Hi landlord
I have shares in CRH. Some people think that as it's denominated in euro I am only exposed to the euro.
In fact, CRH earns its profits in euro, dollars, sterling and a host of other currencies. So I get natural diversification that way.
Likewise, Berkshire's investee companies might be all based in America, but if they export a good amount of their output, then you have exposure to other currencies.
Brendan
People think they get diversification this way but they more than often don't because the company will themselves hedge the FX exposure of foreign earnings as much as possible. I have no idea what CRH's hedging policy is but it might be worth while checking it out to see.