universe swings from roughly 353 to 703 firms over the sample for exactly this reason. Pull the historical constituent set.
• Free-float weighting, not full market cap. FTSE weights by investable free float, so the index market cap differs from full shares-outstanding market cap; using the wrong one misweights any value-weighted measure. Match the cap concept to the question.
• Price versus total return. The price index and the total-return index differ by reinvested dividends; performance and event-study work need the total-return series. State which you used.
• Identifier mapping for cross-data joins. Linking FTSE constituents to accounting or holdings data requires mapping SEDOL / ISIN to the other source’s identifiers across listing changes and dual lines; the join has known mismatches. Verify it.
• Overlap with the sub-indices. The All-Share is the union of FTSE 100 / 250 / SmallCap; double-counting or gaps appear if you splice the sub-indices instead of taking the All-Share membership directly. Use the All-Share list.

Citation

Cite the index provider, e.g.: FTSE All-Share Index (FTSE Russell / LSEG), accessed YYYY-MM-DD. State whether membership, market cap, or returns were used, the cap concept (free-float versus full), and the point-in-time date range.