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Low Volatility Stocks

Trading rules

Compute simple daily returns r[d] = P[d] / P[d−1] − 1 over VolWindowDays intervals using VolWindowDays + 1 completed daily closes. Volatility is the sample standard deviation sqrt(Σ(r−mean(r))² / (VolWindowDays−1)). Every month long the lowest-volatility Deciles bucket and short the highest, floor(eligible count / Deciles) securities per side. Equal USD exposure per side; no benchmark spread, trend gate or intraday volatility threshold.

Evaluate only synchronized finished candles. Statistics count distinct UTC dates, replacing earlier intraday closes of the same date. Rebalance once on the first eligible synchronized candle of each month; an unformed input delays the decision. Equal scores are ordered by Security.Id.

All observations must be published by the signal candle close. Intraday execution uses daily prices strictly before its UTC date; a finished one-day candle contributes its own completed date. Never warm a decision with future CSV dates.

Input data

PriceHistoryFile is an optional CSV of positive daily closes: SecurityId,Date,Close. Dates use yyyy-MM-dd. Current and future dates cannot prefill a decision; live finished closes replace each UTC date. Duplicate dates are rejected. It is needed to warm long lookbacks when the execution archive is short.

Parameters

Parameter Default
Universe required
Capital 100000
Leverage 1
MinTradeUsd 200
CandleType TimeSpan.FromDays(1).TimeFrame()
PriceHistoryFile optional — not supplied
VolWindowDays 60
Deciles 10

Execution

Set Universe explicitly. Prices and Capital use USD, with one price unit per traded unit. Capital is a fixed budget; Leverage controls gross exposure. No stop loss or take profit is added.

Long and short baskets each receive half of Capital × Leverage. Divide each side equally, convert USD to units at the signal close and round toward zero to VolumeStep. Reconcile against actual filled positions, wait for pending orders, respect MinVolume/MaxVolume and split large adjustments across later candles. MinTradeUsd filters small adjustments; full liquidation bypasses it.

Verification

Tests run both languages using packaged BTC/TON execution data and explicit rate, financial, score, text and warmup fixtures. Calendar fixtures relocate archive OHLC/volume and provide deterministic execution quotes; they are not multi-year market history. Independent formulas, order direction/size, actual fills, residual positions and forbidden decision dates are checked. Two buckets, K=1 and AssetDecile=1 are declared mechanics profiles, not evidence of the complete production universe. No profitability claim is made.

namespace StockSharp.Samples.Strategies;

using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;

using Ecng.Common;

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

/// <summary>Low Volatility Stocks with point-in-time inputs and execution-based portfolio accounting.</summary>
public class LowVolatilityStocksStrategy : Strategy
{
	private readonly StrategyParam<IEnumerable<Security>> _universe;
	private readonly StrategyParam<decimal> _capital;
	private readonly StrategyParam<decimal> _leverage;
	private readonly StrategyParam<decimal> _minTradeUsd;
	private readonly StrategyParam<DataType> _candleType;
	private readonly StrategyParam<string> _priceHistoryFile;
	private readonly StrategyParam<int> _volWindowDays;
	private readonly StrategyParam<int> _deciles;
	private Security[] _securities = [];
	private readonly Dictionary<Security, (DateTime time, decimal price)> _latest = [];
	private readonly Dictionary<Security, SortedDictionary<DateTime, decimal>> _history = [];
	private readonly Dictionary<Security, decimal> _targets = [];
	private readonly List<Order> _pending = [];
	private int _lastRebalance;
	private DateTime? _lastBar;

	/// <summary>Explicit execution securities with valid native volume metadata.</summary>
	public IEnumerable<Security> Universe { get => _universe.Value; set => _universe.Value = value; }

	/// <summary>Fixed capital budget in USD.</summary>
	public decimal Capital { get => _capital.Value; set => _capital.Value = value; }

	/// <summary>Gross target exposure divided by the capital budget.</summary>
	public decimal Leverage { get => _leverage.Value; set => _leverage.Value = value; }

	/// <summary>Minimum USD adjustment; complete liquidation bypasses this filter.</summary>
	public decimal MinTradeUsd { get => _minTradeUsd.Value; set => _minTradeUsd.Value = value; }

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

	/// <summary>Optional daily close CSV; future dates cannot prefill a decision.</summary>
	public string PriceHistoryFile { get => _priceHistoryFile.Value; set => _priceHistoryFile.Value = value; }

	/// <summary>Completed daily returns in the sample standard deviation.</summary>
	public int VolWindowDays { get => _volWindowDays.Value; set => _volWindowDays.Value = value; }

