crisis, it would be able to borrow from the IMF. However, the process of obtaining resources from the Fund is not automatic, which can cause problematic delays especially when markets are stressed. Therefore, the fund only serves as a provider of resources for longer term adjustments. Also, when the crisis is generalized, the resources of the IMF could prove insufficient. After the 2008 crisis, the members of the Fund had to approve a capital increase, since its resources were strained. Moreover, after the 1997 Asian crisis, reserves in Asian countries increased because of doubt in the IMF reserves. Also, during the 2008 crisis, the Federal Reserve instituted currency swap lines with several countries, alleviating liquidity pressures in dollars, thus reducing the need to use reserves. External trade Countries engaging in international trade, maintain reserves to ensure no interruption. A rule usually followed by central banks is to hold in reserve at least three months of imports. Also, an increase in reserves occurred when commercial openness increased (part of the process known as globalization). Reserve accumulation was faster than that which would be explained by trade, since the ratio has increased to several months of imports. Furthermore, the ratio of reserves to foreign trade is closely watched by credit risk agencies in months of imports. Financial openness The opening of a financial account of the balance of payments has been important during the last decade. Hence, financial flows such as direct investment and portfolio investment became more important. Usually financial flows are more volatile that enforce the necessity of higher reserves. Moreover, holding reserves, as a consequence of the increasing of financial flows, is known as Guidotti–Greenspan rule that states a country should hold liquid reserves equal to their foreign liabilities coming due within a year. For example, international wholesale financing relied more on Korean banks in the aftermath of the 2008 crisis, when the Korean Won depreciated strongly, because the Korean banks' ratio of short-term external debt to reserves was close to 100%, which exacerbated the perception of vulnerability. Exchange rate policy Reserve accumulation can be an instrument to interfere with the exchange rate. Since the first General Agreement on Tariffs and Trade (GATT) of 1948 to the foundation of the World Trade Organization (WTO) in 1995, the regulation of trade is a major concern for most countries throughout the world. Hence, commercial distortions such as subsidies and taxes are