The 11th District Cost of Funds Index took a sharp monthly downturn and fell to the lowest level on record.
COFI came in at 0.783 percent as of November, the Federal Home Loan Bank of San Francisco reported.
The latest level shattered the record set in May 2013, when the index was 0.951 percent.
COFI data is available back to July 1981.
The index was 0.963 percent in October.
In November 2012, COFI stood at 1.000 percent.
The index is calculated using interest expense at FHLB-members based in Arizona, California and Nevada. Average total funds used in November’s calculation were $32.5 billion.
COFI is the index used to determine rate and payment changes to adjustable-rate mortgages.
A more widely used index is the yield on the 10-year Treasury note, which rose to 0.13 percent at the end of November from 0.10 percent at the end of October, according to data from the Department of the Treasury.
The one-year Treasury yield closed out December 2013 at 0.13 percent.
ARM share jumped to 16.7 percent in the U.S. Mortgage Market Index report from LoanSifter and Mortgage Daily for the week ended Dec. 27 from 11.2 percent in the prior report .