	/// <summary>Number of volatility buckets.</summary>
	public int Deciles { get => _deciles.Value; set => _deciles.Value = value; }

	/// <summary>Initialize the strategy parameters.</summary>
	public LowVolatilityStocksStrategy()
	{
		_universe = Param<IEnumerable<Security>>(nameof(Universe)).SetRequired()
			.SetDisplay("Universe", "Explicit execution securities with valid native volume metadata", "Parameters");
		_capital = Param(nameof(Capital), 100000m).SetGreaterThanZero()
			.SetDisplay("Capital", "Fixed capital budget in USD", "Parameters");
		_leverage = Param(nameof(Leverage), 1m).SetGreaterThanZero()
			.SetDisplay("Leverage", "Gross target exposure divided by the capital budget", "Parameters");
		_minTradeUsd = Param(nameof(MinTradeUsd), 200m).SetRange(0m, decimal.MaxValue)
			.SetDisplay("MinTradeUsd", "Minimum USD adjustment; complete liquidation bypasses this filter", "Parameters");
		_candleType = Param(nameof(CandleType), TimeSpan.FromMinutes(1440).TimeFrame())
			.SetDisplay("CandleType", "Finished execution candle type", "Parameters");
		_priceHistoryFile = Param<string>(nameof(PriceHistoryFile))
			.SetDisplay("PriceHistoryFile", "Optional daily close CSV; future dates cannot prefill a decision", "Parameters");
		_volWindowDays = Param(nameof(VolWindowDays), 60).SetRange(2, int.MaxValue)
			.SetDisplay("VolWindowDays", "Completed daily returns in the sample standard deviation", "Parameters");
		_deciles = Param(nameof(Deciles), 10).SetRange(2, int.MaxValue)
			.SetDisplay("Deciles", "Number of volatility buckets", "Parameters");
	}

	/// <inheritdoc />
	public override IEnumerable<(Security sec, DataType dt)> GetWorkingSecurities()
		=> (Universe ?? []).Where(s => s is not null).DistinctBy(s => s.Id, StringComparer.OrdinalIgnoreCase).Select(s => (s, CandleType));

	/// <inheritdoc />
	protected override void OnReseted()
	{
		base.OnReseted();
		_securities = [];
		_latest.Clear();
		_history.Clear();
		_targets.Clear();
		_pending.Clear();
		_lastRebalance = 0;
		_lastBar = null;
	}

	/// <inheritdoc />
	protected override void OnStarted2(DateTime time)
	{
		_securities = (Universe ?? []).ToArray();
		if (_securities.Length == 0 || _securities.Any(s => s is null || string.IsNullOrWhiteSpace(s.Id))
			|| _securities.Select(s => s.Id).Distinct(StringComparer.OrdinalIgnoreCase).Count() != _securities.Length)
			throw new InvalidOperationException("Universe must contain distinct execution securities.");
		foreach (var security in _securities)
		{
			if (security.VolumeStep is not > 0m || security.MinVolume is not > 0m || security.MaxVolume is not > 0m)
				throw new InvalidOperationException("Every security needs positive VolumeStep, MinVolume and MaxVolume.");
			_history[security] = [];
		}
		LoadPriceHistory();

		base.OnStarted2(time);
		foreach (var security in _securities)
			SubscribeCandles(CandleType, security: security).Bind(candle => ProcessCandle(security, candle)).Start();
	}

	private void ProcessCandle(Security security, ICandleMessage candle)
	{
		if (candle.State != CandleStates.Finished || candle.ClosePrice <= 0m) return;
		_latest[security] = (candle.OpenTime, candle.ClosePrice);
		_history[security][candle.OpenTime.Date] = candle.ClosePrice;
		if (_latest.Count != _securities.Length || _latest.Values.Any(v => v.time != candle.OpenTime)
			|| _lastBar == candle.OpenTime || !IsFormedAndOnlineAndAllowTrading()) return;
		_lastBar = candle.OpenTime;
		var month = candle.OpenTime.Year * 100 + candle.OpenTime.Month;
		if (_lastRebalance != month && SelectTargets(candle.OpenTime))
			_lastRebalance = month;
		ReconcileTargets();
	}

	private decimal Budget => Capital * Leverage;

	private DateTime AsOf(DateTime time)
		=> CandleType.Arg is TimeSpan frame ? time.Add(frame).AddTicks(-1) : time;

	private decimal UnitPrice(Security security) => _latest[security].price;

	private decimal Units(Security security, decimal notional)
		=> Math.Floor(notional / UnitPrice(security) / security.VolumeStep.Value) * security.VolumeStep.Value;

