Diversify to Avoid Being Burned by Underhanded Executives

While we’ve generally avoided being hurt by underhanded executives, that risk is always there and it’s far more pronounced if you’re running a concentrated global portfolio. A second reason we’re more diversified is because I believe a lot of our alpha comes from being in the right sets of companies rather than the right specific companies. If we get the themes right, we’ll do as well, with lower volatility, owning more names rather than fewer.
Source: http://www.valueinvestorinsight.com/