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.

BREAKING DOWN '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 TERMS
  1. Current Index Value

    The most recently published value of an underlying interest rate ...
  2. Mortgage Index

    The benchmark interest rate an adjustable-rate mortgage's fully ...
  3. ARM Index

    The benchmark interest rate to which an adjustable rate mortgage ...
  4. 5-6 Hybrid Adjustable-Rate Mortgage ...

    An adjustable-rate mortgage with an initial five year fixed interest ...
  5. Fully Indexed Interest Rate

    The interest rate on an adjustable-rate loan that is calculated ...
  6. Teaser Rate

    An initial rate on an adjustable-rate mortgage (ARM). This rate ...
Related Articles
  1. Investing

    Money-Losing Cosi Has Fresh Food, Needs Fresh PR

    While its rivals like Panera Bread (NASDAQ: PNRA) have been thriving, Cosi (NASDAQ: COSI) has struggled. Though the chain offers similar fare to Panera, it has not caught the public's attention ...
  2. Personal Finance

    The Best Candidate For an Adjustable Rate Mortgage

    Adjustable-rate mortgages aren't for everyone, but they make sense if you are a short-term homeowner or can pay off the loan before it readjusts.
  3. Personal Finance

    Mortgages: Fixed-Rate Versus Adjustable-Rate

    Both of these have advantages and disadvantages depending on your financial needs and prospects.
  4. Personal Finance

    This ARM Has Teeth

    Find out how to avoid getting bitten when your mortgage rate resets.
  5. Investing

    Subprime Is Often Subpar

    Proceed with caution when considering these short-term, high-interest mortgages.
  6. Personal Finance

    5 Secrets You Didn't Know About Mortgages

    Being savvy about the ins and outs of mortgages can mean big savings in the long term.
  7. Personal Finance

    Fixed Or Variable-Rate Mortgage: Which Is Better Right Now?

    Find out the benefits of fixed- and variable-rate mortgages, and learn which option is best for you.
  8. Personal Finance

    Score a Cheap Mortgage, Here’s How

    Hidden costs can create what looks like a good deal. Find out how to find the best mortgage possible.
  9. Personal Finance

    Make A Risk-Based Mortgage Decision

    Find out how to choose which mortgage style is right for you.
  10. Insights

    What to Expect From Mortgage Rates in 2016

    Understand the factors that influence the direction of mortgage rates, and use this information to project what will happen with rates in 2016.
RELATED FAQS
  1. What are the Federal Reserve's guidelines on demand deposit accounts?

    Read about some of the Federal Reserve's requirements and guidelines regarding the treatment, safeguarding and processing ... Read Answer >>
  2. Is an adjustable rate mortgage (ARM) safe?

    Learn why an adjustable rate mortgage (ARM) can be a safe option as long as the borrower is familiar with the underlying ... Read Answer >>
  3. What are the pros and cons of a simple-interest mortgage?

    Learn the difference between a simple interest mortgage and a standard mortgage, along with their relative advantages and ... Read Answer >>
  4. Is it possible to invest in an index?

    First, let's review the definition of an index. An index is essentially an imaginary portfolio of securities representing ... Read Answer >>
Trading Center