Taiwan's regulator is leaving it to brokers to decide whether to extend overseas trading hours, a change that would give local investors far more freedom to trade US stocks.

• Nasdaq starts 23-hour-a-day, five-day-a-week trading on December 6, pausing only one hour a day.
• Taiwan's financial regulator says brokers can extend their US-stock order windows if staffing and systems can handle it.
• Major local brokers are already planning longer hours, with pre-market seen as the bigger draw — orders could run from mid-afternoon to early morning.
• Demand is booming: Taiwanese trading in foreign stocks doubled from a year ago, and US shares make up about seven-tenths of it.
• Brokers must also renegotiate terms with their US partners before opening the extra sessions.

Outlook: Expect Taiwan's biggest brokers to announce extended US-stock trading windows before Nasdaq's December launch.