Risk Management

Stop-losses are one tool within risk management — not the entire system. A stop-loss controls single-trade loss. Risk management governs: how much capital is at risk across all trades simultaneously (portfolio heat), how large individual positions can be relative to account size, whether trading should pause after a losing streak, and how to size down systematically after drawdowns. Traders who set stops but ignore portfolio heat, daily limits, and drawdown rules have position-level risk management without portfolio-level risk management.

Position sizing is where risk management becomes quantitative. Given a trade setup with a defined entry and stop-loss, position size determines how many shares to buy so that the maximum loss equals a specific percentage of capital.

Fixed fractional sizing: Risk a fixed percentage of current account equity per trade (commonly 0.5-2%). On a $50,000 account risking 1%, the maximum loss per trade is $500. If the stock entry is $100 and the stop is at $97, the risk per share is $3. Maximum shares = $500 / $3 = 166 shares. This method scales position size with account equity — winning streaks produce larger absolute sizes, losing streaks produce smaller ones, naturally managing drawdowns.

ATR-based sizing: Position size is inversely proportional to the stock's average true range (ATR). More volatile stocks get smaller positions; less volatile stocks get larger positions. This ensures each position carries approximately equal risk in volatility-adjusted terms, regardless of price level or sector. A 2-ATR stop on a high-volatility biotech and a 2-ATR stop on a low-volatility utility result in similar dollar risk.

Kelly criterion: A mathematical formula that maximizes long-term geometric growth by allocating capital proportional to edge: f = (win_rate - (loss_rate / win_loss_ratio)). In practice, full Kelly sizing is extremely volatile. Most professional traders use half-Kelly or quarter-Kelly to reduce the variance while capturing most of the long-term growth benefit.

When to override sizing: During drawdown periods, volatility spikes, or when taking an unfamiliar setup type, reduce position size to 50% of normal. The expected value of a trade does not justify using full size when confidence is lower or market conditions are less favorable than typical.

Drawdowns are inevitable in any trading system. The goal of drawdown management is to ensure that losing streaks do not permanently impair your ability to trade or your psychological capacity to execute the system.

The mathematics of drawdown recovery: Drawdowns are asymmetric. A 10% loss requires an 11.1% gain to recover. A 25% loss requires a 33.3% gain. A 50% loss requires a 100% gain. This asymmetry means protecting against large drawdowns is mathematically far more valuable than extracting extra returns from good periods.

Drawdown-based position reduction: When drawdown from equity peak reaches 10%, reduce position size to 75% of normal. At 15% drawdown, reduce to 50%. At 20% drawdown, drop to 25% and consider pausing trading entirely to re-evaluate strategy health. This approach ensures you are risking less capital when your system is performing worst — exactly the opposite of revenge trading.

Strategy-level drawdown tracking: Track drawdown separately for each strategy you run. If your momentum strategy reaches a 15% strategy-level drawdown while your mean reversion strategy is performing normally, reduce momentum exposure specifically rather than cutting all trading. This allows you to continue participating in working strategies while protecting against deteriorating ones.

The psychological dimension: Drawdowns affect decision-making quality. Research shows that traders under stress from losses make progressively worse decisions: cutting winners early, widening stops on losers, and taking unplanned setups to recover losses. Daily loss limits enforce a hard stop before the psychological spiral can begin. Many professional traders consider the daily loss limit as important as any other risk rule — it protects the system from its own operator.

Risk management principles are universal, but implementation differs by strategy type and timeframe:

Day trading risk management: Day traders face the highest frequency of risk decisions. Key rules: close all positions by end of day (eliminating overnight gap risk), enforce a hard daily loss limit of 2-3%, use tight stops based on intraday support/resistance, and cap portfolio heat at 6-8% given the absence of overnight risk.

Swing trading risk management: Swing traders hold positions overnight and over weekends, introducing gap risk that stops cannot protect against. Key adjustments: reduce max position size by 30-50% relative to day trading, use wider stops based on daily ATR to avoid getting stopped out by normal intraday volatility, size down before binary events (earnings, economic data), and maintain a cash reserve of at least 20-30% to deploy into high-conviction setups without overextending.

Options risk management: Options positions require additional dimensions of risk tracking. Delta exposure measures directional risk (positive delta = long exposure). Vega exposure measures sensitivity to volatility changes. Theta tracks time decay. A portfolio concentrated in long options positions carries substantial theta burn risk — the portfolio loses value every day simply from time passing. Cap premium at risk (total options cost) at 2-5% of account per position and 10-15% aggregate.