How much exposure to US stocks is too much?

Professional investors are slowly waking up to the realisation that quite by accident they have become enormously overexposed to the US, and they are not sure of the way back Professional investors are slowly waking up to the realisation that, quite by accident, they have become enormously overexposed to the US, and they're not sure of the way back. For as long as anyone who manages money for a living has been in this game US stocks have been a natural destination for foreign investors, whereas loading up on the UK, Europe, Japan or emerging markets has always been perceived…