Flooring Guide by Cinvex — The Indonesia Stock Exchange (IDX) has updated its list of securities flagged for High Shareholding Concentration (HSC). As of early June 2026, the regulatory body has added two new stocks to this growing list, bringing the total number of companies with highly concentrated ownership to 12 since the initiative began.
The latest additions to the HSC list are PT Mahkota Group Tbk. (MGRO) and Transcoal Pacific Tbk. (TCPI). According to official disclosures, the IDX identified that MGRO’s ownership is significantly centralized, with its primary shareholders controlling 93.76% of the company’s total issued shares as of May 26, 2026. Similarly, TCPI has reported a high concentration level, with major stakeholders holding 94.10% of its shares.
The IDX clarified that its methodology for determining these levels involves analyzing the total structure of script and non-script share ownership. This screening process is intended to provide greater transparency regarding market liquidity and ownership distribution, which can be critical factors for investors monitoring these specific equities.
While some issuers identified in the HSC list have reached out to the exchange to request audiences, the response from the corporate side remains measured. Jeffrey Hendrik, Acting President Director of the IDX, noted that as of mid-May 2026, no companies on the HSC list had initiated corporate actions aimed at increasing their free float ratios—a move that would typically reduce concentration levels. Furthermore, no issuers have formally requested a re-screening from the exchange.
“To date, we have not received any reports that these companies have implemented changes to their ownership structures, nor have they requested a formal re-evaluation of their status,” Hendrik stated during a press briefing at the IDX office in Jakarta.
Below is the current list of stocks identified with High Shareholding Concentration as of the latest regulatory update:
| No. | Ticker | HSC Percentage | Calculation Date |
|---|---|---|---|
| 1 | MGRO | 93.76% | May 26, 2026 |
| 2 | TCPI | 94.10% | May 25, 2026 |
| 3 | WBSA | 95.82% | May 7, 2026 |
| 4 | BREN | 97.31% | May 31, 2026 |
| 5 | DSSA | 95.76% | March 31, 2026 |
| 6 | RLCO | 95.35% | March 31, 2026 |
| 7 | ROCK | 99.85% | March 31, 2026 |
| 8 | MGLV | 95.94% | March 31, 2026 |
| 9 | IFSH | 99.77% | March 31, 2026 |
| 10 | SOTS | 98.35% | March 31, 2026 |
| 11 | AGII | 97.75% | March 31, 2026 |
| 12 | LUCY | 95.47% | March 31, 2026 |
Summary
The Indonesia Stock Exchange (IDX) has expanded its High Shareholding Concentration (HSC) list to 12 companies as of June 2026. The latest additions include PT Mahkota Group Tbk. (MGRO) and Transcoal Pacific Tbk. (TCPI), which report ownership concentration levels of 93.76% and 94.10%, respectively. This regulatory initiative aims to increase market transparency regarding share liquidity and ownership distribution.
Despite the designation, IDX officials report that none of the identified issuers have taken formal steps to increase their free float ratios or requested a status re-evaluation. The list identifies companies where primary shareholders maintain dominant control, serving as a critical resource for investors monitoring stock concentration. No corporate actions to adjust these ownership structures have been formally reported to the exchange.