ultimatepick
The guy that wrote the article may be confusing "leverage" with money and/or risk management. The leverage in an account deals with how much capital you're forced to set aside as a margin requirement for a single trade.
If you're at 200:1 leverage, you're then required to set aside $500 for margin per lot ($50 for a mini). At 4:1 leverage, you'd be required to set aside $2500 per lot (or $250 for a mini).
As for money management, that's pretty well determined by where you set your stop loss. A lot of professional investors feel that risking 5% of your portfolio on one trade is fairly aggressive. Some put a maximum of 1% to 2%. Putting 10% would probably be OK...but the person would need to realize that they'll likely take huge drawdowns on their account when they take a loss. However, if the system and rules you're trading with get you a pretty high expectancy ratio (average expected portfolio gain when gains and losses are averaged together), then 10% might be OK.
Most professionals will first ask "how much do I stand to lose if this trade goes bad"? This is determined by support/resistance levels. The second question is then..."now that I know how much I stand to lose...does the potential reward greatly outweigh the risk"? If so, then you already know where to set the stop loss. Some folks with smaller accounts argue against stop losses. However, you'll find that once you have a significant amount of money in an account, you tend to get a little skittish...and will usually want to set a stop loss to protect your capital because your ENTIRE ACCOUNT is at risk if you don't set it.
Once you've determined your risk to reward ratio, you will then usually have a set rule for amount risked. If you've decided to risk 4% per trade max, you simply look at the stop loss, and also 4% of account balance, and divide the 4% number by the stop loss. This gives you the number of lots to trade.
So, to answer your question, it seemed that the guy that wrote the article was suggesting that you put no more than 4% of your account at risk per trade. WHile he phrased it kind of strangely, I tend to agree with him as a general rule. However, I believe the tendency for traders when first starting is to bet the bank on one trade. If that's the case, they're either going to be very happy, very sad...or very happy at first and then very sad later. LOL
Long answer to a short question. I hope this helps.
