Complex sentence: A Risk measure is used to determine the amount of cash kept in reserve in order make the risks acceptable taken by financial institutions, such as banks and insurance companies, acceptable to the regulator.
Split into simpler sentences: A Risk measure is used to determine the amount of an asset or set of assets (traditionally currency) to be kept in reserve. The purpose of this reserve is to make the risks taken by financial institutions, such as banks and insurance companies, acceptable to the regulator.