Advanced Position Sizing
The 1% rule is a starting point — not the full picture. As your strategy gets more defined and your portfolio grows, a more nuanced approach to position sizing can significantly improve both returns and drawdown control. This lesson covers the framework used by professional traders.
Risk Per Trade vs. Portfolio Exposure
Two separate risk dimensions every trader needs to manage:
- Risk per trade: How much of your account can you lose on a single trade? (The 1% rule)
- Total portfolio exposure: What is the sum of all open position risks simultaneously? This is often ignored — and it's often what blows accounts.
Example: You have 5 open positions, each risking 2% of account. Your total exposure is 10%. If there's a market crash affecting all positions at once (correlation risk), you can lose 10% in a single event. This happens frequently in crypto where all coins move together.
Correlation Risk in Crypto
Crypto assets are highly correlated — especially during sell-offs. When BTC drops 10%, almost everything else drops with it, often more. This means:
- Having 5 "diversified" crypto positions is not actually diversification
- Your effective risk in a market panic is close to the sum of all your individual position risks
- Adjust your per-trade risk down when holding multiple positions simultaneously
The Volatility-Adjusted Position Size
Instead of always risking the same percentage per trade, volatility-adjusted sizing accounts for how erratic an asset is moving. The formula uses ATR (Average True Range):
| Input | Example A (Low Vol) | Example B (High Vol) |
|---|---|---|
| Account | €10,000 | €10,000 |
| Risk per trade (1%) | €100 | €100 |
| Entry price | €60,000 | €60,000 |
| ATR (daily) | €600 (1%) | €2,400 (4%) |
| Stop = 2× ATR | €1,200 | €4,800 |
| Position size | €100 / €1,200 = 0.083 BTC | €100 / €4,800 = 0.021 BTC |
High-volatility assets automatically get smaller positions — protecting you from outsized losses
Kelly Criterion — A Framework, Not a Formula
The Kelly Criterion is a mathematical formula for optimal bet sizing: f = (bp - q) / b, where b = odds, p = win probability, q = loss probability.
In trading terms, Kelly tells you the optimal fraction of your bankroll to risk given your edge. The problem: estimating your true edge precisely enough for Kelly to be useful is very difficult in practice.
Most professional traders use "half-Kelly" — betting half the Kelly-optimal amount. This dramatically reduces variance while giving up only a fraction of expected return. As a rule of thumb: if full Kelly says 8%, you trade 4%.
Scaling In vs. Full Position Entry
Rather than entering your full position at once, some traders scale in across 2–3 entries:
- First entry (50%): At the initial signal — you have exposure if the trade works immediately
- Second entry (30%): If price pulls back and confirms the level holds — better average entry
- Third entry (20%): On breakout from consolidation — confirms momentum
Risk management: each partial entry has its own stop, but the combined maximum risk across all entries should still not exceed your per-trade risk limit.
For most beginners, scaling in adds complexity without much benefit. Master full-position entries first.
Key Takeaways
- Manage both per-trade risk AND total portfolio exposure — especially in correlated markets
- In crypto, 5 open positions each risking 2% = effectively 10% correlated risk in a crash
- Volatility-adjusted sizing: use 2× ATR as stop distance — high-vol assets get smaller positions automatically
- Kelly Criterion gives optimal sizing given your edge — but requires 50+ trades of accurate data
- Use half-Kelly in practice: full Kelly is too aggressive for the variance levels in trading
- Scaling in can improve average entry but adds complexity — master simple entries first
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