Do you notice that only one person, only briefly answered him.
Brother, the true answer here is nobody from the respondents really know.
Your question might be more valid than you know... because on bigger ticket plays, maybe broker stops providing leverage (would make sense) - if so and when - I don't know; they could start some shady play... there could be some otherwise unknown limits.
And finally maybe at such levels the liquidity problems might begin and you might affect the market.
Your question is valid. All the respondents here want to act smart "risk that, trade steady, ..." they repeat the same anthem they heard someone else repeating, and it's okay... but I understand your question.
Unfortunately, I do NOT know anyone who has made huge money in forex.
My friend had a 2 mil account and he was making 200k and losing 200k a day in average until he blew the account completely.
Again, I don't know why... but my personal story is bigger than any story I have heard here anyone share... which gets me wondering... is here only the lowest of the low in the trading world or what am I missing?