For anyone trading Korean equities, this is a genuine expansion of the trading day rather than a cosmetic change, since real time continuous matching replaces a system that only cleared orders every 10 minutes. That should meaningfully improve price discovery after the regular 3:30pm close, letting traders react immediately to earnings, corporate actions or global headlines that land during the new window rather than waiting for the next 10 minute batch or the following day's open. The exclusion of ETFs and ETNs from the initial rollout is worth flagging for anyone using those instruments to hedge or gain sector exposure, since that liquidity will remain confined to the regular session for now. The competitive backdrop also matters: Nextrade has already captured meaningful market share partly on the strength of its longer hours, so liquidity in the new KRX after hours window may take time to build as order flow redistributes between the two venues.---Korean stock traders are about to get four extra hours of real time trading a day, as the exchange fights to keep pace with a fast growing rival.Summary:The Korea Exchange will launch a new real time after hours trading session running from 4pm to 8pm KST starting September 14, following approval from the Financial Services CommissionThis replaces the previous system, which matched after hours orders in a single price auction every 10 minutes between 4pm and 6pmThe regular trading session remains unchanged, running to 3:30pm, followed by a closing price session from 3:40pm to 4pm before the new after hours window beginsEligible securities include the large majority of Kospi and Kosdaq listed stocks and depositary receipts, though ETFs and ETNs are excluded from the initial rollout due to volatility concerns, and administrative issue, investment warning, investment danger and ultra low liquidity stocks are also excludedOrders in the after hours session are limited to limit orders only, with the same 30% price band and volatility interruption rules that apply during the regular sessionKRX has framed the move as a response to competition from Nextrade, the alternative trading platform that launched in March and has already captured over 30% market share partly through longer hours and lower fees, as well as to the trend of extended trading hours at major exchanges including the NYSE and NasdaqThe Korea Exchange will launch a new real time after hours trading session for Kospi and Kosdaq listed stocks from September 14, extending the country's effective trading day and stepping up competition with the fast growing alternative platform Nextrade. The move follows approval from the Financial Services Commission for revisions to the operating rules governing both markets.Under the new system, the regular session will continue to run until 3:30pm, followed by a closing price session between 3:40pm and 4pm. The after hours market will then operate continuously from 4pm to 8pm, with buy and sell orders matched in real time as they cross, rather than in scheduled batches. This replaces the previous after hours arrangement, which matched orders only every 10 minutes using a single price auction mechanism between 4pm and 6pm, a system traders had criticised as slow to reflect fresh information reaching the market after the close.For traders, the practical scope of the change matters as much as the headline hours. The after hours session will cover the large majority of Kospi and Kosdaq listed shares and depositary receipts, but ETFs and ETNs are excluded for now, with the exchange citing concerns about market volatility. Stocks under administrative issue status, investment warning or investment danger designations, and ultra low liquidity names are also excluded. Orders during the after hours window are restricted to limit orders only, and the same 30% daily price band and volatility interruption safeguards used in the regular session will continue to apply.KRX has been explicit that competitive pressure is a driving factor behind the change. Nextrade, an alternative trading platform that launched in March, has already captured more than 30% market share, helped in part by its own longer trading hours and lower commission structure. The exchange also pointed to the broader global trend of extended trading hours, noting that major US markets including the New York Stock Exchange and Nasdaq have been pushing in the same direction. KRX said it ran a 23 week simulation of the new system between April and early September to test stability before going live, and indicated it intends to review further extensions, including a previously discussed early morning pre-market session, based on how the after hours launch performs.For traders active in Korean equities, the immediate takeaway is straightforward: from September 14, the effective daily window for reacting to news and repositioning in most Kospi and Kosdaq names extends by roughly four hours, though liquidity in that new window is likely to build gradually as order flow settles between the Korea Exchange and Nextrade. This article was written by Eamonn Sheridan at investinglive.com.