Singapore's Straits Times Index fell 5.3% in October, the biggest monthly drop among Southeast Asia's major benchmarks outside Indonesia, as a global selloff in technology shares reached the region's most liquid market. The STI closed Oct. 30 at 5,376.74, down from 5,675.88 at the end of September, according to Capital Times calculations from Yahoo Finance data.

The losses were spread across the region. Indonesia's Jakarta Composite Index plunged 16.7% to 5,057, Kontan reported. Thailand's SET Index fell 2.6% as overseas funds sold, Malaysia's FBM KLCI lost 2.2%, and the Philippine Stock Exchange index ended near its lowest level in almost a year. For investors who had piled into Southeast Asia earlier in 2026, October showed how closely these markets still trade with U.S. tech sentiment and global bond yields, even where local economies keep growing.

Singapore: tech counters take the hit

The Singapore Exchange on Monday described the month as a "broad but uneven" correction, The Business Times reported. The STI's total return, which includes dividends, was minus 5.2%, and the index spent the last 16 sessions of the month mostly between 5,370 and 5,450. The iEdge Singapore Next 50 Index, which tracks the next tier of companies by size, fell 6.8%.

Most of the damage came early. The STI dropped 3.5% on Oct. 8 alone, sliding to 5,412.96 from 5,608.44 the previous session, according to Capital Times calculations from Yahoo Finance data, and never recovered that ground.

Technology stocks fared worst. The FTSE ST All-Share Technology Index plunged 17.3% in October, according to the SGX. Chip-equipment and precision-engineering suppliers AEM, UMS Integration and Frencken each fell between 23% and 26% and saw institutional net outflows, although all three still carry large gains for the first 10 months of the year. The exchange tied part of the slide to Wall Street, where Alphabet shares fell 12.6% on Oct. 29.

Real estate investment trusts held up better. The iEdge S-Reit Index slipped 1.4%, and CapitaLand Integrated Commercial Trust drew the largest institutional net inflow of any Singapore-listed stock, at S$79.2 million, while returning 2% for the month. The SGX linked the Reits' resilience to a decline in long-term bond yields late in the month: the U.S. 10-year Treasury yield ended October at 4.9%, down from about 5.36% on Oct. 7.

The selloff came even as Singapore's economy grew 5.4% from a year earlier in the third quarter, according to advance estimates cited by the exchange.

Thailand and Malaysia: foreign funds pull back

In Bangkok, the SET Index closed October at 1,518.59, down 2.6% from 1,559.01 at the end of September, according to Capital Times calculations based on the exchange's September market report and Kaohoon International's closing data. The index lost 1.68% on Oct. 30 alone, its last session of the month, as electronics component makers led by Delta Electronics (Thailand) fell with global tech shares, Kaohoon reported.

Foreign investors were net sellers of 6.6 billion baht of Thai shares in October, according to Stock Exchange of Thailand investor-type data published by Kaohoon. That followed net foreign selling of 26.33 billion baht in September. Local institutions and individual investors were the buyers, each taking in about 5 billion baht net during the month. Overseas funds remain net buyers of roughly 18.5 billion baht for 2026, down from 24.86 billion baht at the end of September.

Malaysia's FBM KLCI ended October at 1,615.60, down 2.2% from 1,651.17 a month earlier, according to Capital Times calculations from Yahoo Finance data. Rakuten Trade said on Tuesday that foreign buying appeared to be returning only sporadically, according to The Star. Rakuten Trade's vice-president of equity research, Thong Pak Leng, told Bernama that any recovery could be gradual given uncertainty over U.S. interest rates and foreign fund flows.

Philippines near one-year low, Vietnam slips

The PSEi closed the month on Oct. 30 at 5,680.35, near its lowest level since Nov. 14, 2025, Michael Ricafort, chief economist at Rizal Commercial Banking Corp., told The Manila Times. He said the index ended October marginally higher after two straight months of losses. Ricafort argued that faster government catch-up spending and stronger governance reforms are needed to restore foreign investor confidence. He also pointed to oil prices near six-month highs and the risk of further U.S. rate increases as weights on the market.

Vietnam also lost ground. As Capital Times reported, the VN-Index ended October 1.5% lower as overseas investors kept selling.

November opened with mixed signals. Malaysia's index rose 0.24% to 1,619.51 on Monday on bargain hunting, while Thai brokers Maybank Securities (Thailand) and Daol Securities told Kaohoon they expected tech-related weakness and pre-election caution in the U.S. to weigh on the SET early in the week. The next local test comes Thursday, Nov. 5, when Bank Negara Malaysia announces its monetary policy decision.