Order Modify Kor Queue Priority Go Loss?

Order modification and queue priority dey work against each other. For US equity books and most futures venues, if you change the price of a resting limit order, e go move to the back of the queue for the new price. If you increase the displayed size, na the same thing go happen. If you reduce the size, you go keep your position. If you cancel an order and send another fresh one, na new arrival with new timestamp, no matter wetin your platform button dey call am.

Order modify kor queue priority go loss?

Four rules cover almost every venue wey self-directed trader fit use.

• If you change the price, you lose priority. The order go enter for the new price like new order, behind everything wey don dey rest there.
• If you increase the displayed size, you lose priority. Some venues go put only the extra quantity back for queue, while dem leave the original slice where e dey. Others go reset the time for the whole order. For both cases, the extra shares no go keep the old position.
• If you reduce the displayed size, you keep priority. The venue sees am as partial cancel, and removing quantity no cost you your position for the line.
• If you cancel and send the order again, you lose priority every time. Plus, gap go dey between the two orders when nothing from you dey active.

The difference get clear reason. Time priority na the reward wey the order book give you for staying for one price while other people wait. When you add size or move the price, you dey take new risk, so the order starts from the back. When you remove size, you dey reduce risk, and venue no get reason to charge you for that.

For pro rata book, the calculation different because allocation follows the size you display, not the time you arrive. Price time priority versus pro rata explain both methods.

Modify in place or cancel and replace?

Venue dey treat these two instructions differently. Amendment, wey your platform fit call modify or replace, na one message wey identify the existing order and the change. E apply atomically: either the change enter, or the order remain as e be. Cancel followed by new order na two events with gap between dem. During that gap, you no get any place for the book. If market trade through your price inside the gap, you no dey there to catch am.

Some venues dey process amendment internally as cancel plus new order. Some brokers too dey turn amendment into cancel and replace before dem send am out, even when venue support true in-place change. Result na the same: you lose your priority. If venue reject amendment, original order still dey rest for book. But if cancel succeed before venue reject the new order, nothing remain working for you. Even amendment wey preserve priority usually return with new order identifier. So your own records fit show new order, even though the book still count am as the old one.

Amendment cost

Queue position get value only based on wetin the tape fit pay. Shares wey dey ahead of you must trade before your own go trade, and the rate dem dey trade fit swing widely during one session.

SELECT
    formatDateTime(toStartOfFifteenMinutes(et), '%H:%i')                    AS et_time,
    round(toFloat64(avg(volume)) / 1000, 1)                                 AS avg_k_shares_per_min,
    round(quantileDeterministic(0.5)(toFloat64(volume),
                                     toUInt64(toUnixTimestamp(et))) / 1000, 1) AS median_k_shares_per_min
FROM
(
    SELECT
        toTimeZone(window_start, 'America/New_York') AS et,
        volume
    FROM global_markets.delayed_stocks_minute_aggs
    WHERE ticker = 'AAPL'
      AND window_start >= '2026-06-01'
      AND window_start <  '2026-07-01'
      AND (toHour(toTimeZone(window_start, 'America/New_York')) * 60
           + toMinute(toTimeZone(window_start, 'America/New_York'))) >= 570
      AND (toHour(toTimeZone(window_start, 'America/New_York')) * 60
           + toMinute(toTimeZone(window_start, 'America/New_York'))) < 960
)
GROUP BY et_time
ORDER BY et_time

Throughout June 2026, the quarter hour wey start for 09:30 ET trade median of 182.8 thousand AAPL shares per minute, compared with 62 thousand for the bucket wey start for 12:00. Na the same order and the same price. But the wait ahead of am no be the same for market open and middle of the day.

Probability say order go fill before and after amendment

Amendments get price based on probability. The panel below count, across one month of regular-session minutes, how many times one minute of tape carry at least a particular number of shares. Read am as the chance say queue of that size wey dey in front of you go clear inside one minute.

