Computer network glitches occurred sequentially at major domestic brokerage firms this morning (September 14) in connection with the pre-market session (8:00 AM to 8:50 AM) operated by the alternative trading system Nextrade (NXT).

At Mirae Asset Securities, some delays occurred in checking the execution of buy and sell orders on the Nextrade pre-market through its Home Trading System (HTS) and Mobile Trading System (MTS).

Although the user-facing issues were resolved by the end of the pre-market session, allowing normal trading from the opening of the regular market, the operation of the Smart Order Routing (SOR) system—which distributes orders between the Korea Exchange (KRX) and the alternative trading system Nextrade (NXT)—remains restricted.

Mirae Asset Securities announced through a notice, "Due to SOR system maintenance, orders placed via the SOR system will be transmitted to the KRX for the regular market, and to NXT (3:30 PM to 4:00 PM) or KRX (4:00 PM to 8:00 PM) for the after-market."

A source familiar with the matter said, "The cause is reportedly related to a problem with the Smart Order Routing (SOR) system provided by the alternative trading system Nextrade (NXT)."

Samsung Securities users also experienced trading-related issues during the pre-market session today.

In a notice titled "Emergency Cancellation Notice Due to SOR Failure," Samsung Securities stated, "Due to an SOR failure, cancellation orders were not processed properly, so we switched processing to the KRX market. Please request cancellation for any previously uncancelled orders."

An industry insider noted, "With the opening of the KRX after-market, the application time for SOR for best execution has been extended from 3:30 PM to 8:00 PM, prompting brokerages to expand and modify their SOR-related systems." The insider added that confusion may have occurred during the initial application of these changes today.

Meanwhile, starting today, the KRX is opening an "after-market" where stocks can be traded in real time from 4:00 PM to 8:00 PM.

This replaces the existing after-hours single-price trading with real-time trading.

While this is expected to significantly expand tradable stocks and broaden investment choices for investors, the actual changes may not feel substantial to general investors since NXT is already operating an after-market until 8:00 PM.

(Photo: Yonhap News)