COleCurrency does not have a base class.
A COleCurrency object encapsulates the CURRENCY data type of OLE automation. CURRENCY is implemented as an 8-byte, two's-complement integer value scaled by 10,000. This gives a fixed-point number with 15 digits to the left of the decimal point and 4 digits to the right. The CURRENCY data type is extremely useful for calculations involving money, or for any fixed-point calculation where accuracy is important. It is one of the possible types for the VARIANT data type of OLE automation.
COleCurrency also implements some basic arithmetic operations for this fixed-point type. The supported operations have been selected to control the rounding errors which occur during fixed-point calculations.