WITH minute_volume AS
(
    SELECT
        ticker,
        toStartOfMinute(toTimeZone(window_start, 'America/New_York')) AS et_minute,
        sum(volume)                                                   AS shares
    FROM global_markets.delayed_stocks_minute_aggs
    WHERE ticker IN ('AAPL', 'KO')
      AND window_start >= '2026-06-01'
      AND window_start <  '2026-07-01'
      AND (toHour(toTimeZone(window_start, 'America/New_York')) * 60
           + toMinute(toTimeZone(window_start, 'America/New_York'))) >= 570
      AND (toHour(toTimeZone(window_start, 'America/New_York')) * 60
           + toMinute(toTimeZone(window_start, 'America/New_York'))) < 960
    GROUP BY ticker, et_minute
)
SELECT
    q.ahead                                                                                           AS shares_ahead,
    round(100 * countIf(mv.ticker = 'AAPL' AND mv.shares >= q.ahead) / countIf(mv.ticker = 'AAPL'), 1) AS aapl_pct_of_minutes,
    round(100 * countIf(mv.ticker = 'KO'   AND mv.shares >= q.ahead) / countIf(mv.ticker = 'KO'),   1) AS ko_pct_of_minutes
FROM minute_volume AS mv
CROSS JOIN
(
    SELECT arrayJoin([500, 1000, 2000, 4000, 8000, 16000, 32000, 64000, 128000]) AS ahead
) AS q
GROUP BY q.ahead
ORDER BY q.ahead

With 500 shares ahead, 100 percent of AAPL minutes carry enough volume, compared with 100 percent of KO minutes. At 8000 shares, the AAPL figure na 100 percent. For 128000 shares, e drop to 22.2 percent. The curve only dey slope one way. Losing priority simply mean say you move right along the curve.

Treat the line as optimistic ceiling. Volume for one minute dey print across many prices and both sides of the market. Only small part of am land for your price level, so one real queue go clear more slowly than this. Minutes wey no get any prints no dey count. Estimating your queue position go make the picture tighter with depth and cancel rates.

The break even re-price distance

Make we now put price on the amendment. Assume say buy order dey wait, with 8,000 shares ahead of am and 60 percent chance say e go clear within the next minute. If you improve the bid by one cent, order go move to new best price with nobody in front. Call the odds there 99 percent. That improvement cost one cent per share for every fill.

Use V for wetin one fill worth per share, including your edge plus any rebate. Use t for the re-price distance. Amendment break even when improved odds multiplied by the lower payoff equal old odds multiplied by the full payoff. After rearranging, e become one line:

t = V x (1 - p0 / p1)

If one fill worth 3 cents per share and odds move from 60 to 99 percent, break even distance dey around 1.2 cents. One-cent improvement pay for itself. Two-cent chase no pay.

Run the same line for bot wey only edge na maker rebate. Top-tier maker rebates for big US equity exchanges dey around 0.20 to 0.30 cents per share for published fee schedules as of mid 2026. So make we call am quarter of one cent. Formula put break even distance around 0.1 cents, while the smallest price change any US venue accept na full cent, about ten times too far. Bot wey re-price to protect rebate dey pay one tick to chase quarter of one.

Dem pay rebate on fills, never on intention. Order wey hold fine queue position but never trade earn nothing. Rebate wey you never collect no be saving. Maker taker fees and rebates explain how those schedules pay.

Wey no room to improve

Price improve fit only happen when bid and offer get space between dem. For the biggest names, most times, dem no get that space.

