Home bias
The tendency to hold mainly assets of one's own country: the familiar feels more comprehensible and therefore safer, although familiarity and risk are unrelated.
How to read the number
Part of the tilt is economically justified — spending happens in the same currency — but the domestic share usually exceeds both that justification and the country's weight in world market capitalisation.
When the metric lies
A portfolio of one country's securities shares everything with that country's economy at once: currency, rates, regulation, infrastructure. Diversifying inside it does not help against an event common to all of them.
Also known as: domestic market preference