Standard: 2% risk per trade. Formula: Position size = (Capital × 2%) / (Entry - Stop Loss). Example: Capital 100M, risk 2% = 2M. Entry VCB 100k, stop 92k → loss/share = 8k. Shares = 2M / 8k = 250 cp. Position value = 25M (25% capital). Calculator: /tools/position-size-calculator.
Optimal sizing based on edge + odds. Formula: f* = (bp - q) / b. b = win/loss ratio, p = win probability, q = 1-p. Example: Win rate 55%, R:R 1:2 → Full Kelly = 32.5%. Half Kelly recommend: 16% — Reduces volatility 50% while keeping 75% growth. Calculator: /tools/kelly-criterion-calculator.
Adjust size theo volatility. Formula: Position size = (Capital × 1%) / (ATR × multiplier). Example: ATR(14) VCB = 2,500. Multiplier 1.5 → ATR-stop = 3,750. Capital 100M, 1% risk = 1M. Shares = 1M / 3,750 = 266 cp. Advantage: Tighter sizing in volatile periods. Turtle Traders system.
Same dollar amount mỗi trade. Example: Always 10M VND/trade. Pros: Simple, beginner-friendly. Cons: Risk varies by stop distance. NOT recommended for serious traders.
10 positions = 10% each. 20 positions = 5% each. Pros: Simple. Cons: Treats all stocks equally — không adjust for conviction or volatility. Lazy man's portfolio.
Enter 1/3 ban đầu. Add 1/3 nếu +5%. Add 1/3 nếu +10%. Pros: Add to winners, average up. Cons: Capital intensive, complex tracking. Best for trend-following.
Beginner: Fixed % (2%) — simple, effective. Intermediate: Half Kelly — optimized growth. Advanced: ATR-based — volatility-adjusted. Multi-strategy: Combine — Kelly for high conviction, Fixed % for normal.
1) Position too large: 50% portfolio in 1 stock → 1 bad trade ruins year. 2) Doubling down on losers: "Sẽ recover" → 5x position in declining stock. 3) No stop loss: Position size meaningless without stop. 4) Emotional override: "Conviction this time" → break rules → blow up. 5) Over-leveraging: Margin 1:5 on penny stocks.
1) Before trade: Calculate exact shares qua /tools/position-size-calculator. 2) Set stop loss CHÍNH XÁC. 3) Total open risk < 6% capital. 4) Single position < 10% capital (except blue-chip with conviction high → max 20%). 5) Review weekly position distribution — không over-concentrate sector.