IDX Plans to Remove Concentrated-Ownership Shares From Its Main Index

Daily IntELigence Brief | 20 October 2026

Implications: High — Indonesian issuers and investors using the Jakarta Composite Index. The planned exclusion would change how the domestic benchmark is calculated and may require funds tracking it to review their holdings. It does not resolve MSCI’s separate proposal to remove Indonesia from its emerging-market indexes.

Summary: On 19 October, the Indonesia Stock Exchange (IDX) announced that it plans to exclude shares classified as having High Shareholding Concentration (HSC) from the Jakarta Composite Index (IHSG). IDX says 80 such shares currently account for about 18% of the index’s weight; it has not announced an effective date. ANTARA’s account of the IDX director’s announcement.

Context: The 16 October brief covered MSCI’s consultation on moving Indonesia from Emerging Market to Standalone status; the 19 October follow-up covered the market sell-off and temporary trading-limit change. Today’s new step is IDX’s proposed change to its own index and ownership disclosures, announced after a meeting with MSCI. IDX did not disclose the meeting’s conclusions. ANTARA.

What changed. IDX’s president director said HSC shares will cease to contribute to IHSG calculations but will remain listed and tradable. IDX also plans to identify whether shareholders holding at least 1% are affiliated with an issuer. IDX said it would announce when the changes take effect. ANTARA on the index change; ANTARA on both initiatives.

Why it matters. Once implemented, the index change would alter the benchmark against which Indonesian equity performance is measured. Managers whose mandates track IHSG may need to assess rebalancing; the scale of any sales cannot be inferred from the shares’ 18% index weight alone. The added affiliation disclosure could help investors assess control and free float. These are prospective commercial effects. MSCI has said it wants evidence of consistent implementation and sustained impact from Indonesia’s reforms, and its reclassification decision remains pending. MSCI’s consultation.

What to watch. IDX’s formal implementation notice, effective date and revised index methodology; subsequent investor feedback; and MSCI’s response during its consultation. ANTARA; MSCI.

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Image illustration credit: AI-generated editorial illustration of market ownership disclosures.