	private void ReconcileTargets()
	{
		if (_pending.Any(o => o.State is not (OrderStates.Done or OrderStates.Failed))) return;
		_pending.Clear();
		foreach (var security in _securities)
		{
			if (!_targets.TryGetValue(security, out var target)) continue;
			var delta = target - GetPositionValue(security, Portfolio).GetValueOrDefault();
			if (delta == 0m || (target != 0m && Math.Abs(delta) * UnitPrice(security) < MinTradeUsd)) continue;
			var step = security.VolumeStep.Value;
			var quantity = Math.Floor(Math.Min(Math.Abs(delta), security.MaxVolume.Value) / step) * step;
			if (quantity < security.MinVolume.Value) continue;
			var order = new Order
			{
				Security = security, Portfolio = Portfolio, Type = OrderTypes.Market,
				Side = delta > 0m ? Sides.Buy : Sides.Sell, Volume = quantity, Comment = "0377Rebalance",
			};
			_pending.Add(order);
			RegisterOrder(order);
		}
	}

	private static DateTime ParseUtc(string value)
		=> DateTime.ParseExact(value.Trim(), "yyyy-MM-dd'T'HH:mm:ss'Z'", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal);

	private static IEnumerable<string[]> ReadRows(string path, string header, int fields)
	{
		using var lines = File.ReadLines(path).GetEnumerator();
		if (!lines.MoveNext() || lines.Current.Trim() != header)
			throw new InvalidOperationException("Invalid CSV header: expected " + header + ".");
		while (lines.MoveNext())
		{
			if (string.IsNullOrWhiteSpace(lines.Current)) continue;
			var row = lines.Current.Split(',');
			if (row.Length != fields) throw new InvalidOperationException("Invalid CSV field count.");
			yield return row;
		}
	}

	private DateTime LastClosedDate(DateTime time)
		=> CandleType.Arg is TimeSpan frame && frame == TimeSpan.FromDays(1) ? time.Date : time.Date.AddDays(-1);

	private decimal[] Daily(Security security, DateTime time, int count, DateTime cutoff)
		=> _history[security].Where(x => x.Key <= LastClosedDate(time) && x.Key < cutoff).Select(x => x.Value).TakeLast(count).ToArray();

	private void LoadPriceHistory()
	{
		if (string.IsNullOrWhiteSpace(PriceHistoryFile)) return;
		foreach (var row in ReadRows(PriceHistoryFile, "SecurityId,Date,Close", 3))
		{
			var security = _securities.SingleOrDefault(s => string.Equals(s.Id, row[0].Trim(), StringComparison.OrdinalIgnoreCase));
			if (security is null) continue;
			var date = DateTime.ParseExact(row[1].Trim(), "yyyy-MM-dd", CultureInfo.InvariantCulture);
			var price = decimal.Parse(row[2], CultureInfo.InvariantCulture);
			if (price <= 0m || !_history[security].TryAdd(date, price))
				throw new InvalidOperationException("Daily prices must be positive and unique per security and UTC date.");
		}
	}

	private bool SelectTargets(DateTime time)
	{
		var scores = new List<(Security security, double score)>();
		foreach (var security in _securities)
		{
			var prices = Daily(security, time, VolWindowDays + 1, DateTime.MaxValue);
			if (prices.Length != VolWindowDays + 1) continue;
			var returns = prices.Skip(1).Select((p, i) => (double)(p / prices[i] - 1m)).ToArray();
			var mean = returns.Average();
			var deviation = Math.Sqrt(returns.Sum(r => (r - mean) * (r - mean)) / (VolWindowDays - 1));
			scores.Add((security, deviation));
		}
		if (scores.Count < Deciles) return false;
		var ranked = scores.OrderBy(x => x.score).ThenBy(x => x.security.Id, StringComparer.Ordinal).Select(x => x.security).ToArray();
		var count = ranked.Length / Deciles;
		SetBasketTargets(ranked.Take(count), ranked.TakeLast(count), Budget);
		return true;
	}

	private void SetBasketTargets(IEnumerable<Security> longBasket, IEnumerable<Security> shortBasket, decimal grossCapital)
	{
		var longs = longBasket.ToArray();
		var shorts = shortBasket.ToArray();
		foreach (var security in _securities) _targets[security] = 0m;
		foreach (var security in longs) _targets[security] = Units(security, grossCapital / (2m * longs.Length));
		foreach (var security in shorts) _targets[security] = -Units(security, grossCapital / (2m * shorts.Length));
	}
}