Stop Loss and Stop Gain Rules

ta4j now provides a full stop-rule toolkit that covers fixed %, fixed amount, trailing variants, and volatility/ATR-adaptive variants for both loss and gain exits.

Use this page as the operational guide for:

• Choosing the right stop type for your strategy style.
• Wiring stop rules into strategy exits.
• Applying stop logic safely in live trading.

Rule families

Fixed percentage (classic)

• StopLossRule
• StopGainRule
• TrailingStopLossRule
• TrailingStopGainRule

These use percentage distance from entry (or favorable move for trailing variants).

Percent inputs are percentage points (for example, 3 means 3%, not 0.03).

Best when:

• You want simple, interpretable risk limits.
• Price scale does not change dramatically over time.

Fixed amount (flat-dollar / flat-price-distance)

• FixedAmountStopLossRule
• FixedAmountStopGainRule
• TrailingFixedAmountStopLossRule
• TrailingFixedAmountStopGainRule

These use an absolute price distance (for example: $10 from reference).

Best when:

• Instruments trade in a stable price range.
• You size positions independently and want fixed distance exits.

Volatility-driven

• VolatilityStopLossRule
• VolatilityStopGainRule
• VolatilityTrailingStopLossRule
• VolatilityTrailingStopGainRule
• AverageTrueRangeStopLossRule
• AverageTrueRangeStopGainRule
• AverageTrueRangeTrailingStopLossRule
• AverageTrueRangeTrailingStopGainRule

These use a dynamic threshold based on volatility indicators (typically ATR multiplied by a coefficient).

From 0.22.3, ATR-based rules support constructors that accept a custom ATRIndicator directly (including trailing variants), so you can share precomputed ATR pipelines instead of rebuilding ATR inside each rule.

Best when:

• Volatility regimes shift frequently.
• You want stops that widen in high vol and tighten in low vol.

Quick selection guide

• Trend-following swing systems:
  • Start with AverageTrueRangeTrailingStopLossRule for downside protection.
  • Pair with TrailingStopGainRule or AverageTrueRangeTrailingStopGainRule for profit capture.
• Mean-reversion systems:
  • Use tighter StopLossRule / FixedAmountStopLossRule.
  • Use non-trailing StopGainRule / FixedAmountStopGainRule at expected reversion targets.
• Intraday scalping:
  • Prefer fixed amount stops when spread/tick structure dominates.
  • Add a volatility stop fallback for regime changes.

How to wire exits

ClosePriceIndicator close = new ClosePriceIndicator(series);
ATRIndicator atr = new ATRIndicator(series, 14);

Rule riskExit = new AverageTrueRangeTrailingStopLossRule(close, atr, 2.0)
        .or(new AverageTrueRangeTrailingStopGainRule(close, atr, 3.0))
        .or(new StopLossRule(close, series.numFactory().numOf(1.5))); // hard fail-safe

Rule signalExit = new CrossedDownIndicatorRule(fast, slow);
Rule exitRule = signalExit.or(riskExit);

Strategy strategy = new BaseStrategy(entryRule, exitRule);

Notes:

• Keep one hard fail-safe stop even when using adaptive stops.
• Avoid stacking many correlated stop rules unless each has a distinct purpose.
• TrailingStopGainRule and AverageTrueRangeTrailingStopGainRule are two-stage: they activate only after reaching the initial gain threshold, then trigger on retracement from the favorable extreme.
• AverageTrueRangeTrailingStopGainRule requires a positive ATR coefficient; invalid values fail fast with IllegalArgumentException.

Using stop-price models for risk analytics

Several rules implement:

• StopLossPriceModel
• StopGainPriceModel

This lets you query stop prices directly (for example in risk budgeting or custom position sizing flows) without duplicating threshold math.

For fixed-percentage and fixed-distance calculations, you can also use helper methods from StopLossRule / StopGainRule directly:

Num stopLoss = StopLossRule.stopLossPrice(entryPrice, numOf(2), true);
Num stopGain = StopGainRule.stopGainPrice(entryPrice, numOf(4), true);
Num trailingGain = StopGainRule.trailingStopGainPrice(highestPrice, numOf(1.5), true);

If you evaluate strategy quality in risk units, pair your stop model with RMultipleCriterion (for example, new RMultipleCriterion(new StopLossPositionRiskModel(5))) so research and stop geometry stay aligned.

