Jakarta. Indonesia Stock Exchange (IDX) has revised its High Shareholding Concentration (HSC) methodology and expanded the watchlist to 51 stocks, marking the latest step in a series of market reforms following MSCI's concerns over Indonesia's market accessibility earlier this year.

The revised methodology introduces a new price impact ratio criterion for stocks with market capitalizations above Rp 10 trillion ($554.6 million), in addition to the existing assessment of concentrated ownership for both scrip and scripless shares.

"The new criterion measures the extent of a stock's price movement relative to its trading activity, or velocity," IDX Corporate Secretary Kautsar Primadi Nurahmad said in a statement on Wednesday.

Velocity measures trading activity by comparing the average trading volume with a company's public free-float shares. The new price impact ratio will be calculated every quarter, while surveillance trigger factors based on market supervision will continue to be applied on an incidental basis.

Following the revision, 37 additional stocks have been classified as HSC, bringing the total number of stocks on the watchlist to 51.

The HSC list is intended as a market transparency tool rather than a regulatory sanction. Stocks included on the list are not deemed to have violated listing rules but are considered to have ownership structures that may limit liquidity and amplify price movements because a large portion of shares is held by a small group of investors.

The methodology update forms part of a broader overhaul of Indonesia's capital market after global index provider MSCI raised concerns earlier this year over market transparency, concentrated ownership, and the risk of price distortions. In response, Indonesian authorities have introduced reforms including tighter ownership disclosure requirements, a higher minimum free-float requirement, and the publication of the HSC list to improve market quality and strengthen investor confidence.

IDX said the enhanced HSC criteria are expected to help investors better understand the trading characteristics of listed stocks while reinforcing the exchange's commitment to building a more transparent, credible, and globally competitive capital market.

The 51 Stocks currently classified as HSC are:

1. Samator Indo Gas (AGII)
2. Barito Renewables Energy (BREN)
3. Dian Swastatika Sentosa (DSSA)
4. Ifishdeco (IFSH)
5. Panca Anugrah Wisesa (MGLV)
6. Abadi Lestari Indonesia (RLCO)
7. Rockfields Properti Indonesia (ROCK)
8. Satria Mega Kencana (SOTS)
9. BSA Logistics Indonesia (WBSA)
10. Transcoal Pacific (TCPI)
11. Mahkota Group (MGRO)
12. Kota Satu Properti (SATU)
13. Delta Giri Wacana (DGWG)
14. Habco Trans Maritima (HATM)
15. DCI Indonesia (DCII)
16. Bayan Resources (BYAN)
17. Indoritel Makmur Internasional (DNET)
18. Ekamas Mora Republik (MORA)
19. Sejahteraraya Anugrahjaya (SRAJ)
20. Bank Permata (BNLI)
21. Bank Ina Perdana  (BINA)
22. Pradiksi Gunatama (PGUN)
23. Soho Global Health (SOHO)
24. Jaya Sukses Makmur Sentosa (RISE)
25. FAP Agri (FAPA)
26. Siloam International Hospitals (SILO)
27. Krom Bank Indonesia (BBSI)
28. Bank SMBC Indonesia (BTPN)
29. Siantar Top (STTP)
30. Multipolar Technology (MLPT)
31. Golden Energy Mines (GEMS)
32. Global Digital Niaga (BELI)
33. Maha Properti Indonesia (MPRO)
34. Famon Awal Bros Sedaya (PRAY)
35. Sinar Mas Agro Resources and Technology (SMAR)
36. Cemindo Gemilang (CMNT)
37. Metropolitan Kentjana (MKPI)
38. Perdana Bangun Pusaka (KONI)
39. Yupi Indo Jelly Gum (YUPI)
40. Hotel Fitra International (FITT)
41. Ancara Logistics Indonesia (ALII)
42. Hoffmen Cleanindo (KING)
43. MD Entertainment (FILM)
44. Pelayaran Nasional Ekalya Purnamasari (ELPI)
45. Golden Flower (POLU)
46. MSIG Life Insurance Indonesia (LIFE)
47. Prima Andalan Mandiri (MCOL)
48. Bank Maybank Indonesia (BNII)
49. Allo Bank Indonesia (BBHI)
50. Bank Mega (MEGA)
51. Citra Marga Nusaphala Persada (CMNP)