I think it merits serious consideration for more widespread adoption, irrespective of the accounting and tax treatment such reserves might attract. One key feature of such reserves is that they should be useable. That is, the markets and analysts need to accept that using such reserves to absorb write-offs when losses are high is the natural counterpart of building them up when losses are cyclically low. It is not a sign of  BIS Review 145/2008  5  weakness or of inadequate capitalisation, but of prudent management of the cyclical pattern of losses. From the point of view of market acceptability, separating cyclical reserves from more structural capital requirements seems a valuable idea. The second scheme I want to promote is growth-related capital requirements. Losses tend to be lower in the early stages of a loan’s life than when it is fully seasoned because borrowers are more certain of their own and the economy’s near-term prospects. A loan book which is growing more rapidly than average will be weighted towards such unseasoned loans, and so will appear to be performing better than a balanced portfolio of loans of different vintages. In addition, rapid growth of lending tends itself to be associated with taking on poor business – even if that is not obvious at the time it is written. Typically, rapid growth can only be achieved by drawing in marginal borrowers to the market. That is true of the banking sector as a whole.
The flow of funds into the US was re-exported to the advanced economies, especially through the growing securitisation markets, and helped finance the rapid increases in house prices in the UK (Chart 2) and many other countries. And that internationalisation of markets was reflected also in the build up in our banks of portfolios of AAA-rated securities which offered a slightly better yield than traditional bonds and many of which were based on sub-prime assets. BIS Review 145/2008  1  So when losses emerged in sub-prime market, they not only hit US banks but ricocheted through the international financial system. Much of the commentary has focused on the structured credit losses in banks’ trading books and treasuries and they have certainly been large. But equally as important was the impact on the liability side of balance sheets. Banks had not only expanded their balance sheets too far, they had in the process become reliant on wholesale funding markets which had not been tested in a downturn. In the UK, the gap between customer lending and deposits moved from zero at the turn of the century to over £ billion in 2008 H1 (Chart 3). That proved a structural weakness when investors realised that the AAA label concealed substantial and uncertain risks and withdrew from the securitisation markets. Just as the origins of the crisis lay in global imbalances its effects are also global.