KRX After-Hours Trading: Korea's Sessions

KRX after-hours trading runs in two separate windows, and neither one behaves like a US extended-hours session. The Korea Exchange ends its regular session at 3:30 p.m. Korea Standard Time, holds a short window where orders execute at that day's official closing price, then runs a continuous after-market until 8:00 p.m. KST. The clock times are the easy part. What decides the price an order can get is which price-formation mechanism is running when the order arrives.

What are the KRX trading hours?

Korea trades Monday to Friday, with no lunch break in the regular session. Read KRX's published guide to trading in the Korean stock market in order and the equity day is a chain of mechanisms rather than one long session. All times below are KST.

• Pre-market closing-price session, 8:30 a.m. to 8:40 a.m. Orders match at the previous session's closing price.
• Opening call auction. Orders are received ahead of the open and batched into a single opening price printed at 9:00 a.m.
• Regular session, 9:00 a.m. to 3:20 p.m. Continuous matching on price priority, then time priority.
• Closing call auction, 3:20 p.m. to 3:30 p.m. One batch of orders sets the official closing price.
• After-hours closing-price session. Orders are received from 3:30 p.m. and execute between 3:40 p.m. and 4:00 p.m. at the closing price the auction just set.
• After-market, 4:00 p.m. to 8:00 p.m. Continuous matching, live since 14 September 2026.

A daily price band of plus or minus 30% around the previous close applies across the whole day, and equity settlement is T+2.

How does KRX after-hours trading work?

Start with the two closing-price windows, which have no US equivalent. In the 8:30 a.m. window, and again from 3:40 p.m., there is no price discovery at all. The price is an input: the previous session's close in the morning, that day's close in the afternoon. Buyers and sellers queue at that one price and match on time priority while quantity lasts. An order there asks for shares at a price already known, and the exchange's order-type table admits only limit orders in both windows. A market order is not a valid instruction when the price is already fixed.

The evening window changed shape this month. Through 12 September 2026 it was a periodic call auction: orders collected for ten minutes, one single price cleared the batch, and the cycle repeated until 6:00 p.m. KRX retired that mechanism and opened the after-market on 14 September 2026, running 4:00 p.m. to 8:00 p.m. on the same continuous price and time priority the regular session uses. Three order types are accepted, limit, best limit, and most favorable limit, while market orders and conditional limit orders are not. The plus or minus 30% band still applies, and the volatility interruption carries over from the day session: a large enough move suspends continuous matching and gathers orders into a two-minute call auction before matching resumes. ETFs and ETNs are excluded at launch, and an issue that did not trade in the regular session cannot trade in the evening. Korea's alternative venue, Nextrade, runs to 8:00 p.m. as well, and a Korean broker routes between the two under a best-execution standard.

Which price does an order get in each window?

Read the Korean day as prices rather than as clock times and it compresses to five rules.

• Pre-market closing-price window: the previous session's close, fixed. Limit orders only.
• Opening and closing auctions: one clearing price for the entire batch. Market orders are accepted here, and a market order in an auction takes whatever price the batch clears at.
• Regular session: a market order crosses the spread and takes resting liquidity from the top of the book down, as deep as it needs to go.
• After-hours closing-price window: the day's official close, fixed. Limit orders only.
• After-market: continuous matching with limit orders only, inside the same daily band.

The pattern holds across the session chain. Where KRX wants an orderly, verifiable print, it either fixes the price outright or batches orders into a single auction price. Where it wants continuous trading outside the main session, it takes the market order away.

How is this different from US after-hours trading?

The US model, laid out in our guide to after-hours and premarket trading, answers the same question with one mechanism instead of several. Extended-hours trading in the US runs 4:00 a.m. to 9:30 a.m. and 4:00 p.m. to 8:00 p.m. Eastern, continuous the whole way, with no fixed-price window anywhere in it. Most US brokers accept limit orders only outside regular hours, which is the one rule the two markets share. What differs is the other side of the trade: a thin, fragmented book instead of a queue at a known price. Regular US stock market hours cover the rest of that clock.

Thin is measurable. The panel below splits about a month of one-minute bars into half-hour blocks of New York clock time and shows what share of each name's total volume printed in each block.