Live trading usage patterns

1) Match your reference price to execution reality

• If broker triggers on last trade, using ClosePriceIndicator may be acceptable.
• If broker triggers on bid/ask or mark/index price, use a matching indicator source.
• Do not mix trigger source and backtest source silently.

2) Decide bar-close vs intrabar evaluation

• Bar-close only:
  • Fewer false triggers, easier reproducibility.
  • Slower reaction.
• Intrabar (tick/stream updates):
  • Faster protection.
  • More noise and higher order churn.

Pick one model explicitly and keep it consistent between research and production.

3) Protect against gaps and slippage

• Stops are trigger conditions, not guaranteed fills.
• Plan with slippage cushions:
  • tighter position sizing,
  • broker-native stop/stop-limit where possible,
  • exchange outage safeguards.

4) Avoid stop churn

• Trailing rules can move often in noisy markets.
• Add guardrails:
  • minimum update interval,
  • minimum stop delta before replace,
  • cancel/replace rate limits.

5) Keep a stop hierarchy

• Primary logic stop (strategy-level)
• Catastrophic fail-safe stop
• Portfolio kill-switch (max drawdown / exposure limit)

Do not rely on a single mechanism.

Parameter tuning tips

• ATR period:
  • shorter (7-14) reacts quickly,
  • longer (20-50) is smoother and slower.
• ATR coefficient:
  • lower values stop out earlier,
  • higher values reduce churn but increase average loss size.
• Trailing lookback (barCount where applicable):
  • short lookback tightens quickly,
  • long lookback gives trends more room.

Practical tuning workflow:

1. Optimize for robustness first, not max return.
2. Validate on multiple volatility regimes.
3. Compare with realistic fees/slippage.
4. Stress test gap days and high-spread windows.

Complementary risk gating rules (0.22.2+)

Use these with stop rules when you need stronger entry/exit constraints:

• RiskRewardRatioRule
  • Checks whether your current price/stop/target tuple satisfies a minimum reward-to-risk threshold.
  • Useful before entering trades that rely on dynamic stop/target indicators.
• OverOrEqualIndicatorRule
  • Same semantics as OverIndicatorRule, but inclusive (>=) for threshold boundaries.
  • Useful for exact trigger levels (for example, “allow signal when RSI is exactly 50”).
• UnderOrEqualIndicatorRule
  • Same semantics as UnderIndicatorRule, but inclusive (<=) for threshold boundaries.
  • Useful for exact lower bounds (for example, “allow exit when RSI is exactly 30”).
• OrWithThresholdRule
  • OR composition evaluated over a rolling threshold window (current bar included).
  • Useful when either of two confirmation signals can fire within the last N bars.

Rule rrGate = new RiskRewardRatioRule(close, stopPrice, targetPrice, true, 2.0);
Rule inclusiveState = new OverOrEqualIndicatorRule(rsi, 50);
Rule inclusiveOversold = new UnderOrEqualIndicatorRule(rsi, 30);
Rule delayedConfirm = new OrWithThresholdRule(macdCrossUp, breakoutRule, 3);

Rule entryRule = rrGate.and(inclusiveState).and(inclusiveOversold.negation()).and(delayedConfirm);

Common mistakes

• Using fixed % stops on instruments with changing volatility regimes and no adaptive fallback.
• Using adaptive stops without a maximum loss cap.
• Overfitting stop parameters to one market period.
• Backtesting on close-only, then trading on tick-level without recalibration.
• Ignoring order semantics (partial fills, reduce-only, stop-limit miss risk).

Live deployment checklist

• Confirm stop trigger source (last, bid/ask, mark/index) matches indicator input.
• Confirm order type behavior on your venue.
• Confirm replacement throttling and retry logic.
• Confirm persistence and restart behavior for open positions and trailing state.
• Confirm metrics/alerts for stop-trigger frequency, slippage, and rejected orders.

See also:

• Trading Strategies
• Live Trading
• Backtesting

Maintainer rationale notes

• Stop-rule family coverage mirrors the expanded hierarchy added in commit 89cd2271 (BaseVolatility*, fixed-amount, trailing, and stop-price model interfaces).
• ATR constructor guidance reflects commit 1fa097ef and current AverageTrueRange* constructors that accept ATRIndicator directly.
• Added positive-coefficient note for AverageTrueRangeTrailingStopGainRule based on its input validation in requirePositiveAtrCoefficient(...).