Rationale of Central Banks Buying Gold - Mises.org

Holding gold does not eliminate the possibility of negative equity for the central bank (indeed, it might even increase the odds). But given the recent past it makes for an attractive option. As countries demonstrate their difficulties in getting their debts and deficits in order and thus improving their solvency outlooks, the value of their debt becomes questionable as well.

While holding any real asset serves no direct use for a central bank, it does act as an insurance policy of sorts. The solvency of a central bank holding government debt is subordinate to the solvency of the countries whose debt it holds. For a central bank worried about the value of its assets, diversification of its assets into gold makes for a rational alternative.

Read rest of the article here.