Jakarta. Indonesian billionaire Prajogo Pangestu saw his fortune shrink by $2.7 billion (Rp 44.89 trillion), or 6.26 percent, to $40.3 billion on Monday after shares of his Barito Group companies tumbled in one of the steepest market sell-offs in recent months.

The decline made Prajogo, Indonesia’s richest man and currently ranked 46th on Forbes' Real Time Billionaires List, the day’s biggest loser among local tycoons. His wealth has now dropped from a recent peak of $48.3 billion recorded on Oct. 11, placing him just below Meta co-founder Eduardo Saverin ($40.5 billion) and CK Hutchison senior adviser Li Ka-shing ($41.3 billion).

Shares of Barito Group firms plunged across the board. Barito Pacific (BRPT) dropped 9.34 percent, Petrindo Jaya Kreasi (CUAN) slid 7.31 percent, and Chandra Daya Investasi (CDIA) fell 5.36 percent. Petrosea (PTRO) plunged 9.44 percent, while Barito Renewables Energy (BREN) slipped 3 percent. Only Chandra Asri Pacific, the group’s petrochemical arm, managed a modest gain of 1.72 percent.

Other Indonesian billionaires also suffered steep losses. Haryanto Tjiptodihardjo, who controls Impack Pratama Industri, the country’s largest maker of polymer-based roofing materials, saw his net worth plunge $1.1 billion (14.73 percent) to $6.3 billion. Hermanto Tanoko, co-owner of Avia Avian, Indonesia’s second-largest paint producer, lost $912 million (12.36 percent), cutting his wealth to $6.5 billion.

Meanwhile, Low Tuck Kwong, owner of coal miner Bayan Resources (BYAN), lost $157 million, but retained his position as Indonesia’s second-richest person with $24.8 billion.

The benchmark Jakarta Composite Index (JCI) fell nearly 2 percent to close at 8,117 on Monday, bucking gains across most Asian markets that rallied on optimism over a potential US–China trade breakthrough later this week.

According to brokerage Pilarmas Investindo, the sell-off was exacerbated by concerns over continued capital outflows, after Bank Indonesia reported foreign investors had withdrawn Rp 940 billion from the domestic financial market between Oct. 20 and 23.

Pilarmas added that weakness in blue-chip and conglomerate stocks intensified the market’s drop, with investors reacting to methodology changes in the MSCI Index’s constituent review, particularly the revised calculation of free float adjustments for Indonesian equities.

Muhammad Wafi, head of research at KISI Sekuritas, said conglomerate stock valuations had become too expensive after months of steep gains. “Investors are locking in profits as they see limited upside,” Wafi said. “This is a cooling-off phase rather than the start of a long-term bear market. The correction is a natural reaction after extreme rallies.”