Structural risks refer to fault-lines within the financial system, such as high concentrations of risk, complex interconnections, promises made that cannot necessarily be honoured, and uninsurable – or tail – risks. These risks can trigger sharp reversals in financial conditions, or amplify cyclical risks when they crystallise.6 As with cyclical risks, macro-prudential policy looks to build resilience to these risks, as well as eliminating fault-lines where appropriate. The cost-benefit calculus In seeking to fill these two gaps, it is important to acknowledge that there are two sides to the ledger – that a build-up in financial stability risk is often accompanied by higher growth. When the financial system under-prices risks, households, companies and the economy at large may appear to benefit. As asset prices rise, perceptions of wealth become inflated and risks appear smaller. Households and companies feel more comfortable taking on debt, banks and investors feel more comfortable lending to them. We can consume more, invest more, grow the economy more and feel more prosperous. The problem is that it cannot last. We cannot continue consuming more than we ever hope to earn; we cannot invest more than we ever intend to save; risks cannot be under-priced forever. This time it probably isn’t different. And when it all goes into reverse, when risks are found to be under-priced and not well-dispersed, when shocks arise and are amplified by the financial system, the cost in terms of lost growth can far outweigh the benefit of higher growth enjoyed while the risks were building.
13 In Q1 2022 Financial Stability in Focus Bank of England sets out the role of cryptoassets and DeFi in the  financial system and identified potential risks associated with them. 14 Breeden (2022) talks about the economy’s transition to net-zero, and the role central banks can play to support  it. 7/7  BIS central bankers' speeches