Hi Mike,
I will give you two answers: one for US traders, and one for non-US traders, since the CFTC has higher margin requirements for US residents.
Suppose you start with $10,000 equity in your account. Even though you have more leverage available, a recent DailyFX study into trader profitability has shown that you probably don’t want to exceed 10:1 effective leverage. That means with 10k in your account, you don’t want to trade more than 100k total across all your open positions.
If you live in the US like me, then a 100k USD/JPY position requires $2000 to be set aside as used margin. That leaves you with $8000 usable margin, or a usable margin percentage of 80% (8k divided by 10k). I try to risk no more than 2% on an individual trade, and no more than 20% in my account as a whole. That means I want my personal usable margin percentage cutoff to be about 60%. Below that, I would consider closing some positions or adding more funds to raise my usable margin.
If you live outside the US, then you can open an account with FXCM UK or FXCM Australia, where margin requirements are much less than what’s required in the US. A 100k USD/JPY position only requires $500 to be set aside as used margin. That leaves you with $9500 usable margin, or a usable margin percentage of 95% (9.5k divided by 10k). If you want your usable margin percentage cutoff to be after a 20% drawdown in your account, then that would be 75%.
So to summarize, since I have an FXCM US account, I try not to let my usable margin percentage drop below 60%. If I lived outside the US and had an account with either FXCM UK or FXCM Australia, I would try not to let my usable margin percentage drop below 75%. Again, these are just my own personal percentages. I know some more conservative traders who try not to let their usable magin percentage drop below 75% in the US or 90% in the UK and Australia.
There is actually a way to set margin alerts on your account, that can warn you when your usable margin percentage falls below a specified level. The warnings can be set to come as pop up messages on your platform or emails. To set up Margin Alerts on your charts, go to “Alerts and Trading Automation” > “New Strategy or Alert” > “MARGINALERT”.
In the “Strategy or Alert Parameters” window that pops up, you set the margin level when you want to receive warnings. If you live in the US, then you might also be interested in the post I made the other day about our new Smart Margin feature for FXCM US clients.
Jason