Portfolio Heat: Measure Total Open-Trade Risk Before Stops Hit Together

Portfolio Heat: Measure Total Open-Trade Risk Before Stops Hit Together

Position sizing controls the risk of one trade. Portfolio heat asks what happens when several open trades move against you at the same time. It adds the planned loss to each stop, then tests whether correlation, gaps, slippage or leverage could make the combined loss larger.

বাংলায় পড়ুন: Portfolio Heat: একসঙ্গে Stop Hit হলে Total Open Risk মাপুন

Learning objective: By the end of this tutorial, you should be able to calculate risk at stop for each position, express total open risk as a percentage of account equity, group related exposures and add a gap-and-slippage stress test before accepting another trade.

1. Define risk at stop for one position

For a simple long position:

Risk at stop = (entry price − stop price) × quantity + estimated exit costs.

For a short position, reverse the price difference. Futures require the contract's point value; FX requires pip value and currency conversion; options require a scenario-based revaluation because their price does not move one-for-one with the underlying.

Example:

• Entry: £50
• Stop: £48
• Quantity: 200 shares
• Estimated spread, slippage and fees on exit: £30

Risk at stop = (£50 − £48) × 200 + £30 = £430.

This is a planning estimate. A stop order does not guarantee a £48 fill during a gap, halt or fast market.

2. Define portfolio heat

The conservative starting calculation is:

Portfolio heat = sum of risk at stop for all open trades ÷ current account equity.

If a £50,000 account has £1,800 of combined risk at stop:

Portfolio heat = £1,800 ÷ £50,000 = 3.60%.

The percentage is not a universal acceptable limit. It is a common scale for comparing the current book with the trader's own tested risk policy.

Use current equity, not the original deposit. After a drawdown, the same £1,800 risk represents a larger percentage of the remaining account.

3. A worked four-position example

Assume a hypothetical £50,000 account holds four trades:

Position	Risk at planned stop	Account risk
Gold	£400	0.80%
Nasdaq-100	£500	1.00%
Bitcoin	£600	1.20%
WTI crude oil	£300	0.60%
Total	£1,800	3.60%

The arithmetic is simple. The interpretation is not. Nasdaq and Bitcoin may respond to the same risk-on/risk-off catalyst, while gold and oil can both react to the dollar, rates or geopolitical news. Four tickers are not necessarily four independent risks.

Before adding a fifth trade, calculate heat after the proposed position. A new trade risking £500 would raise planned heat from 3.60% to 4.60% if nothing else changed.

4. Group heat by common driver

Add a second view that groups positions by factor or theme:

Risk group	Positions	Risk at stop	Account risk
Growth and liquidity	Nasdaq-100, Bitcoin	£1,100	2.20%
Commodities and macro	Gold, WTI	£700	1.40%

This grouping is deliberately simple. Real exposures can overlap: oil influences inflation expectations, rates affect technology valuations, and dollar moves can reach every asset in the table.

Useful group labels include:

• equity beta;
• technology and AI;
• duration and interest rates;
• US dollar sensitivity;
• commodities and inflation;
• crypto liquidity;
• geography or currency;
• one event, such as CPI or a central-bank decision.

Set limits by the risks that can fail together, not only by ticker count.

5. Do not net long and short risk too easily

A long technology stock and a short equity index may appear hedged, but the hedge ratio can change. The stock may gap on earnings while the index is closed, or both legs may lose because of basis, borrow or execution differences.

Track at least three numbers:

1. Gross heat — sum of all planned stop losses without netting.
2. Directional or factor heat — exposure after a defensible hedge estimate.
3. Stressed heat — loss under a common adverse scenario with weaker correlations and worse execution.

Gross heat is intentionally conservative. Net heat can help explain the portfolio, but it should not erase the operational risk of closing both legs.

6. Add a gap-and-slippage stress test

The planned £1,800 heat assumes stops execute near their levels. Apply hypothetical stress multipliers based on each market's gap, liquidity and leverage risk:

Position	Planned risk	Illustrative stress multiplier	Stressed loss
Gold	£400	1.25×	£500
Nasdaq-100	£500	1.50×	£750
Bitcoin	£600	2.00×	£1,200
WTI crude oil	£300	1.50×	£450
Total	£1,800	—	£2,900

Stressed heat is:

£2,900 ÷ £50,000 = 5.80%.

