Portfolio Heat

Portfolio heat is the sum of dollar risk across every open position, expressed as a percentage of total account equity. For each position, risk equals the dollar distance from entry price to stop-loss, multiplied by the number of shares held. A 100-share position in a $50 stock with a stop at $48 carries $200 of risk. If the account has $50,000 in equity, that single position contributes 0.4% of portfolio heat. When you have multiple open positions, their individual heat values are added together. A portfolio with five positions each carrying 1.2% risk has a total heat of 6%. Tracking this in real-time requires knowing the current stop-loss level — or planned initial stop — for every open position simultaneously.

Most traders focus on individual position sizing — risking 1% per trade — without aggregating risk across all open positions simultaneously. This becomes dangerous during correlated market sell-offs. If you have ten positions each risking 1%, they may all hit their stops on the same day during a broad market decline. That ten percent drawdown in a single session can be psychologically devastating and materially impair your ability to continue trading. Portfolio heat caps prevent this by ensuring that even in the worst realistic scenario — every position hitting its stop simultaneously — the total damage is bounded. Professional traders typically cap heat at 5 to 10 percent of equity, reducing the cap further after a losing streak or during elevated-volatility environments.

Not all heat is equal. Five positions in five different sectors carry less correlated risk than five positions in semiconductor stocks, even if the headline heat percentage is identical. Sophisticated portfolio heat management accounts for correlation by assigning higher heat weights to positions in the same sector, same factor exposure, or positions with high historical co-movement. During trending markets where momentum strategies perform well, running slightly elevated heat is reasonable. During choppy or transitioning regimes — after a sudden volatility spike, or when the market regime indicator shifts — reducing heat proactively is more prudent than waiting to be stopped out. These are educational guidelines; individual risk tolerance and account size are critical variables that every trader must assess independently.

The appropriate heat level differs significantly by strategy type. Day traders who close all positions by market close face risk only during intraday sessions and can tolerate slightly higher heat because the overnight gap risk is absent. Swing traders holding positions overnight and over weekends face gap risk — prices can open far beyond stop-loss levels — making more conservative heat management essential. Options traders must also account for vega risk, where a volatility spike can increase the dollar value of losses beyond what the delta-based stop implies. A practical framework: day traders cap heat at 6 to 8 percent, swing traders at 4 to 6 percent, and options-heavy portfolios at 2 to 4 percent due to the non-linear risk profile of options positions.