major concepts of my money management: max loss and ROA
Basically, after excluding a lot of details, the two major rules of my systems' money management are these:
1) maximum loss:
systems are allowed to trade contracts according to how much their maximum loss is.
For example, let's say that I have 10k and that a system's maximum loss is 500. If I set the maximum loss allowed to 20%, that system will be allowed to trade as many contracts as would cause a maximum loss of 2000 dollars, so 4 contracts.
If another system has a maximum loss of 2000, then, with 10k, it will be allowed to trade only 1 contract. The second contract will be allowed at 20k.
2) Return On Account:
I measure the quality of systems by their Return On Account and allocate capital accordingly. By my rules, Return is the profit made during forward-testing. Account, which as measured by TradeStation means the drawdown, by my rules is the maximum of whichever has the highest drawdown between forward-testing and back-testing (over the past 10 years). This method tells me exactly how good a system is.
Say a system lost during its worst drawdown as much as 10k and has a forward-testing profit of 5k. This to me is a ratio of 50% of Return On Account: a Return of 5k divided by an Account needed of 10k, to withstand the maximum drawdown. Forget the fact that systems require different margins, which also should affect ROA, but which is included with other rules. So we got a system with a ratio of 50%.
Then say we have a system that has a maximum drawdown of 10k like the previous example, but a Return of 20k. To me this system is 4 times as good, and its ratio will be 20k divided by 10k, which is 200%.
Accordingly, I will allocate contracts as follows. First of all, I rate all these ratios on a scale, with the highest being given a rating of 100%, and the others less, dividing them by the highest ratio. In this case I get 100% for the second example, and 50/200=25% for the first example. Accordingly, they will be allocated 100% of capital and only 25% of capital, which will then depend on how much capital the best system is given. If I'm desperate for capital I could even give all capital to every system, whenever I get a signal, but this will cause me to miss a lot of signals, especially if the best system is trading.
Now these two parameters, the max loss and the ROA combine like this: systems will be allowed to trade according to how good they are and to how big their maximum loss is, which makes a lot of sense.
Some potential scenarios:
One system could be awesome, with a great return and a small drawdown, but if its maximum loss is huge, then I might not be able to trade it.
Another system could have very small drawdown, very small maximum loss, but still not much return: take for example a system that makes 100 and loses 100 once a day. This will have no warning signs, but without a decent return, it will also not get traded.
Now let's take the case of a system with a good return of 10k, but with a drawdown much bigger than its return, even if it were made by small losses. Such a system won't get traded either, because of the disproportion between its drawdown and its gain.
So the only absolute value is the maximum loss, whereas the drawdown and the gain and relative to one another. A small gain with no drawdown gives a good ratio, potentially better than any other system (e.g.: zero drawdown, and 1 dollar gain) and somewhat misleading. That is why all systems are given the drawdown according to back-testing: this way even with a small and lucky forward-testing they don't have unrealistic ROA ratios due to no losses during the last 7 months of forward-testing.
All these rules have been developed during the last few months and have been the same for the past 3 months or so. Even today I reviewed them looking for problems, but I kept them exactly the same, because they are perfect from every point of view.