The multipliers are examples, not recommended settings. Estimate them from historical gaps, adverse excursion, real slippage and instrument-specific market structure. Crypto trades continuously but can move sharply; futures can gap across maintenance windows; individual shares can jump across earnings; leveraged derivatives can liquidate before a planned stop.

7. Include orders that have not filled yet

Pending orders can create hidden heat. A stop-entry order may trigger while the trader is away, and several correlated orders may fill during the same market move.

Maintain separate totals for:

• current open-position heat;
• potential heat from pending orders;
• heat if every eligible signal fills;
• heat after planned reductions or hedges.

If four breakout orders all depend on a weaker dollar, assuming only one will fill may understate the risk.

8. Update heat as the trade changes

Portfolio heat is not fixed at entry.

Price moves towards the stop

Equity falls and the remaining distance to the stop changes. Depending on how risk is measured, the loss from current equity to stop may shrink while realised drawdown has already reduced the account base.

Stops move

A trailing stop can reduce planned risk, but only if it can execute. Moving a stop further away increases heat and should be treated like adding exposure.

Partial exits

Reducing quantity lowers risk at stop. Recalculate with the remaining size and new estimated costs.

Volatility changes

The same price stop may become too tight or too exposed after volatility rises. Review the ATR and volatility-adjusted position sizing guide for volatility-based distance and sizing.

Currency moves

A sterling account holding dollar, yen or euro exposures needs updated FX conversion. The local-currency risk can change even if the instrument price does not.

9. Heat is different from margin

Margin answers how much collateral the broker requires. Portfolio heat estimates the loss if the risk plan fails to the stop or stress level.

A trade can use little margin but carry large gap risk. Conversely, a fully paid position can still contribute significant portfolio heat. Broker liquidation rules can close a leveraged position before the trader's stop is reached.

Track both:

• risk budget, based on potential loss;
• margin utilisation, based on collateral and liquidation mechanics.

For the distinction, see Leverage, Margin and Liquidation Risk Explained.

10. Use risk buckets before accepting a trade

A practical pre-trade gate can ask:

1. What is the new trade's risk at stop, including realistic costs?
2. What will gross heat be after entry?
3. Which existing positions share its main driver?
4. What will group heat become?
5. What happens under the portfolio's gap-and-slippage stress?
6. Could pending orders also trigger?
7. Is enough liquidity available to exit the whole cluster?

If a new signal exceeds a risk bucket, choices include reducing its size, reducing an existing position, waiting for another trade to close or rejecting the setup. The signal's quality does not remove the capacity of the account to absorb loss.

11. Common mistakes

Adding position percentages instead of loss estimates

A 10% portfolio weight is not the same as 10% account risk. Risk depends on stop distance, volatility, leverage and instrument value.

Assuming every stop fills exactly

Stops are execution instructions, not price guarantees. Add gap and slippage scenarios.

Treating different tickers as diversification

Several assets can share one macro factor. Group exposure by likely failure mode.

Netting hedges at 100%

Basis, timing, liquidity and correlation can break. Keep a gross view.

Ignoring pending orders

Several conditional orders can trigger together and create more heat than the open book shows.

Using starting balance as the denominator

Risk should respond to current equity and realised drawdown.

Forgetting currency and contract multipliers

Convert all risk into the account's base currency and verify futures, options or CFD contract values.

12. Practical checklist

• Calculate price-to-stop loss for every open position.
• Add spread, slippage, fees and financing where material.
• Convert all risks to one base currency.
• Divide total risk by current account equity.
• Group positions by factor, theme, event and correlation.
• Track gross, grouped and stressed heat separately.
• Include pending orders and simultaneous-signal scenarios.
• Apply instrument-specific gap and liquidity stresses.
• Recalculate after size, stop, volatility, currency or equity changes.
• Review margin and liquidation risk separately from stop risk.
• Test the policy against historical and simulated drawdowns.

The core lesson

Risk does not stop at the boundary of one trade. Portfolio heat turns several open positions into one account-level loss estimate, then asks how much worse the result could become if correlations rise and stops slip.

The goal is not to predict the exact next loss. It is to keep one cluster of trades from becoming an account-level surprise.

Educational risk disclosure

This tutorial was prepared with AI-assisted research and writing under The Money Man editorial workflow. All positions, multipliers and account values are hypothetical and provided only to explain the method. This is educational information, not personalised investment advice or a universal risk limit. Stops may fill away from their trigger, markets can gap or halt, and leveraged losses can exceed the amount initially deposited.