IDX Changes HSC Calculation Methodology, Expanding the List

Jakarta, CNBC Indonesia — The Indonesia Stock Exchange (IDX) has outlined a new methodology for calculating high shareholding concentration (HSC), which refers to listed companies with highly concentrated share ownership.

IDX President Director Jeffrey Hendrik said the HSC committee had decided that the methodology would be made public. The previous methodology, which applied a threshold to shares with a market capitalisation above Rp5 trillion, will no longer be used.

“This means HSC screening will cover the entire market and all listed shares,” he said at a press conference at the IDX building on Tuesday (10 November 2026).

The previous HSC calculation included the price impact ratio (PIR), an advanced liquidity measure of a stock’s ability to absorb trading volume without significant price movements.

A lower PIR indicates that a stock can absorb trading volume more effectively. Under the new HSC calculation methodology, PIR will no longer be taken into account.

Jeffrey said this meant the HSC calculation would not have to wait for share prices to move. “The committee has therefore decided that shares held by 10 or fewer shareholders, who collectively own 92.5% or more, will be included in the HSC,” he said.

Under the new methodology, the HSC Committee will soon announce an updated list of HSC shares. Jeffrey said the list would include 383 shares, adding 300 new stocks to the HSC category. “That represents an additional 6.16% of the JCI’s market capitalisation,” he said.

Under the previous calculation methodology, 83 listed companies were classified as HSC. The HSC share policy took effect on 2 April 2026.