What it means
Position sizing is the decision of how many shares, contracts, or dollars to put behind any single idea. The Kelly criterion gives the mathematically optimal size given win rate and win/loss ratio, though most practitioners use fractional Kelly or fixed-percentage rules.
Why it matters
Position sizing matters more than entry timing. The same strategy with 1% risk per trade vs 10% risk per trade has wildly different long-run outcomes. Sizing is where strategies actually live or die.
How to use it
Start with a maximum risk per trade (commonly 1% of account). Set position size = risk_amount / (entry – stop). This anchors all decisions to risk, not dollar amount.
Want a worked example or a deeper dive? Ask Rocky how this concept applies to your specific watchlist or trade idea.
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