Despite improvements over the years, capital regulation failed to ensure stability of the financial system in the crisis that flared in the summer of 2007. The billions of dollars of write-downs on assets related to subprime mortgages raised fears of insolvency and led to lending freezes and liquidity problems at many institutions. ; Some banks heavily reliant on short-term funding, such as Britain's Northern Rock, experienced runs. Others found themselves with a need to replenish rapidly deteriorating capital positions. All in all, the recent events underscore the need for further revisions in banking regulation.