Every few months a friend asks me some version of the same question, usually right after their first good stretch of trading. They have some savings, the account is up, and they want to know how much more they should move in. The number they have in mind is almost always too big, and it is too big because they are sizing it off how confident they feel. The only question that should size a trading account is how much money you can watch go to zero without anything in your life changing.
That is the whole definition of risk capital, and it is stricter than most people want it to be. Money whose total loss, all of it, gone, changes nothing. Rent still goes out on the same day. The emergency fund is untouched. The timeline on the house deposit or the tuition does not move. Nobody in your household needs to be told anything. If losing the full amount would force even one decision you would not otherwise make, the money fails the test, no matter how good the current setup looks.
The common mistake is grading this on drawdown instead of total loss. People fund an account with money they could stand to see down 20 percent, because a 20 percent dip feels like the realistic bad case, and for an active trader it is nowhere near the bad case. If you trade frequently, and especially if you use leverage, the plausible worst outcome over a year or two is losing most or all of the account. Careful traders get there too, because losses cluster, liquidity disappears exactly when you need it, and venues and counterparties occasionally fail outright. I have watched disciplined people lose an entire account to an exchange collapse that had nothing to do with their trade selection. Fund the account as if zero is a live outcome, because over a long enough horizon it is.
Separate the money physically, then write down the rule for moving it
Mental accounting does not survive a losing streak. If your trading balance and your savings sit in the same account, or one click apart at the same institution, the boundary between them is a feeling, and feelings degrade at exactly the moment you need them to hold. So make the separation physical. Trading capital lives in its own account, ideally at a different institution, funded by an explicit transfer that takes a day to clear. The delay is useful on purpose, because most of the worst funding decisions in trading get made within an hour of a big loss, and a transfer that settles tomorrow gives the part of your brain that pays rent time to show up to the meeting.
The other half of segregation is a written top-up rule, decided while you are calm. Mine is boring on purpose: the account gets refilled from a fixed monthly amount, the same way a subscription gets paid, and it never gets refilled in response to a loss. If the account goes to zero in the first week of the month, it stays at zero until the next scheduled contribution. Writing this down feels like a formality, but the written part carries most of the weight, because the spiral that genuinely ruins people is the reload. Lose the account, transfer more the same night to win it back, lose that faster because now you are oversized and angry, and repeat until the money going in is money that had a job, which is how people end up trading their rent. Every step of that spiral requires a fresh funding decision made in the heat of a loss, and a rule you wrote on a quiet Sunday removes the decision entirely.
Size the account for the worst month, not the best one
Passing the risk capital test tells you which money is eligible. It does not tell you how much of it to deploy, and it is entirely possible to fund an account with clean risk capital that is still too big for you, because survivable has a financial component and an emotional one, and they rarely fail at the same size.
Financially, assume the account will at some point be down by half. Historically, even competent discretionary traders sit through drawdowns of a third to a half of their equity, and beginners typically do worse because their position sizing is still calibrating. If a 50 percent drawdown in the account would matter to your broader finances, the account is too big, whatever label the money carries.
The emotional ceiling is lower and harder to see. Somewhere there is a dollar figure of open loss that changes how you trade. Below it you follow your rules, take the stop, and log the trade. Above it you start widening stops, averaging into losers, and checking the position at three in the morning. You want the account sized so a realistic worst case drawdown stays under that figure, and the only honest way to find it is to start smaller than feels necessary and watch for the moment your behavior changes. A reasonable starting point is an account small enough that being down half of it registers as annoying rather than consequential. For most people starting out, that lands somewhere in the low single digit percentages of liquid savings, which sounds insultingly small right up until the first deep drawdown, when it turns out to be the reason you are still trading.
The funding policy, written down
Put all of this in one document before you fund anything. It fits on half a page and needs five lines.
- Source. Name the one account trading money comes from, and state that no other source is eligible, ever, including credit.
- Initial size. The starting balance, sized so a 50 percent drawdown is financially irrelevant and emotionally tolerable.
- Top-ups. A fixed amount on a fixed date, never accelerated and never increased after a loss.
- The zero rule. If the account blows up, it waits for the next scheduled contribution, and you write a short review of what went wrong before that money goes in.
- Withdrawals. A ceiling above which profits get skimmed back to savings, so a good run raises your savings instead of your position sizes.
A funding policy does nothing for your trade selection. It just makes sure the person deciding how much to risk is always the calm one holding a document, instead of the one who took a hit an hour ago and wants it back tonight. I know traders with mediocre win rates who have survived for years on little more than this, and I know sharper ones who are out of the game because their funding policy was a mood. If you only do one thing after reading this, open the second account and set up the standing monthly transfer. The document takes twenty minutes, and you only have to write it once.