SELECT
    et_time,
    round(100 * sumIf(shares, ticker = 'AAPL') / sum(sumIf(shares, ticker = 'AAPL')) OVER (), 3) AS aapl_share_pct,
    round(100 * sumIf(shares, ticker = 'KO')   / sum(sumIf(shares, ticker = 'KO'))   OVER (), 3) AS ko_share_pct
FROM
(
    SELECT
        ticker,
        formatDateTime(toStartOfInterval(toTimeZone(window_start, 'America/New_York'), INTERVAL 30 MINUTE), '%H:%i') AS et_time,
        toFloat64(volume)                                                                                           AS shares
    FROM global_markets.delayed_stocks_minute_aggs
    WHERE ticker IN ('AAPL', 'KO')
      AND window_start >= today() - 45
      AND window_start <  today() - 2
      AND toHour(toTimeZone(window_start, 'America/New_York')) >= 4
      AND toHour(toTimeZone(window_start, 'America/New_York')) < 20
    UNION ALL
    SELECT
        ticker,
        '16:00'                                    AS et_time,
        toFloat64(maxIf(size, has(conditions, 8))) AS shares
    FROM global_markets.stocks_trades
    WHERE ticker IN ('AAPL', 'KO')
      AND sip_timestamp >= today() - 45
      AND sip_timestamp <  today() - 2
      AND toHour(toTimeZone(sip_timestamp, 'America/New_York')) = 16
      AND toMinute(toTimeZone(sip_timestamp, 'America/New_York')) < 10
    GROUP BY ticker, toDate(toTimeZone(sip_timestamp, 'America/New_York'))
    HAVING countIf(has(conditions, 8)) > 0
)
GROUP BY et_time
ORDER BY et_time

Volume hugs the floor through the premarket blocks, steps up at the 9:30 a.m. open, and falls away again once the block that opens at 4:00 p.m. ET has passed. That block holds the closing auction print: 21.692% of AAPL's month and 22.879% of KO's. The half hour from 09:30 ET carries 13.968% of AAPL's volume for the month. The half hour from 16:30 carries 0.767% for AAPL and 0.116% for KO, a fraction of a percent of the day in each case.

A thin book shows up in the spread as well as in the volume. The quoted spread is the gap between the best bid and the best offer, and it is what a marketable order pays to cross. The next panel measures it on one pinned session, Tuesday 15 September 2026, in basis points of the midpoint. One basis point is a hundredth of a percent.

SELECT
    formatDateTime(toStartOfInterval(toTimeZone(sip_timestamp, 'America/New_York'), INTERVAL 30 MINUTE), '%H:%i') AS et_time,
    round(quantileDeterministic(0.5)(20000 * toFloat64(ask_price - bid_price) / toFloat64(ask_price + bid_price), toUInt64(sequence_number)), 2) AS median_spread_bps,
    round(quantileDeterministic(0.9)(20000 * toFloat64(ask_price - bid_price) / toFloat64(ask_price + bid_price), toUInt64(sequence_number)), 2) AS p90_spread_bps
FROM global_markets.cache_stocks_quotes
WHERE ticker = 'AAPL'
  AND sip_timestamp >= toDateTime('2026-09-15 08:00:00', 'America/New_York')
  AND sip_timestamp <  toDateTime('2026-09-15 20:00:00', 'America/New_York')
  AND bid_price > 0
  AND ask_price > bid_price
GROUP BY et_time
ORDER BY et_time

In the half hour from 09:30 ET, the median quoted spread measured 1.51 bps. In the evening block from 18:00, the median measured 4.22 bps and the 90th percentile 8.74 bps. Same stock, same day, a different book underneath it. In Korea's 3:40 p.m. window that question never comes up, since the price is fixed before the window opens and the only uncertainty left is whether an order fills at all.

Both markets treat the close as an auction

The KRX closing-price session borrows its price from the 3:20 p.m. auction. US markets run the same kind of event at the end of the day, a closing cross that prints one official price for the session, and the panel below walks the final minutes into it one bar at a time.

