IDX has announced that stocks classified as having high shareholding concentration (HSC) will be excluded from the JCI calculation. The measure concerns how the index reflects shares available to the market and can influence index movements. Exclusion from an index is not delisting: the shares remain listed and tradable.

Why concentration matters

When a large portion of a company's shares is held by a small number of investors, the freely traded portion may be more limited. In some cases, price moves in those shares can have an outsized effect on an index. IDX says HSC criteria consider ownership concentration, a price impact ratio, and surveillance concerns. The status is reviewed periodically, and a stock may return to the calculation if it no longer meets the criteria.

What should investors take away?

A methodology change can alter an index's level and composition without automatically changing a company's fundamentals. Investors should not assume that a post-adjustment rise in the JCI means gains are broad across the market. Review market breadth, trading value, fund flows, liquidity, ownership concentration, and each company's business performance.

Refer to IDX announcements for the effective date and technical index adjustments. A stock's price direction cannot be inferred solely from its removal from the JCI calculation.

Sources: Bisnis.com, October 20, 2026; Bisnis.com, October 19, 2026.