What lot size should my "Conservative FX Manager" use on a $10K account. He does about 8% pm with about 10 to 15 trades pm.
IF I make the assumption that this is what he always does:
This is less than 1 trade per day... on the low side, less than 1 trade every 2 days. If he's gonna be trading like this, then I would suggest his PIP target should be higher (if he's targeting and achieving 8% monthly), and therefore his lot sizes should be much smaller. Does he trade for an hour every other day, then call it quits? I don't endorse this "method" for lots of reasons. If so, he's working less often for less time and tries to make up for his off time with super aggressive trading. This can only end in disaster, eventually. My take on it is that he should do one of the following:
1. At MOST he should be trading 1 lot trade sizes (100k lots, one open at any given time) with tight stop losses and very modest take profit targets. If he does this, then he should commit to more time and open and close many more high-probability trades per day. Even with this strategy, I prefer to use smaller contract sizes and leave open the option of price-cost averaging strategy if the market starts to go against me but indicators hold.
2. If he's gonna let the trades run for a day or more, which it seems you are saying he does, then his lot sizes should be MUCH smaller... like 0.1 - 0.5, and his pip target needs to be larger, too.
How much was lost?
To be honest, I feel a little uncomfortable evaluating another trader on such little information. Let's just say that I am offering general principals from my own experience and within my own methodology and criticizing a hypothetical alternative.