South Korea is poised to move ahead of global peers into near-round-the-clock trading of US stocks, as brokerages in most other markets remain cautious.

South Korean brokerages will begin offering virtually round-the-clock trading in US stocks from Dec. 6, combining Nasdaq's newly expanded 23-hour trading schedule with an additional hour covered by the alternative trading platform Blue Ocean.

According to financial industry sources, Korean brokerages and the Korea Securities Depository (KSD) are completing preparations for the expanded system. The KSD said it would support brokerages by asking its local custodian, Citibank, to strengthen monitoring and ensure smooth settlement, while expecting minimal impact on staffing and operating costs.

US exchanges extend hours

The overhaul follows the US Securities and Exchange Commission's approval in April of Nasdaq's plan to extend trading to 23 hours a day, five days a week. The expanded session is scheduled to open at 9 p.m. Eastern Time on Sunday, Dec. 6 — ahead of the next trading day — corresponding to 11 a.m. Korea Standard Time on Monday, Dec. 7. That opening lands in late Monday morning in Seoul, meaning the official exchange session now begins inside Korean daytime hours — a window previously served mainly by alternative trading platforms.

The shift will include ETFs: NYSE Arca, an electronic exchange operated by NYSE Group and a major venue for ETF listings, is also set to extend its trading hours to 23 hours a day from Dec. 6.

Broad adoption in Korea, caution elsewhere

Korea stands out for the breadth of its adoption, with all domestic brokerages set to support the expanded schedule from day one. By combining Nasdaq's 23-hour window with existing alternative trading systems, including Blue Ocean, to cover the remaining hour, Korean brokerages will offer retail investors virtually uninterrupted access to US stocks.

Brokerages in other markets are taking a more cautious approach. In Japan and Taiwan, adoption is expected to be limited to a few major or foreign-focused firms, while activity in China remains largely institutional. In Europe, Australia and New Zealand, global and fintech platforms are leading adoption, as traditional retail firms cite liquidity and operational concerns. Across Southeast Asia, local brokerages have largely shelved their plans, leaving access mainly to high-net-worth clients through global trading desks.

For Korean firms, offering 24-hour trading is a natural step given local investors' strong demand for US stocks. According to KSD data, Korean investors' net purchases of US stocks reached $2.20 billion over the four trading days from Nov. 2 to 6. That exceeded August's $1.96 billion, more than doubled September's $1 billion, and amounted to about 40 percent of October's $5.42 billion.

Beyond extended hours

Industry officials say the significance of the overhaul goes beyond extending trading hours: it brings daytime trading, which previously relied on third-party alternative trading systems, into Nasdaq's official trading session.

"Daytime trading, which has so far been conducted through three alternative trading platforms — Blue Ocean, Bruce and Moon — will expand to include the New York Stock Exchange and Nasdaq," a brokerage official said. "Depending on their individual agreements, brokerages will receive real-time market data from the NYSE or Nasdaq, further strengthening their daytime trading infrastructure."

A rival for the Kospi

The expansion of US trading hours is also expected to put Nasdaq in more direct competition with Korea's Kospi, according to brokerage analysts.

"Nasdaq's move to 23-hour trading will challenge the assumption that the domestic stock market is the only market open during Korean daytime hours," said Park Woo-yeol, senior researcher at Shinhan Securities. "With cryptocurrency exchanges already operating around the clock, Nasdaq's regular session will become a direct competitor to the Kospi."

As competition among global markets intensifies, the Korea Exchange is also planning to gradually extend its own trading hours toward round-the-clock operation. At Korea Premium Week in September, the exchange announced a phased plan to introduce 24-hour trading.

"We plan to build the IT infrastructure for a single trading board by the end of 2027. We will first work to establish a 12-hour trading system by opening a premarket session ahead of regular trading hours," said Jin Dong-hwa, deputy head of the Kospi Market Division at the KRX.

The near-term dates to watch are concrete: Nasdaq's expanded session and NYSE Arca's extended hours both go live on Dec. 6, while the KRX's phased roadmap targets a premarket-based 12-hour system first and a single trading board by the end of 2027.

This article is based on reporting by Korea Herald Business.