[Pharaoh]

I can think of several kinds of people who could lose 50% or more of an account on a single trade.

1. Someone who doesn't understand their broker platform and enters too large of a trade.

2. The same kind of person who bets his monthly mortgage on a hunch. Compulsive gamblers should not trade forex.

3. Someone who trades with no stoploss (not even an emergency stoploss). "Hey, the market never moves over 100 pips in 2 minutes when there's no news release scheduled, right?"

4. The new trader who has no clue about risk management and can only think about how much profit the trade will make, especially if he's just bought some over-hyped "no lose" system.

I'm sure there are more.