39.3 Aggregation Action Operations

The following are the default aggregation action operations:

• Average: Calculates the average value of an attribute for all instruments in the pool.
• Weighted Average: Calculates the average weighted value for an attribute by the current balance.

Examples of attributes for which you may want to calculate the weighted average are interest rate fields: interest rates, cap rates, floor rates, and interest rate margins for floating rates. Other possibilities include the remaining term, original term, loan to value, and so forth.

• Min, Max (minimum, maximum): Select one of these operators to populate the pool with the minimum or maximum value of a given attribute for all the instruments that are part of the pool.
• Median: Applies the Median Date value for all date values in the pool.
• Sum (The sum action calculates the total sum value for a numeric attribute.

The most common attributes that you want to calculate the sum for are the balance and payment amount fields. By calculating the total of the balance and payment amounts, the total of all pool balances should reconcile to and represent the totals of all instruments that are in the portfolio.

• Default: Applies a specified default value.