The financial crisis has heightened the awareness of the risk of a sudden shortage of foreign currencies. Governments and central banks are looking for ways to obtain "liquidity assurance", ie the assurance of having access to international liquidity if they need it. This article discusses how such assurance might be provided, whether by multilateral means, such as reserve pooling or structures such as the IMF; by bilateral means, such as swap arrangements; or unilaterally, by building up foreign exchange reserves. All of the possible solutions have advantages and disadvantages, and a diversity of approaches therefore seems likely. If international arrangements are deemed to be inadequate, unilateral actions will continue.