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Short-Term Reversal Stocks

The Short-Term Reversal Stocks strategy applies mean reversion principles to equities. Each day the stocks with the largest losses over the prior week are bought while recent winners are shorted, betting on a short-lived reversal.

Positions are held for only a few days before re-evaluating.

Details

  • Entry Criteria: Daily ranking by one-week return.
  • Long/Short: Both directions.
  • Exit Criteria: Positions closed after several days or when rankings update.
  • Stops: Volatility-based stop may be used.
  • Default Values:
    • CandleType = TimeSpan.FromMinutes(5).TimeFrame()
  • Filters:
    • Category: Mean reversion
    • Direction: Both
    • Indicators: Price based
    • Stops: Yes
    • Complexity: Basic
    • Timeframe: Short-term
    • 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.Configuration;
using StockSharp.Messages;

namespace StockSharp.Samples.Strategies;

/// <summary>
/// Short-term reversal strategy for stocks that trades the primary stock when its recent return overshoots or undershoots a benchmark stock.
/// </summary>
public class ShortTermReversalStocksStrategy : Strategy
{
	private readonly StrategyParam<string> _security2Id;
	private readonly StrategyParam<int> _lookbackPeriod;
	private readonly StrategyParam<int> _normalizationPeriod;
	private readonly StrategyParam<decimal> _entryThreshold;
	private readonly StrategyParam<decimal> _exitThreshold;
	private readonly StrategyParam<int> _cooldownBars;
	private readonly StrategyParam<decimal> _stopLoss;
	private readonly StrategyParam<DataType> _candleType;

	private Security _benchmark = null!;
	private RateOfChange _primaryReturn = null!;
	private RateOfChange _benchmarkReturn = null!;
	private SimpleMovingAverage _spreadAverage = null!;
	private StandardDeviation _spreadDeviation = null!;
	private decimal _latestPrimaryReturn;
	private decimal _latestBenchmarkReturn;
	private decimal? _previousZScore;
	private bool _primaryUpdated;
	private bool _benchmarkUpdated;
	private int _cooldownRemaining;

	public string Security2Id
	{
		get => _security2Id.Value;
		set => _security2Id.Value = value;
	}

	public int LookbackPeriod
	{
		get => _lookbackPeriod.Value;
		set => _lookbackPeriod.Value = value;
	}

	public int NormalizationPeriod
	{
		get => _normalizationPeriod.Value;
		set => _normalizationPeriod.Value = value;
	}

	public decimal EntryThreshold
	{
		get => _entryThreshold.Value;
		set => _entryThreshold.Value = value;
	}

	public decimal ExitThreshold
	{
		get => _exitThreshold.Value;
		set => _exitThreshold.Value = value;
	}

	public int CooldownBars
	{
		get => _cooldownBars.Value;
		set => _cooldownBars.Value = value;
	}

	public decimal StopLoss
	{
		get => _stopLoss.Value;
		set => _stopLoss.Value = value;
	}

	public DataType CandleType
	{
		get => _candleType.Value;
		set => _candleType.Value = value;
	}

	public ShortTermReversalStocksStrategy()
	{
		_security2Id = Param(nameof(Security2Id), Paths.HistoryDefaultSecurity2)
			.SetDisplay("Benchmark Security Id", "Identifier of the benchmark stock", "General");

		_lookbackPeriod = Param(nameof(LookbackPeriod), 5)
			.SetRange(2, 40)
			.SetDisplay("Lookback Period", "Recent return lookback period", "Indicators");

		_normalizationPeriod = Param(nameof(NormalizationPeriod), 16)
			.SetRange(5, 120)
			.SetDisplay("Normalization Period", "Lookback period used to normalize the reversal spread", "Indicators");

		_entryThreshold = Param(nameof(EntryThreshold), 1.1m)
			.SetRange(0.2m, 5m)
			.SetDisplay("Entry Threshold", "Z-score threshold required to open a position", "Signals");

		_exitThreshold = Param(nameof(ExitThreshold), 0.25m)
			.SetRange(0m, 2m)
			.SetDisplay("Exit Threshold", "Z-score threshold required to close a position", "Signals");

		_cooldownBars = Param(nameof(CooldownBars), 6)
			.SetRange(0, 120)
			.SetDisplay("Cooldown Bars", "Closed candles to wait before another position change", "Risk");

		_stopLoss = Param(nameof(StopLoss), 3m)
			.SetRange(0.5m, 10m)
			.SetDisplay("Stop Loss %", "Stop loss percentage", "Risk");

