I have no knowledge of finance whatsoever, except buy high sell low. Or is it the other way around?

But you're right, it's sometimes best to admit defeat rather than lie and bluster your way through something.

I was once teaching in Morocco and was asked a difficult question about English grammar by a team of very clever engineers.

I pretended to know, but I didn't. I half knew. They knew I didn't know, but I continued anyway. It destroyed their confidence in me.

I should have said, I don't know, I'll tell you tomorrow.