"The Certificate of Deposit Index (CODI) is the 12 month average* of the monthly average yields on the nationally published 3-Month Certificate of Deposit rates. 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." The history of the CODI follows: Aug 2007 5.214 4.47 5.3333 Sep 2007 5.251 4.14 5.3433 Oct 2007 5.278 4.10 5.3225 Nov 2007 5.296 3.50 5.2933 Dec 2007 5.305 3.26 5.2683 Jan 2008 5.300 2.71 5.1450 Feb 2008 5.274 2.05 4.9575 Mar 2008 5.228 1.54 4.7483 Apr 2008 5.163 1.74 4.5433 May 2008 5.078 2.05 4.3225 Jun 2008 4.976 2.42 4.1083 Jul 2008 4.857 2.28 3.897