For an asset stored in Advisors Assistant, this is the number of shares multiplied by the closing price on a particular date.
For purposes of rate of return calculations, when an asset is purchased on or after the beginning date of the calculation period, the Beginning Market Value is the price paid multiplied by the number of shares. The closing price is not used when the initial purchase is during the measurement period.
For Selection Reports, Market Value is the closing value on the Calculate To Date shown on the Selection Criteria Investment Details Tab.