This post was authored by Ben Fulloon, a respected trader and subscriber to OneStepRemoved.
I developed an awesome strategy with a drawdown ratio of 13.67. Sounds amazing, right? Too bad that my trading platform overstated the results by more than double!
It’s important to learn about both your brokers and platforms limitations. Sometimes these intricacies only become apparent through time and experience. It’s so frustrating when your trading platform doesn’t function or report results as expected.
In this article I’ll point out two limitations of NinjaTrader 7, one bad limitation and one which can actually turn out surprisingly better for the trader in certain situations. However, this is more to do with the broker I’m using and not the platform itself.
NinjaTrader is definitely not the only platform that has limitations: MetaTrader, TradeStation, X-Trader, Matlab, etc. all have limitations for quantitative finance.
I’ll just be writing about NinjaTrader in this article to keep it fairly short and easy to read. I am also not intending to make out NinjaTrader as being a bad platform either. But, there are definitely some improvements that could be made to make it a lot easier and more convenient for quantitative traders to develop and trade strategies.
The first quirk relates to the broker I’m using. Specifically, it’s the day trade margins that I care about. These day trade margins end 15 minutes before the close of the session. For instance the ES (Emini S&P500) has a day trade margin of $500, which ends at 4:00pm CT that then reverts back to the full trading margin of $5060 before the session closes at 4:15pm CT. (Times stated are correct at time of Writing, The ES now closes at 4:00pm CT and the Day Trade margin ends at 3:45pm CT)
I’ll show you a screenshot of the results of a day trading strategy that I developed. This strategy trades the ES, NQ (Emini Nasdaq 100) and the YM (Emini Dow) all at the same time. The easiest way to exit on close with NinjaTrader is setting “Exit on Close” to true which will then exit on the close of the session.
According to the results the strategy makes a total of $332,771.60 with a maximum drawdown of $25,912.27 since 2008 to now. This is a drawdown ratio of 12.84. That’s oustanding!
The issue is… and you knew there’d be a problem… is that the strategy exits at 4:15pm CT. Day trading margin ends at 4:00pm CT. The strategy is therefore highly likely to get a margin call with a small account size.
It makes sense to tweak the strategy to make best use of the day trading margin. Ninjatrader offers a custom session template, which in this case I made end at 4:00pm CT. The results of the custom session template is as follows.
The exact same strategy applied to the same instruments to avoid a margin call makes $335,819.30 with a maximum drawdown of $24,560.51. This is a drawdown ratio of 13.67.
I didn’t change the strategy with the goal of improving the drawdown ratio AND the profit. But hey, I’ll take it. Finding a limitation in the platform can actually benefit you in some situations.
This strategy is based on trading 3 different instruments. The ES, the NQ and the YM. The problem is that I backtested it using an instrument list in NinjaTrader. What this means is they’re all tested separately. NinjaTrader then combines the test results for you as a total result like the results of the screenshots above.
Here’s what it looks like when you test them as an instrument list. This shows the different profits and drawdowns of the individual instruments.
Now at first glance it reads that the trader would have made $335,819.30 with a maximum drawdown of $24,560.51 if they traded all three instruments together. Don’t you agree?
The problem is that this is incorrect. NinjaTrader doesn’t actually combine the results like you’d think. The trader still would have made roughly that money. However, all the statistics aren’t quite correct.
To show this I recreated the exact same strategy however it will trade the ES, NQ and YM all at the same time instead of trading them separately like it does by default. These are the results when you program it into a multi-instrument strategy
It makes $335,915.30 which is roughly the same amount, but it has a maximum drawdown of $59,937.60 instead of the $24,560.51 it originally looked like it would be. This makes it a drawdown ratio of 5.60, which is a lot worse than the original 13.67.
If the trader decided to trade based upon the maximum drawdown of $24,560.51, they may get a nasty shock when the drawdown turns out to be twice as bad as they were expecting.
Incorrect calculations on such an important metric could jeopardize an account. You might assume that you can get away with half of the equity that’s actually required to trade the strategy. Oops?!?
The misleading statistics in NinjaTrader makes this strategy look really nice. But when the drawdown is more than double what it appeared that it would have been originally, you might get a nasty shock.
This is why it’s important to learn both your platforms and brokers limitations as early as possible. You don’t want to learn these limitations the hard way.
In a few weeks time, I’ll reveal a simple way to create multi-instrument strategies which show more accurate metrics. Stay tuned for my next article in the series.