At the same time, dropping markets have increased firms' liabilities. How can firms meet guaranteed policies if investment returns continue to fall? This problem did for Equitable Life last year. Now it has raised the spectre of other failures. In Britain, resiliency tests that require an insurer to be able to withstand a 25% market-fall have not helped. To protect themselves, insurers have been forced to sell stocks, sending markets even lower, so creating a vicious circle.