Position Sizing and Capital Management

Position sizing is arguably the most important aspect of trading success — more important than entry signals or indicator selection. Two traders can use the exact same strategy but achieve vastly different results based on how much they risk per trade. Position sizing determines how many shares to buy and, consequently, how much you stand to gain or lose. It is the bridge between a good strategy and a good result.

The 2% Rule is the most widely used position sizing method. It states: never risk more than 2% of your total portfolio on a single trade. If your portfolio is 100,000 EGP and you risk 2%, your maximum loss per trade is 2,000 EGP. Position size = Risk Amount / (Entry Price - Stop Loss Price). Example: if you buy a stock at 50 EGP with a stop at 46 EGP (risk per share = 4 EGP), position size = 2,000 / 4 = 500 shares. More conservative traders use 1% or even 0.5%.

R-Multiples standardize trade results relative to initial risk. 1R = the amount you initially risked on the trade. If you risked 2,000 EGP and made 6,000 EGP profit, the trade was a +3R winner. If you lost 2,000 EGP, it was a -1R loser. Expressing all trades in R-multiples makes it easy to compare strategies. A good trend-following system might have an average win of +3R to +5R and an average loss of -1R, even with a 40% win rate — the math works because big winners compensate for frequent small losses.

The Kelly Criterion calculates the mathematically optimal percentage of capital to risk: Kelly % = W - [(1-W) / R], where W = win rate (decimal) and R = average win/average loss ratio. Example: with 50% win rate and 2:1 win/loss ratio, Kelly = 0.50 - (0.50 / 2) = 0.25 (25%). However, full Kelly is extremely aggressive and assumes perfect knowledge of probabilities. Most practitioners use "Half Kelly" or "Quarter Kelly" to reduce volatility and account for estimation errors.

Portfolio-level risk management: Beyond individual position sizing, manage total portfolio risk. (1) Maximum portfolio heat — limit total risk across all open positions to 6-10% of portfolio. With 2% per trade, that means 3-5 open positions. (2) Sector concentration — avoid having more than 25-30% of your portfolio in a single sector. (3) Correlation risk — stocks in the same sector tend to move together, so five bank stocks are not truly diversified. (4) Cash allocation — keep 10-20% in cash as a reserve for new opportunities and to reduce drawdowns.

Scaling in and scaling out: Instead of committing your full position at once, consider building it gradually. Scale in: buy 1/3 of your intended position, and add more as the trade moves in your favor (at breakout confirmation, after pullback bounce). This reduces risk on initial entry. Scale out: sell 1/3 at the first target, move stop to breakeven, sell another 1/3 at the second target, and let the remaining 1/3 ride with a trailing stop. This locks in profits while maintaining upside exposure.

Position sizing for Egyptian stocks: (1) Account for the wider bid-ask spreads of EGX stocks — your effective entry and exit prices may differ from planned levels. (2) For small-cap stocks with daily volume under 1 million EGP, limit your position to a percentage of daily volume (e.g., 10-20%) to ensure you can exit without moving the market. (3) During market downturns, reduce position sizes proactively rather than waiting for stops to be hit. (4) Factor in brokerage fees (0.15-0.25%) and stamp tax when calculating risk. (5) FoudaLens helps with position sizing by providing ATR-based volatility data for all tracked stocks. This is not financial advice.