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Gap Fill Reversal Strategy

Gap Fill Reversal takes advantage of overnight gaps that quickly retrace during the next session. When price gaps away from the prior close but immediately moves back to fill that void, it often signals an exhaustion of the initial move.

Testing indicates an average annual return of about 181%. It performs best in the crypto market.

The strategy enters once the gap is fully closed and looks for a reversal in the opposite direction of the open. It aims to capture the snap back that occurs as trapped traders exit their positions.

A percent-based stop defines the risk and positions close when momentum fades or the stop is hit.

Details

  • Entry Criteria: pattern match
  • Long/Short: Both
  • Exit Criteria: stop-loss or opposite signal
  • Stops: Yes, percent based
  • Default Values:
    • CandleType = 15 minute
    • MinGapPercent = 0.02 A gap is an open at least MinGapPercent away from the previous candle's close; the market trades around the clock, so gaps are measured between consecutive candles. The gap is filled when the same candle trades back to that close, and the opposite signal reverses the position.
    • StopLossPercent = 2
  • Filters:
    • Category: Pattern
    • Direction: Both
    • Indicators: Gap
    • Stops: Yes
    • Complexity: Intermediate
    • Timeframe: Intraday
    • Seasonality: No
    • Neural networks: No
    • Divergence: No
    • Risk level: Medium
using System;
using System.Collections.Generic;

using Ecng.Common;

using StockSharp.Algo.Indicators;
using StockSharp.Algo.Strategies;
using StockSharp.BusinessEntities;
using StockSharp.Messages;

namespace StockSharp.Samples.Strategies;

/// <summary>
/// Gap Fill Reversal strategy.
/// A gap is an open at least MinGapPercent away from the previous close. When the same candle trades back to the previous close,
/// filling the gap, the position turns against the gap: short after a gap up, long after a gap down. A percent stop limits the loss.
/// </summary>
public class GapFillReversalStrategy : Strategy
{
	private readonly StrategyParam<decimal> _minGapPercent;
	private readonly StrategyParam<decimal> _stopLossPercent;
	private readonly StrategyParam<DataType> _candleType;

	private decimal? _prevClose;

	/// <summary>
	/// Minimum gap between the previous close and the open, in percent.
	/// </summary>
	public decimal MinGapPercent
	{
		get => _minGapPercent.Value;
		set => _minGapPercent.Value = value;
	}

	/// <summary>
	/// Stop-loss percentage.
	/// </summary>
	public decimal StopLossPercent
	{
		get => _stopLossPercent.Value;
		set => _stopLossPercent.Value = value;
	}

	/// <summary>
	/// Candle type.
	/// </summary>
	public DataType CandleType
	{
		get => _candleType.Value;
		set => _candleType.Value = value;
	}

	/// <summary>
	/// Constructor.
	/// </summary>
	public GapFillReversalStrategy()
	{
		_minGapPercent = Param(nameof(MinGapPercent), 0.02m)
			.SetGreaterThanZero()
			.SetDisplay("Min Gap %", "Minimum gap between the previous close and the open", "Pattern");

		_stopLossPercent = Param(nameof(StopLossPercent), 2m)
			.SetNotNegative()
			.SetDisplay("Stop Loss %", "Stop loss percentage from entry price", "Risk");

		_candleType = Param(nameof(CandleType), TimeSpan.FromMinutes(15).TimeFrame())
			.SetDisplay("Candle Type", "Type of candles to use", "General");
	}

	/// <inheritdoc />
	public override IEnumerable<(Security sec, DataType dt)> GetWorkingSecurities()
	{
		return [(Security, CandleType)];
	}

	/// <inheritdoc />
	protected override void OnReseted()
	{
		base.OnReseted();
		_prevClose = null;
	}

	/// <inheritdoc />
	protected override void OnStarted2(DateTime time)
	{
		base.OnStarted2(time);

		_prevClose = null;

		var subscription = SubscribeCandles(CandleType);
		subscription
			.Bind(ProcessCandle)
			.Start();

		StartProtection(new Unit(), new Unit(StopLossPercent, UnitTypes.Percent), useMarketOrders: true, isLocalStop: true);

		// The stop has to see prices between candles, not only at their close.
		foreach (var field in new[] { Level1Fields.BestBidPrice, Level1Fields.BestAskPrice })
		{
			var quotes = new Subscription(DataType.Level1, Security);
			quotes.MarketData.BuildField = field;
			SubscribeLevel1(quotes).Bind(ObserveProtectionQuote).Start();
		}

		var area = CreateChartArea();
		if (area != null)
		{
			DrawCandles(area, subscription);
			DrawOwnTrades(area);
		}
	}

	private void ObserveProtectionQuote(Level1ChangeMessage quote)
	{
		// The high-level handler activates native protection before this callback, also between signal bars.
	}

	private void ProcessCandle(ICandleMessage candle)
	{
		if (candle.State != CandleStates.Finished)
			return;

		var prevClose = _prevClose;
		_prevClose = candle.ClosePrice;

		if (prevClose is not decimal last || last <= 0 || !IsFormedAndOnlineAndAllowTrading())
			return;

		var gap = (candle.OpenPrice - last) / last * 100m;

		if (gap >= MinGapPercent && candle.LowPrice <= last && Position >= 0)
			SellMarket(Volume + Math.Abs(Position));
		else if (-gap >= MinGapPercent && candle.HighPrice >= last && Position <= 0)
			BuyMarket(Volume + Math.Abs(Position));
	}
}