An advertisement portfolio model reduces risk in an advertisement transaction for an individual advertisement product. First, a relational expression is used to determine a comprehensive advertisement risk management index for statistically representing a maximum unexpected loss amount to which the advertisement product is subject at a certain probability during the advertising campaign period. Second, a plurality of correlation coefficient data of the advertisement product are calculated from the observational data of the advertisement product. Third, an optimal combination of the advertisement products is determined in order to analyze at least either one of an effect, an efficiency or a risk of the advertisement product based on the relational expression for determining the comprehensive advertisement risk management index and the plurality of correlation coefficient data or the observational data which has taken the correlation into account indirectly, such that a sponsor can determine an optimal combination of the advertisement products.