Jakarta. Indonesia’s benchmark index tumbled on Thursday as geopolitical jitters spiked after Donald Trump signaled an imminent escalation in the US–Iran conflict, dragging regional markets lower and pushing oil prices sharply higher.

Jakarta Composite Index (JCI) dropped 2.19%, or 157 points, to close at 7,026. The index moved within a range of 7,019–7,161 during the second session.

Trading activity remained heavy, with volume reaching 25.4 billion shares and turnover at Rp 12.5 trillion ($735 million), across more than 1.7 million transactions. Decliners far outnumbered gainers, with 530 stocks falling, 177 advancing, and 113 unchanged.

Top gainers were led by Alakasa Industrindo (ALKA), which surged 24.83%, followed by MNC Studios International (MSIN) rising 24.63%, Jobubu Jarum Minahasa (BEER) gaining 21.71%, and Yanaprima Hastapersada (YPAS) jumping 20.35%.

On the losing side, Nusantara Sawit Sejahtera (NSSS) dropped 14.89%, Remala Abadi (DATA) fell 14.84%, Wijaya Cahaya Timber (FWCT) declined 14.81%, and Trimitra Prawara Goldland (ATAP) slipped 14.77%.

Pilarmas Investindo Sekuritas attributed the sharp decline to Trump’s remarks, which reignited concerns over a broader military escalation involving Iran. The US president said Washington could launch further attacks within the next two to three weeks, signaling a heightened risk of prolonged conflict.

Trump said in a Wednesday night address that the United States would “finish the job” in Iran soon as “core strategic objectives are nearing completion,” suggesting military operations could wrap up in the near term.

“We are going to hit them extremely hard over the next two to three weeks. We’re going to bring them back to the Stone Ages, where they belong,” Trump said.

However, Trump stopped short of providing clarity on a previously suggested deadline for Iran to reopen the Strait of Hormuz, a vital route for global oil and gas shipments, nor did he outline a clear path to ease ongoing supply disruptions that have driven energy prices higher.

Pilarmas said the lack of a clear de-escalation pathway has heightened uncertainty and eroded market confidence.

“Lack of a clear de-escalation path has once again triggered geopolitical concerns,” Pilarmas wrote in its research on Thursday.

The brokerage added that rising oil prices, fueled by the conflict, have intensified global inflation concerns, reinforcing expectations of tighter monetary policy and weighing on equities.

Pilarmas also noted that investors are likely to remain cautious, with volatility expected to persist in the absence of a confirmed ceasefire involving the US, Israel, and Iran.

“The market is highly sensitive to the latest developments, particularly Trump’s speech, which has proven to significantly impact both global and domestic financial markets,” it added.

Across the region, Asian markets declined in tandem. Japan’s Nikkei 225 fell 2.4% to 52,463, while South Korea’s Kospi dropped 4.5% to 5,234 after data showed March consumer prices rose 2.2% year-on-year, driven by higher fuel costs.

Hong Kong’s Hang Seng slipped 1.3% to 24,965, and China’s Shanghai Composite Index edged down 0.9% to 3,913.

Oil prices surged following Trump’s remarks. Brent crude jumped 6.9% to $108.15 per barrel, while US benchmark crude rose 6.4% to $106.55.

“The market has shown disappointment because the speech President Trump made was far less than what the market expected,” said Takashi Hiroki.

“There were no concrete details about the end of the hostilities with Iran. What the market wants is a clear outline for the ceasefire,” he said.

On Wednesday, Wall Street closed higher, with the S&P 500 gaining 0.7% to 6,575. The Dow Jones Industrial Average rose 0.5% to 46,565, while the Nasdaq Composite climbed 1.2% to 21,840.