* The CODI Index is calculated by Mortgage-X using the H.15 Federal Reserve Statistical Release data and is usually published on our website on the first Monday of the following month. Mortgage-X calculates the average by adding the 12 most recently published monthly yields together, dividing the result by 12 and rounding this result to the nearest 10,000th of one percentage point. Information on monthly yields on 3-month certificates of deposit (secondary market) is published by the Federal Reserve Board.

Because this index is an annual average, it is more steady than CMT and CD indexes which are very volatile and generally considered to react quickly to change in the market. The CODI and MTA indexes generally fluctuate slightly more than the 11th District COFI, although their movements track each other very closely (as illustrated on our historical graph). The MTA, COFI and CODI-indexed ARMs work much the same way.