COST OF SAVINGS INDEX - COSI INDEX

Metric used to determine rate adjustments on adjustable-rate mortgages (ARMs). The index is comprised of weighted-average of the interest rates placed on the deposit accounts of the Golden West Financial Corporation (GDW)’s depository institution subsidiaries. The corporation calculates the COSI on the last day of every calendar month and announces it on or nearest the last business day before the 15th day of the following month.