Limitations on loan-to-value and loan-to-income ratios, which are applied in Norway, are examples of rules that can have a stabilising effect. Minimum capital requirements for financial institutions and liquidity and funding structure requirements are other examples of rules that will make high credit growth more expensive for financial institutions, and thereby for customers. Rules to ensure that shareholders and creditors bear the cost if banks suffer substantial losses or have to be wound up will have a similar effect. Financial vulnerability can build up more quickly in periods of expansion, partly because financial institutions then have a stronger inclination to take risk. This implies that regulations should be countercyclical, having the strongest effect when the risk of a buildup of imbalances is greatest. It is important that the rules function as automatic stabilisers in the economy. Discretionary use of instruments is considerably more demanding. But it may nevertheless be advisable to introduce such instruments, such as capital requirements that vary over time with the rise in debt and asset prices. The Basel Committee, which assesses new rules for financial institutions and which includes members from major countries, has proposed the introduction of a time-varying capital buffer requirement over and above the minimum capital requirement. Financial corporations with a capital buffer judged to be insufficient would be subject to restrictions on dividends and other payments to shareholders and employees.
Much of this “banking glut” 4 can be traced to the advanced economies: for example, around half of the gross inflows into the United States just before the crisis came from European institutions, rather than emerging economies. 5  3  See Borio and Disyatat (2011), Cecchetti (2011) and Tucker (2012) for more on this issue. 4  See Shin (2012). 5  See Borio and Disyatat (2011). BIS central bankers’ speeches  3  Now global capital flows of this nature can be valuable. They help to oil the wheels of the international financial system, allowing saving to flow to where it can be most effectively used. They allow banks to diversify across national boundaries, reducing their susceptibility to idiosyncratic domestic shocks. And they increase the degree of competition within the domestic banking market. But by increasing the linkages between financial systems, they can also increase systemic vulnerabilities. In this case, banks became dependent on shortterm funding from overseas, rather than their traditional domestic deposit base. When investors re-trenched, that funding dried up and banks struggled to find viable alternative sources of funding. Ensuring gross capital flows are not excessive is just as important as avoiding excessive net capital flows. Moving to a sustainable equilibrium requires a narrowing in the international payments imbalances. And we have indeed seen such a narrowing since the start of the crisis.