Direct Answer
The Hang Seng Composite Index is a rule-based measurement of broad Hong Kong equity benchmark, maintained by Hang Seng Indexes. Like every index it owns nothing: it is a number produced by applying a published weighting formula to a selected list of companies, revised on a schedule the provider sets.
What this index covers
The Hang Seng Composite Index covers broad Hong Kong equity benchmark, within the Hong Kong market. Hang Seng Indexes defines which securities are eligible, how they are selected from that pool, and how much each one contributes to the published number.
The index name does not state a fixed company count, so the number of constituents follows the eligibility rules rather than a target.
How constituents are weighted
Freefloat adjusted market capitalisation weighted with a 10% cap on individual securities and a 5% aggregate cap on foreign companies. Excess foreign company weight is redistributed to the remaining constituents in proportion to their weightings.
The weighting method is the single biggest driver of how an index behaves. Two indexes covering the same market can diverge for years purely because they weight differently, which is why comparing index levels without knowing the method tells you very little.
What qualifies for inclusion
HKEX Main Board shares and depositary receipts of companies incorporated or mainly operating in Greater China, REITs and qualifying stapled securities, plus primary listed one share one vote foreign companies. Chapter 21 investment companies and companies with high shareholding concentration are excluded. A security must rank within the top 95% of cumulative market value and pass a turnover velocity test of 0.05% in at least 10 of the past 12 months.
Eligibility rules are the part of an index most readers never look at and the part that decides what it can possibly measure. A screen that excludes a whole sector, or admits only one listing venue, shapes the result far more than any day of trading does.
How long a listing must exist first
No listing history is required: new issues listed before the review cut-off date are considered in the review.
A seasoning rule is why a large new listing does not appear in an index the week it starts trading. It is a deliberate lag, and it means an index can under-represent a fast-growing part of the market for months at a time.
When the membership is revised
Reviewed half-yearly with data cut-off at the end of June and December, effective the next trading day after the first Friday of September and March. Buffer zone: existing constituents ranked below the top 96% of cumulative market value are removed, and non-constituents within the top 94% are included. Free float factors and caps are updated quarterly.
Reconstitution is the one date an index changes shape by design rather than by price. Funds tracking it have to trade toward the new membership, which is why the schedule matters to anyone holding the tracker rather than only to the provider.
The rule that surprises people
The number of constituents is variable with no limit, because the index targets the top 95% of cumulative market capitalisation rather than a set count. Each listed share class of a company is treated as a separate security.
References
- Hang Seng Indexes: Hang Seng Indexes Company, For Managing the Hang Seng Composite Index Series (index methodology), as published 2025. Every rule described on this page is taken from this document.
Current Hang Seng Composite Index constituents
Hang Seng Indexes publishes and licenses the Hang Seng Composite Index constituent list. Swoopr does not republish it here. The provider's own page is the authoritative source for current membership and weights.
Related reading
- All stock market indexes: how indexes are built, weighted and revised.
- Asia-Pacific indexes: others covering the same region.
- Index concentration: measuring how much of an index sits in its largest holdings.
- Index rebalancing and inclusion effects: what happens to a stock when index membership changes.
Frequently Asked Questions
Who maintains the Hang Seng Composite Index?
Hang Seng Indexes maintains the Hang Seng Composite Index and publishes the methodology document that defines its eligibility and weighting rules.
What does the Hang Seng Composite Index measure?
It measures broad Hong Kong equity benchmark. The index is a calculated number applying a weighting formula to a selected list of companies, and it holds nothing itself.
Where can I see the current Hang Seng Composite Index constituents?
Hang Seng Indexes publishes the current constituent list. Swoopr does not republish it, because index providers license constituent data and Swoopr holds no such licence.