Gain
In financial terms the amount by which something increases in value is called a 'Gain'.
The principal use of the term in the field of taxation is when there is an increase in the value of an asset resulting in a capital gain (see 'Capital Gains Tax').
The term can be prefixed with a descriptive word determining the stage of gain and its relevance to the final result. Examples of this are 'principal gain', 'net gain', 'final gain' and 'taxable gain'.