%TRAILING

Syntax

SET STOP %TRAILING x

Parameters

How it works

%TRAILING combines with SET STOP only. Unlike the static SET STOP %LOSS, the trailing variant ratchets. For a long position the stop starts x percent below the position price and rises whenever price makes a new high since entry, always keeping the x percent gap to that high. It never moves down. For a short position the logic mirrors: the stop trails x percent above the lowest price reached.

Once the instruction executes, the setting persists and applies to the current position and to all future positions until another SET STOP call replaces it. A value of 0 disables the trailing stop.

Because the distance is a percentage, the absolute gap widens as price rises and narrows as it falls, which keeps the protection proportional on instruments with large price ranges. When the trailed level is hit, the position closes at market like an ordinary stop.

Examples

Example 1, Trend entry protected by a 1.5 percent trail (ProBacktest)

// Long-term and short-term moving averages
i1 = Average[100](close)
i2 = Average[5](close)

// Enter on a pullback inside an uptrend, after three rising lows
tradeinitiate = Close > i1 AND Close < i2 AND Low[3] > Low[2] AND Low[2] > Low[1] AND Low[1] > Low
tradeclose = Close > Close[1]

IF NOT LongOnMarket AND tradeinitiate THEN
    BUY 1 CONTRACTS AT MARKET
ENDIF

IF LongOnMarket AND tradeclose THEN
    SELL AT MARKET
ENDIF

// Trail the stop 1.5 percent below the highest price since entry
SET STOP %TRAILING 1.5

The strategy buys pullbacks in an uptrend and exits on strength. If the exit signal never fires, the trailing stop closes the position after a 1.5 percent retreat from the best price reached.

Example 2, Percent trail on a short breakdown (ProOrder)

support = Lowest[20](low)
IF NOT ShortOnMarket AND close crosses under support[1] THEN
    SELLSHORT 1 CONTRACT AT MARKET
ENDIF
// The stop trails 2 percent above the lowest price since entry
SET STOP %TRAILING 2

On the short side the stop follows price downward and only a 2 percent bounce from the low closes the trade.

Example 3, Fixed stop first, trail after the trade is in profit (ProOrder)

DEFPARAM CumulateOrders = false

IF NOT OnMarket AND RSI[14](close) < 30 THEN
    BUY 1 CONTRACT AT MARKET
    // Static protection while the trade develops
    SET STOP %LOSS 1
ENDIF

// Switch to a tighter trailing stop once price is 1 percent ahead
IF LongOnMarket AND close >= TRADEPRICE * 1.01 THEN
    SET STOP %TRAILING 0.5
ENDIF

A common two-phase pattern: a static percent stop caps the initial risk, then a tighter %TRAILING takes over once the position shows a profit. The switch is one-way for the rest of the trade because the condition stays true once reached, and each execution keeps the same value.

Common errors and gotchas

• Wrong SET pairing. %TRAILING is a stop instruction, so it combines with SET STOP only. SET TARGET %TRAILING is not a valid form; targets use %PROFIT.
• One stop slot. %TRAILING, %LOSS, $TRAILING, PLOSS and BREAKEVEN all write to the same internal stop. The most recent SET STOP call wins, so mixing a static stop and a trailing stop in per-bar logic replaces one with the other rather than combining them.
• Bar-based trailing in backtests. ProBacktest updates the trailed level from bar data, so intrabar spikes may be handled optimistically compared with live tick-by-tick execution. Expect small differences between backtest and live fills.
• Too tight a percentage. A trail below the instrument's typical bar range gets tagged almost immediately. Compare x against average volatility, for example a percentage derived from AverageTrueRange, before fixing the value.

Related instructions

• $TRAILING, trailing stop as a fixed money amount.
• PTRAILING, trailing stop as a distance in points.
• TRAILING, the trailing stop family overview.
• %LOSS, static stop loss as a percentage of the position price.
• %PROFIT, take profit as a percentage of the position price.
• BREAKEVEN, moves the stop or target to the entry price.
• STOP, pending stop orders and the SET STOP family.
• TRADEPRICE, entry price of a given trade.
• LONGONMARKET, true while a long position is open.