Simon Evan-Cook: What's the biggest risk you're taking?

What's the biggest risk you're currently taking? This is a question I often ask prospective fund managers. It's meant to refer to risks in their fund, but if I get the odd tale about cliff diving in Brazil then that's no bad thing. What I really mean is: if there's one thing that could derail your current portfolio, what is it? This can be revealing in different ways. Firstly, do they have an answer? Many don't. You can split this mob into two groups, neither of which are good: Some will resort to waffle, suggesting they haven't thought about their portfolio in enough depth. The secon...