SELECT
    et_time,
    round(100 * sum(shares) / any(d.session_volume), 3) AS share_of_session_pct
FROM
(
    SELECT
        if(has(conditions, 8), '16:00',
           formatDateTime(toTimeZone(sip_timestamp, 'America/New_York'), '%H:%i')) AS et_time,
        toFloat64(size)                                                          AS shares
    FROM global_markets.stocks_trades
    WHERE ticker = 'AAPL'
      AND sip_timestamp >= toDateTime('2026-09-15 15:50:00', 'America/New_York')
      AND sip_timestamp <  toDateTime('2026-09-15 16:10:00', 'America/New_York')
      AND NOT hasAny(conditions, [15, 16, 38])
      AND (has(conditions, 8)
           OR sip_timestamp < toDateTime('2026-09-15 16:00:00', 'America/New_York'))
) AS m
CROSS JOIN
(
    SELECT toFloat64(sum(size)) AS session_volume
    FROM global_markets.stocks_trades
    WHERE ticker = 'AAPL'
      AND sip_timestamp >= toDateTime('2026-09-15 04:00:00', 'America/New_York')
      AND sip_timestamp <  toDateTime('2026-09-15 20:00:00', 'America/New_York')
      AND NOT hasAny(conditions, [15, 16, 38])
) AS d
GROUP BY et_time
ORDER BY et_time

On that pinned session, the closing cross, the final bar labelled 16:00 ET, carried 20.333% of everything AAPL traded between 4:00 a.m. and 8:00 p.m. in a single trade, against 0.573% in the minute from 15:50. That bar is the auction print alone, read from the tape by its closing-print condition code. The vendor's one-minute bars leave the print out entirely, so a 16:00 minute bar holds only the scattered trades around it. A single auction price, whatever share of the tape it ends up carrying, is exactly what Korea's after-hours closing-price window then hands to every order sitting in its queue.

Converting KST to ET, and the daylight saving gap

Korea does not observe daylight saving time. KST is UTC+9 all year. New York moves twice a year, and the offset between the two moves with it: Seoul runs 13 hours ahead of New York from the second Sunday in March to the first Sunday in November, and 14 hours ahead the rest of the year.

• Regular session, 9:00 a.m. to 3:30 p.m. KST, is 8:00 p.m. to 2:30 a.m. ET under US daylight time, and 7:00 p.m. to 1:30 a.m. ET under US standard time.
• After-market, 4:00 p.m. to 8:00 p.m. KST, is 3:00 a.m. to 7:00 a.m. ET under US daylight time, and 2:00 a.m. to 6:00 a.m. ET under US standard time.

A Korean Tuesday session opens on Monday evening in New York. Toronto keeps New York's clock year round, as TSX trading hours and holidays show, and Frankfurt shifts on European dates that miss the US ones by a couple of weeks, which Xetra trading hours and holidays cover. Korea is the clean case: it never shifts, and the entire adjustment lands on the New York side. For a Korean issuer meeting the US clock from the other direction, see the SK hynix Nasdaq debut.

FAQ

What time is KRX after-hours trading?

There are two windows. The closing-price session takes orders from 3:30 p.m. KST and executes from 3:40 p.m. to 4:00 p.m. at the day's official closing price. The after-market then runs continuously from 4:00 p.m. to 8:00 p.m. KST.

Can you place a market order in KRX after-hours trading?

No. Both after-hours windows take limit orders only. In the closing-price session the price is fixed at the day's close, and in the after-market KRX accepts limit, best limit, and most favorable limit orders while excluding market orders and conditional limit orders.

Does Korea change its clocks for daylight saving?

No. Korea Standard Time is UTC+9 year round. New York's switch is what moves the gap, from 13 hours during the US daylight period to 14 hours during the US standard period.

What happened to the KRX after-hours single-price auction?

It was retired. The 4:00 p.m. to 6:00 p.m. session that gathered orders into one price every ten minutes ended, and the continuous after-market running to 8:00 p.m. KST replaced it on 14 September 2026.

Is Korea's after-market the same as US after-hours trading?

Both are continuous and both restrict market orders, and the resemblance stops there. Korea keeps the regular session's 30% price band and its volatility interruption in the evening, while US extended hours run on venue rules, with no consolidated auction and a far thinner book.

Every panel here carries the exact SQL that produced it. To run the same clock-time breakdown on a name you follow, ask the question in plain English on the Strasmore terminal.