Index guideChina

The Shanghai Composite

Every company on one exchange, weighted by total market value rather than tradeable shares — which means the index measures ownership that largely cannot be bought.

1991Launched

2,000+Constituents

Total capWeighting basis

All listedSelection

The SSE Composite launched in July 1991 with a base value of 100, covering every company listed on the Shanghai Stock Exchange. There is no selection rule beyond the listing itself, which makes it structurally similar to the Nasdaq Composite — an exchange census rather than a curated benchmark.

Its distinguishing feature is not breadth, though. It is who owns the shares.

The free float problem

Listed value versus tradeable valueWhy the distinction matters here

Most modern benchmarks weight by float-adjusted capitalization for exactly this reason. The SSE Composite's use of total capitalization is a legacy design choice with real consequences.

Many of the largest Shanghai-listed companies are state-controlled banks, energy groups and industrial enterprises where a substantial portion of shares sits with government entities and does not trade. Weighting by total market value gives those companies index influence that no outside investor could actually take on.

The practical consequence: the index can be driven by companies whose tradeable shares are a small fraction of their headline size. Anyone using it as a portfolio template is looking at something they cannot replicate.

Share classes

Chinese listings historically split into A-shares, denominated in renminbi and originally restricted to domestic investors, and B-shares, denominated in foreign currency. Access for foreign investors has been progressively opened through quota programs and the Stock Connect links with Hong Kong, but the market remains more segmented than any other major venue covered here.

This matters for index construction. Global index providers phased mainland A-shares into their emerging-market benchmarks gradually and at partial inclusion factors, precisely because full access was not available.

Shanghai is not the whole of mainland China. The Shenzhen exchange hosts a different mix — smaller, more private, more technology-oriented — and both rank among the world's largest exchanges by listed value. The CSI 300, which spans both, is often the more useful single read on mainland equity.

Facts worth knowing

Base value 100, July 1991The exchange itself had reopened only months earlier, after four decades of closure.
Retail participation is unusually highIndividual investors account for a far larger share of turnover than in developed markets, which contributes to the index's volatility.
Trading halts are structuralIndividual stocks operate under daily price limits, so an index move can understate the pressure in the underlying market on extreme days.
Policy is a market factorRegulatory and state direction affect listed companies more directly than in most markets, and the index responds accordingly.
Composite means compositeThere is no committee and no eligibility screen. Listing on the exchange is the entire criterion.

Common questions

Can foreign investors buy the Shanghai Composite?

Access to mainland A-shares runs through quota programs and the Stock Connect scheme rather than open direct purchase. Most foreign exposure comes through funds tracking broader mainland indexes.

Why is it so volatile?

High retail turnover, daily price limits that defer rather than absorb pressure, and sensitivity to policy announcements all contribute.

Shanghai or Shenzhen?

Different markets with different characters. The CSI 300 covers the largest companies across both and is generally the better single benchmark for mainland equity.

PillarMajor stock indexes of the worldCompareHang Seng IndexSame structureNasdaq Composite