		_candleType = Param(nameof(CandleType), TimeSpan.FromHours(4).TimeFrame())
			.SetDisplay("Candle Type", "Time frame for candles", "General");
	}

	/// <inheritdoc />
	public override IEnumerable<(Security sec, DataType dt)> GetWorkingSecurities()
	{
		if (Security != null)
			yield return (Security, CandleType);

		if (!Security2Id.IsEmpty())
			yield return (new Security { Id = Security2Id }, CandleType);
	}

	/// <inheritdoc />
	protected override void OnReseted()
	{
		base.OnReseted();

		_benchmark = null!;
		_primaryReturn = null!;
		_benchmarkReturn = null!;
		_spreadAverage = null!;
		_spreadDeviation = null!;
		_latestPrimaryReturn = 0m;
		_latestBenchmarkReturn = 0m;
		_previousZScore = null;
		_primaryUpdated = false;
		_benchmarkUpdated = false;
		_cooldownRemaining = 0;
	}

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

		if (Security == null)
			throw new InvalidOperationException("Primary security is not specified.");

		if (Security2Id.IsEmpty())
			throw new InvalidOperationException("Benchmark security identifier is not specified.");

		_benchmark = this.LookupById(Security2Id) ?? new Security { Id = Security2Id };
		_primaryReturn = new RateOfChange { Length = LookbackPeriod };
		_benchmarkReturn = new RateOfChange { Length = LookbackPeriod };
		_spreadAverage = new SimpleMovingAverage { Length = NormalizationPeriod };
		_spreadDeviation = new StandardDeviation { Length = NormalizationPeriod };

		var primarySubscription = SubscribeCandles(CandleType, security: Security);
		var benchmarkSubscription = SubscribeCandles(CandleType, security: _benchmark);

		primarySubscription.Bind(ProcessPrimaryCandle).Start();
		benchmarkSubscription.Bind(ProcessBenchmarkCandle).Start();

		StartProtection(new Unit(2, UnitTypes.Percent), new Unit(StopLoss, UnitTypes.Percent));
	}

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

		var value = _primaryReturn.Process(candle);
		if (value.IsEmpty || !_primaryReturn.IsFormed)
			return;

		_latestPrimaryReturn = value.ToDecimal();
		_primaryUpdated = true;
		TryProcessSpread(candle.OpenTime);
	}

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

		var value = _benchmarkReturn.Process(candle);
		if (value.IsEmpty || !_benchmarkReturn.IsFormed)
			return;

		_latestBenchmarkReturn = value.ToDecimal();
		_benchmarkUpdated = true;
		TryProcessSpread(candle.OpenTime);
	}

	private void TryProcessSpread(DateTime time)
	{
		if (!_primaryUpdated || !_benchmarkUpdated)
			return;

		_primaryUpdated = false;
		_benchmarkUpdated = false;

		var spread = _latestPrimaryReturn - _latestBenchmarkReturn;
		var mean = _spreadAverage.Process(spread, time, true).ToDecimal();
		var deviation = _spreadDeviation.Process(spread, time, true).ToDecimal();

		if (!_spreadAverage.IsFormed || !_spreadDeviation.IsFormed || deviation <= 0m)
			return;

		if (!IsFormedAndOnlineAndAllowTrading())
			return;

		if (_cooldownRemaining > 0)
			_cooldownRemaining--;

		var zScore = (spread - mean) / deviation;
		var bullishEntry = _previousZScore is decimal previousBullish && previousBullish > -EntryThreshold && zScore <= -EntryThreshold;
		var bearishEntry = _previousZScore is decimal previousBearish && previousBearish < EntryThreshold && zScore >= EntryThreshold;

		if (_cooldownRemaining == 0 && Position == 0)
		{
			if (bullishEntry)
			{
				BuyMarket();
				_cooldownRemaining = CooldownBars;
			}
			else if (bearishEntry)
			{
				SellMarket();
				_cooldownRemaining = CooldownBars;
			}
		}
		else if (Position > 0 && zScore >= -ExitThreshold)
		{
			SellMarket(Position);
			_cooldownRemaining = CooldownBars;
		}
		else if (Position < 0 && zScore <= ExitThreshold)
		{
			BuyMarket(Math.Abs(Position));
			_cooldownRemaining = CooldownBars;
		}

		_previousZScore = zScore;
	}
}