Indonesian stocks experienced a sharp decline on Friday, marking the largest one-day drop since the 1998 Asian financial crisis, following an announcement from MSCI that it is considering a significant downgrade of Indonesia’s market classification. The Jakarta Composite Index fell more than 11 percent at one point, triggering a temporary halt in trading due to heightened volatility. The index has now lost nearly 40 percent of its value this year, placing it among the world’s worst-performing stock markets.

MSCI announced on Thursday that it had initiated a consultation on whether to downgrade Indonesia’s status from an “emerging market” to “stand-alone,” a move more severe than the previously considered one-level downgrade to “frontier market.” Downgrading to stand-alone status would effectively remove Indonesia from all MSCI indexes, which guide investment portfolios worth trillions of dollars globally. This would isolate the country’s market in a category reserved for nations experiencing significant economic or political turmoil.

The announcement took market participants by surprise. Gary Tan, a portfolio manager at Allspring Global Investments in Singapore, described the move as more severe and earlier than expected. Previously, MSCI had planned to assess Indonesia’s market next month, prompting investors to question the timing of the current consultation.

Indonesia’s Financial Services Authority, led by Friderica Widyasari Dewi, acknowledged MSCI’s assessment and expressed commitment to implementing reforms. Dewi emphasized Indonesia’s economic fundamentals, such as its large population of nearly 290 million, membership in the Group of 20, and standing as Southeast Asia’s largest economy. She highlighted the country’s role as a major producer and exporter of key commodities, including palm oil, nickel, thermal coal, copper, and natural gas, noting its importance in global supply chains, especially those related to electric vehicles and green energy.

MSCI cited persistent market dysfunction and governance issues as the basis for considering the downgrade beyond the frontier market level. The index provider stated that feedback from investors indicated that a one-step downgrade would not adequately capture the extent of the challenges facing Indonesia's market. It said the consultation would proceed unless evidence emerges showing significant improvements before a final decision, expected by the end of June next year.

A downgrade to stand-alone status could force global funds that track MSCI indexes to divest Indonesian stocks, potentially draining liquidity at a time when investor confidence is already fragile. The fallout may also pressure the rupiah, which breached 18,000 to the dollar on Friday. Indonesia’s central bank reportedly intervened to support the currency and reassured that its foreign exchange reserves, exceeding $146 billion, remain adequate to manage the situation.

The warning poses a notable challenge for President Prabowo Subianto and Finance Minister Suahasil Nazara, who recently took office amid concerns over economic management and populist policies perceived to be increasing state control and fiscal strain. Officials at the Indonesia Stock Exchange expressed surprise at the MSCI announcement but indicated a focus on reinforcing fundamental market reforms.

Despite the immediate market turmoil, some analysts noted that Indonesia’s bond and currency markets remained relatively stable, suggesting limited contagion beyond equities at this stage. The coming months will be critical for Indonesia as it seeks to address concerns raised by MSCI and restore investor confidence in its financial markets.