chore: import upstream snapshot with attribution

2026-07-13 13:02:50 +08:00
commit 0fc60fdcb1
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+/*
+ * QUANTCONNECT.COM - Democratizing Finance, Empowering Individuals.
+ * Lean Algorithmic Trading Engine v2.0. Copyright 2014 QuantConnect Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+*/
+
+using System;
+using System.Collections.Generic;
+using QuantConnect.Algorithm.Framework.Portfolio;
+
+namespace QuantConnect.Algorithm.Framework.Risk
+{
+    /// <summary>
+    /// Provides an implementation of <see cref="IRiskManagementModel"/> that limits the drawdown of the portfolio
+    /// to the specified percentage. Once this is triggered the algorithm will need to be manually restarted.
+    /// </summary>
+    public class MaximumDrawdownPercentPortfolio : RiskManagementModel
+    {
+        private readonly decimal _maximumDrawdownPercent;
+        private decimal _portfolioHigh;
+        private bool _initialised = false;
+        private bool _isTrailing;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="MaximumDrawdownPercentPortfolio"/> class
+        /// </summary>
+        /// <param name="maximumDrawdownPercent">The maximum percentage drawdown allowed for algorithm portfolio
+        /// compared with starting value, defaults to 5% drawdown</param>
+        /// <param name="isTrailing">If "false", the drawdown will be relative to the starting value of the portfolio.
+        /// If "true", the drawdown will be relative the last maximum portfolio value</param>
+        public MaximumDrawdownPercentPortfolio(decimal maximumDrawdownPercent = 0.05m, bool isTrailing = false)
+        {
+            _maximumDrawdownPercent = -Math.Abs(maximumDrawdownPercent);
+            _isTrailing = isTrailing;
+        }
+
+        /// <summary>
+        /// Manages the algorithm's risk at each time step
+        /// </summary>
+        /// <param name="algorithm">The algorithm instance</param>
+        /// <param name="targets">The current portfolio targets to be assessed for risk</param>
+        public override IEnumerable<IPortfolioTarget> ManageRisk(QCAlgorithm algorithm, IPortfolioTarget[] targets)
+        {
+            var currentValue = algorithm.Portfolio.TotalPortfolioValue;
+
+            if (!_initialised)
+            {
+                _portfolioHigh = currentValue; // Set initial portfolio value
+                _initialised = true;
+            }
+
+            // Update trailing high value if in trailing mode
+            if (_isTrailing && (_portfolioHigh < currentValue))
+            {
+                _portfolioHigh = currentValue;
+                yield break; // return if new high reached
+            }
+
+            var pnl = GetTotalDrawdownPercent(currentValue);
+            if (pnl < _maximumDrawdownPercent && targets.Length != 0)
+            {
+                // reset the trailing high value for restart investing on next rebalcing period
+                _initialised = false;
+                foreach (var target in targets)
+                {
+                    var symbol = target.Symbol;
+                    
+                    // Cancel insights
+                    algorithm.Insights.Cancel(new[] { symbol });
+
+                    // liquidate
+                    yield return new PortfolioTarget(symbol, 0);
+                }
+            }
+        }
+
+        private decimal GetTotalDrawdownPercent(decimal currentValue)
+        {
+            return (currentValue / _portfolioHigh) - 1.0m;
+        }
+    }
+}