SELECT
    ticker                                                                                  AS symbol,
    round(avg(toFloat64(ask_price) - toFloat64(bid_price)) * 100, 2)                        AS avg_spread_cents,
    round(100 * countIf(toFloat64(ask_price) - toFloat64(bid_price) <= 0.0105) / count(), 1) AS one_tick_wide_pct
FROM global_markets.cache_stocks_quotes
WHERE ticker IN ('AAPL', 'KO', 'SPY', 'NVDA', 'COST', 'NFLX')
  AND sip_timestamp >= '2026-06-10 13:30:00'
  AND sip_timestamp <  '2026-06-10 20:00:00'
  AND bid_price > 0
  AND ask_price > bid_price
  AND toFloat64(ask_price) - toFloat64(bid_price) < 5
GROUP BY ticker
ORDER BY one_tick_wide_pct DESC

NFLX quote updates show one cent spread for 81.4 percent of the time on 10 June 2026, with average spread of 1.3 cents. For the other side of the panel, COST average 77.53 cents. For one-tick market, no price dey between bid and offer wey you fit move to. The only way to move ahead for queue na to cross the spread. That one make you the taker: you pay taker fee instead of collecting rebate, and you give up the full spread, no be just one tick.

Re-pricing bot dey face this choice how often

A follow-the-market bot no dey make this trade just once. E dey make am every time top of book move away from e order.

SELECT
    formatDateTime(toStartOfFifteenMinutes(et), '%H:%i') AS et_time,
    uniqExactIf(bid_price, ticker = 'AAPL')              AS aapl_distinct_bids,
    uniqExactIf(bid_price, ticker = 'KO')                AS ko_distinct_bids
FROM
(
    SELECT
        toTimeZone(sip_timestamp, 'America/New_York') AS et,
        ticker,
        bid_price
    FROM global_markets.cache_stocks_quotes
    WHERE ticker IN ('AAPL', 'KO')
      AND sip_timestamp >= '2026-06-10 13:30:00'
      AND sip_timestamp <  '2026-06-10 20:00:00'
      AND bid_price > 0
)
GROUP BY et_time
ORDER BY et_time

AAPL best bid visit 359 different prices inside the quarter hour wey start for 09:30 ET on 10 June 2026, and 152 inside the quarter hour wey start for 15:45. KO best bid visit 78 prices inside that opening bucket. Every one of those moves na amendment wey re-pricing bot fit send, and every amendment start the waiting time again. Grid trading bots choose the other side of the decision by parking ladder for fixed prices: the prices go stale, but the priority remain.

Icebergs and self trade prevention

Two second-order effects dey catch people off guard.

Reserve orders, wey people usually call iceberg orders, dey show one small part and keep the rest hidden. For most books, each time dem refresh the displayed part, e join the back of the queue for that price. So, one large iceberg dey behave like many small orders wey keep giving up their position to size wey dey fully displayed. If you amend the display size, the same cycle go start again.

Self trade prevention na the other one. Venues no go allow one participant order execute against another order from the same participant wey dey rest for the book. The usual remedy na to cancel one of the two orders, or for some venues, cancel both. Bot wey dey re-price across a narrow book fit knock out its own quote for the other side. That one fit turn one amendment into two lost positions for the queue. Amendments normally keep the original time in force, but cancel and replace resets am. Order time in force cover this detail.

FAQ

If person change the price of a limit order, e lose im place for queue?

Yes. For US equity books and most futures venues, dem go treat the order as new for the new price. E go enter behind every share wey don dey rest there. The only change wey keep priority na to reduce the size for the same price.

Cancel and replace na the same thing as modifying an order?

Dem no be the same for every venue. Amendment na one message, and e fit keep priority when na only the size wey reduce. Cancel and replace na two events. Gap dey there wey none of your order dey rest. The replacement always go join back of the queue.

If person reduce the size of an order, e go keep queue priority?

Yes, if na the same price. Venues dey treat size reduction as partial cancellation, and the remaining shares keep their original timestamp. Increasing the size no dey work the same way.

Wetin queue position really worth?

Na the fill probability wey e give you, multiply by wetin one fill worth to you. You fit measure both sides. The panels above show how much volume dey print per minute. Your own edge plus any rebate set the value of a fill.

Every panel here get the SQL wey produce am. Change the ticker or the date range, then ask the same question for any name on the Strasmore terminal.