Following the first three rules will begin to help you manage risk in your trading activities. But these steps alone won't protect you from the risk that a single bad trade could wipe out your trading account if you risk too much on any one idea.

So it's important to consider the amount of risk you're accepting on each and every trade.

Rule 4: control your risk amount per trade

Suppose you open a trade on EUR/USD, setting a protective stop-loss order at 100 pips and a limit 200 pips away. Could you still blow up your account?

Yes, absolutely. If a move of 100 pips equates to 50% or more of your trading account, just that one trade could erase a significant portion of your equity if things go wrong. 

You can avoid this situation by controlling the risk amount on each individual trade setup.

Many professional traders will keep their risk amount per individual trade idea to less than 1% of their account equity. That way, if any given trade idea doesn't work out, the most they stand to lose from it will still leave them with 99% or more of their account equity intact.

So if your trading capital was CHF10,000, you'd risk no more than CHF100 per trade. That way, if you had an unlucky run of five successive losses, you'd still be left with a healthy CHF9,500 in your account.

For newer traders it's a good idea to start with smaller amounts; but at no time should you risk more than 5% on any given idea. Frankly, markets are unpredictable, and even the most carefully planned trade by the most experienced trader can go wrong.