资金管理的一个关键组成部分就是5%原则。其实就是，永远不要在同一时间把超过交易账户总资金5%的资金放到风险上。其原理是当我们获得损失的时候（任何人都会有损失出现，这是毋庸置疑的），这些损失将会比较小并且容易处理，反之则不然。
然而在很多时候，这条规则被错误的解释为每笔交易投入5%的资金，这个解释是不准确的。
这里的5%是指账户总资产的风险比例，不是指在单一交易中投入的交易资金量。因此，如果你有一单交易在进行中，5%是投入的最高保证金风险。如果你有两单，五单或者十单交易在进行，这些交易共同止损的最高金额也是5%。
设想一下，如果这个规则是指每单交易的最高保证金风险都是5%，一个交易员就可以在这个规则下有五单最高风险是5%的交易。那么什么能阻止一个交易员开十单并且每单的最高风险都是5%呢?
此规则必须有一部分能阻止交易员过度杠杆借贷且保证任何时候都是5%风险。另外，就像我们从前面那个每单交易5%的例子中看到的，有五单这样的交易员就有25%的账户金额处于风险之中，而有十单这样交易的交易员的总账户金额的50%就在风险中。
很明显，这都不是谨慎的交易员愿意看到的情况。
Clarifying the 5% Money Management Rule
One of the key components of Money Management is the 5% rule. That is, never put more than 5% of the trading account at risk at any one time. The rationale behind this is that when we have losses (and we WILL have losses, make no mistake about that) they will be small and manageable as opposed to large and catastrophic.
Oftentimes however, this rule is erroneously interpreted as meaning 5% per trade. This is not accurate.
The 5% rule pertains to the TOTAL amount of the account balance at risk at any one time...NOT on any individual trade. So, if you have one trade open, 5% is the maximum allowable risk. If you have two trades open or five trades open or ten trades open, the maximum that could be lost if the stops on all of the trades triggered at the same time is 5%.
Think of it this way, if the rule were 5% pertrade, a trader could open five trades risking 5% on each trade and still be within the rules. What would prevent a trader from opening up ten trades and only risking 5% on each one?
There has to be something that prevents the trader from over leveraging their account and that something is the “5% risk at any one time” part of the rule. Otherwise, as you can see from the previous 5% per trade example, the trader with five trades with 5% account risk on each one would have 25% of their account at risk and the trader with ten trades would have had 50% of their account at risk.
Clearly, neither of those would be a situation in which a prudent trader would want to find themselves.
本文翻译由兄弟财经提供
文章来源：http://www.forexcycle.com/forex-trading/35624-clarifying-the-5-money-management-rule.html