position sizing
The process of determining how much capital to allocate to each investment based on risk tolerance, conviction level, and portfolio management rules.
Example
“His position sizing rule limited any single stock to 5% of his portfolio, preventing catastrophic loss from any one failure.”
Memory Tip
POSITION SIZING = how BIG a bet to make. Risk management through careful allocation.
Why It Matters
Position sizing directly impacts how much money you can lose on any single investment, which determines whether a bad trade ruins your finances or becomes a minor setback. By carefully sizing positions, you protect your overall portfolio from catastrophic losses and allow yourself to stay invested long enough to benefit from compounding returns over time.
Common Misconception
Many people believe that position sizing means investing equal amounts in every opportunity, but this ignores that different investments carry different risk levels and conviction levels. A stock you are highly confident in with lower volatility should typically receive a larger allocation than a speculative bet on a penny stock.
In Practice
If you have a $100,000 portfolio with a 2 percent risk limit per trade, you would risk only $2,000 maximum on any single position. If you want to buy a stock trading at $50 and plan to sell if it drops to $45 (a $5 risk per share), you could buy 400 shares ($20,000 position) to stay within your $2,000 maximum loss threshold.
Etymology
POSITION (investment holding) SIZING (determining the appropriate amount). How large to SIZE each investment POSITION.
Common Misspellings
Protect your assets with the right insurance
Related Terms
More in risk management
Other risk management terms you should know
Need financial definitions?
Clear definitions for 2,500+ finance, insurance, and investing terms.