Cost Of Savings Index - COSI Index

Dictionary Says

Definition of 'Cost Of Savings Index - COSI Index'

A popular index used for certain adjustable-rate mortgages (ARMs). The index is a weighted average of the rates of interest on the deposit accounts (sometimes called cost of savings) of the federally insured depository institution subsidiaries of Golden West Financial Corporation (GDW). These subsidiaries currently operate under the name World Savings.

GDW computes the COSI on the last day of each calendar month and announces it on or near the last business day prior to the fifteenth day of the following calendar month.
Investopedia Says

Investopedia explains 'Cost Of Savings Index - COSI Index'

The COSI index is a stable index. Historically, it is not as volatile as some other popular mortgage indexes, such as the one-month LIBOR index. It also tends to lag other mortgage indexes when it comes to adjusting to changes in interest rates.

Related Definitions

  • Adjustable-Rate Mortgage - ARM

    A type of mortgage in which the interest rate paid on the outstanding balance varies according to a specific benchmark. The initial interest rate is normally fixed for a period of time ...
    Read More »
  • Payment Option ARM

    A monthly adjusting adjustable-rate mortgage (ARM) which allows the borrower to choose between several monthly payment options: a 30 or 40-year fully amortizing payment, a 15-year fully ...
    Read More »
  • Mortgage

    A debt instrument that is secured by the collateral of specified real estate property and that the borrower is obliged to pay back with a predetermined set of payments. Mortgages are ...
    Read More »
    • London Interbank Offered Rate - LIBOR

      An interest rate at which banks can borrow funds, in marketable size, from other banks in the London interbank market. The LIBOR is fixed on a daily basis by the British Bankers' ...
      Read More »
    • Interest Rate

      The amount charged, expressed as a percentage of principal, by a lender to a borrower for the use of assets. Interest rates are typically noted on an annual basis, known as the annual ...
      Read More »
    • Weighted Average Coupon - WAC

      The weighted-average gross interest rates of the pool of mortgages that underlie a mortgage-backed security (MBS) at the time the securities were issued. A mortgage-backed security's ...
      Read More »
    • Current Index Value

      The most recently published value of an underlying interest rate that is used to calculated the current payment index of an adjustable-rate mortgage (ARM). The most commonly used indexes ...
      Read More »

Articles Of Interest

Partner Links