⚠️ Educational research and a personal trading journal — not investment advice. การศึกษาเท่านั้น ไม่ใช่คำแนะนำการลงทุน. The author does not provide licensed advisory services. Investing involves risk; consult a licensed adviser before acting.
Most traders obsess over what to buy. Far fewer ask the question that actually determines whether they survive: how much do I put on each trade?
It sounds boring. It's the single biggest lever you control — bigger than your entry, bigger than your stop, arguably bigger than your strategy. So I tested it, properly, with real money math.
I took my breakout method, a real validated edge, and ran a ₿1,000,000 portfolio through 21 years of data — same trades, same exits, only the position size changing. Here's what 1 million baht became under each rule, and the lesson hiding in the numbers.
The results
| Risk per trade | ₿1M became | Worst drawdown |
|---|---|---|
| 0.25% | ₿1.68M | −9% |
| 0.5% | ₿2.63M | −17.6% |
| 1.0% | ₿4.87M | −27% |
| 2.0% | ₿4.18M | −29% |
Look at the last two rows. Going from 1% risk to 2% risk — doubling your bet size — made you less money and gave you bigger drawdowns.
That's not a typo. That's the most important thing in this entire post.
Why betting more makes you less
It feels like return should scale with risk. Bet twice as much, make twice as much, right?
Wrong — because losses don't add, they compound against you. Lose 50% and you need a 100% gain just to get back to even. The bigger your bets, the deeper your drawdowns, and the deeper your drawdowns, the more of your gains get eaten just clawing back to the high-water mark.
Past a certain point, every increase in bet size adds drawdown faster than it adds return. The return curve doesn't keep rising — it peaks and rolls over. In my test, the peak was around 1% risk per trade. Beyond that, you're not being aggressive; you're being inefficient.
This is the mathematical heart of "risk of ruin," and it's why professional traders who could bet huge choose to bet small.
The sweet spot: it's smaller than your ego wants
The best return-for-the-pain — the smoothest ride for the growth you get — landed around 0.5% risk per trade.
At 0.5%, ₿1M grew to ₿2.63M with a manageable −17.6% drawdown and a much steadier equity curve. You give up some raw return versus the 1% setting, but you cut the worst drawdown meaningfully and you're far more likely to stay in the game — psychologically and financially — through the rough patches.
And there will be rough patches. My method bled for three straight years (2022–2024) in a weak Thai market. At 2% risk, that stretch is a portfolio-threatening −29% hole. At 0.5%, it's an uncomfortable but survivable dip you trade through. Survival is the prerequisite for compounding. You can't win the long game if a bad year takes you out.
What "risk 0.5%" actually means
It's simple math, and it automatically sizes every trade for you:
Position size = (0.5% × your account) ÷ (entry price − stop price)
If you have a ₿1M account and your stop is 7% below your entry, you risk ₿5,000, which means a position of about ₿71,000 — roughly 7% of your account in that one stock. Tighter stop → bigger position; wider stop → smaller. The risk stays fixed at 0.5% no matter what. That's the point: you're holding your risk constant and letting the chart decide the size.
The real lesson
The trader who risks 0.5% and the trader who risks 2% can run the exact same strategy and end up in completely different places — one compounding steadily for a decade, the other blown up in a bad year. Same edge. Different size. Different life.
Bet small. Cut losers fast. Let winners run. The edge is real but thin and lumpy — size it like it could be wrong, because half the time, it is.
Track. Study. Wait. Strike. — and size like you intend to be here in ten years.
Personal research and trading journal, not investment advice. The author does not provide licensed advisory services. Markets carry risk; your decisions are your own. — MOEasymmetry