The Position Sizing Mistake That Bankrupts Most Traders

0:03Trading with fixed share size, buying a 100 shares of every stock regardless of price or stop distance, is how retail traders bankrupt themselves. Fixed dollar sizing, risking the same dollar amount on every trade, regardless of account size, is only marginally better. Both ignore the math that determines whether a strategy survives variance.

0:25There's a single rule that fixes the death spiral and lets your edge compound. Percent risk sizing. Today, why fixed sizing is mathematically broken. The percent risk rule that survives any reasonable losing streak. And how proper sizing turns a profitable edge into actual wealth instead of an account blowup. Here's the formula.

0:47Position size equals account size times risk percent divided by the dollar distance to your stop. Pick a risk percent, usually 1/ half of 1% for beginners up to 1% for experienced traders. That percent is fixed across every trade. The share count varies trade by trade based on stop distance.

1:07Wide stop on a volatile stock, smaller share count, same total risk. Tight stop on a quiet stock, larger share count, same total risk. Every trade exposes the same percent of capital regardless of price or volatility. That constancy is what lets math beat variance over time. Watch this. In a synthetic equity curve, a trader buys a 100 shares of every stock, ignoring stop distance. On a tight stop trade, they risk 1% of account. On a wide stop trade, they risk 5%. Over 20 trades, the wider stop trades accumulate disproportionate losses. A single bad streak, three to four losses in a row on the wide stop trades wipes out 20% of the account. The strategy might have positive expectancy, but the sizing destroys the math. Fixed shares makes one trade's risk completely incomparable to anothers. Here's the rule that survives. Constant risk percent, variable share count. Every trade you take risks the same fraction of account, 1% or half a percent or 2% depending on your conviction tier. Share count adjusts to fit. A stop 50 cents away on a $10 stock gets 2,000 shares per percent risked. A stop $5 away on a $100 stock gets 200 shares per percent risked. Same risk in dollars, same risk in account percentage, same survival math regardless of which trade you took.

2:35Now with percent risk sizing, same strategy, same trades, but each trade now risks 1%. The losses are proportional, the wins are proportional. A four trade losing streak now costs 4% of account, not 20. The same edge plays out on a smooth recoverable equity curve instead of a death spiral curve. Over time, the compounding works in your favor over short streaks. You survive the variance. This is the difference between traders who last 5 years and traders who last 5 months. The math is identical. The sizing decides which curve you're riding. In real practice, build one spreadsheet cell that calculates position size from account size, risk percent, entry price, and stop price. Plug in those four numbers before every trade. The output is your share count. Use it exactly. Don't round up because the number looks small. Don't size up because you're convinced. The constant risk rule only works if it's actually constant. The first time you deviate, you've reintroduced the variance that kills accounts.

3:36So fixed share or fixed dollar sizing makes draw down spiral. Percent risk sizing, constant percent of account, variable share count is the single rule that lets a positive expectancy strategy survive variance long enough to compound. Calculate every position before clicking. The boring math is the wealth-b buildinging math. Subscribe for the full method and trade your own plan.

4:00Education, not financial advice.