Bolton reveals three investment mistakes he has made repeatedly:
- poor management
- ineffective business models
- weak balance sheets - his number one factor
IIRC, Pabrai did an investigation into Buffett's worst mistakes. Weak balance sheets featured highly.
Contrariwise, Greenblatt seems to have made a lot of money in mundane businesses which had a lot of debt which was gradually cleared up. I have also been reading through BB posts where people have invested in some very sticky situations, and seem to do quite well at it. It looks to be a high stakes game where picking exactly the right spots, and timing, are crucial.