This has strengthened banks' earnings situation in areas outside of the real estate business, thereby enabling banks affected by the credit crisis to compensate part of their losses. If the  2  Benchmark index of credit default swaps (CDS) on US securities covered by commercial mortgage-backed securities (commercial MBS), 2-2006 vintage with AAA rating. Source: Markit. 3  "Delinquency Rate on Credit Card Loans (All Commercial Banks)", USA. Source: Federal Reserve. BIS Review 150/2007  3  general economic environment were to deteriorate, this previous important source of stability would be adversely affected. Nevertheless, we must stress that the banks are still operating in a stable real economic environment, and that economic data from Europe, Latin America and Asia continue to provide evidence of robust growth momentum. What can be learned from the current crisis? How can we ensure that the kind of market turmoil we are experiencing at present can be avoided in the future, or at least does not occur on this kind of scale? And how can we make sure that the banking sector will be in a position to emerge from comparable or even worse disruptions unscathed? Once again we need to stress that definitive conclusions cannot yet be drawn because the current crisis has not yet been overcome. However, as initial provisional lessons from the crisis, the following points seem particularly important to me. First, banks need to improve their transparency on a sustainable basis.
Specialised features of these assets affect both how easily they can be sold or restructured, and how attractive they may be to other market participants. Bespoke and sometimes innovative features of some of these assets may increase uncertainty around this. Since Solvency II was implemented, the range of asset types in MA portfolios has expanded substantially, including increased investments in a wide variety of illiquid loans and other forms of private credit. We estimate that annuity firms’ holdings of assets other than corporate or UK government debt has grown, from around 15% of assets backing annuities at the end of 2014, to around 45% of MA portfolios at the end of 2020[3]. The PRA is attuned to the merits of these investments, both in terms of risk diversification for firms, and for the real economy of the UK. It is in that spirit that the PRA has worked with the BPA sector over the last six years or so to  Page 6  support the safe growth of more diverse MA portfolios than was the case when the MA requirements were drafted. Indeed, there is now a very wide range of assets in firms’ MA portfolios as shown in Chart 3. However, all assets are not equal in terms of the MA they generate with, for example, Chart 4 indicates that current investments in student accommodation benefit from almost double the MA of current infrastructure holdings.