One of Markel's (NYSE:MKL) biggest equity stakes is Berkshire Hathaway (NYSE:BRK.B) – is that bad for diversification?

In this segment from The Motley Fool's everything-financials show, Where the Money Is, banking analysts David Hanson and Matt Koppenheffer take a question from their mailbag about Markel's portfolio.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.