Just a single month after nearing an all-time low, the Cost of Funds Index reversed course and headed further north.
COFI, which is used as an index on some adjustable-rate mortgages, came in at 0.655 percent for the month of December.
The index rose from November, when it was 0.644 percent — near the 0.639 percent record low achieved in August 2015.
But COFI remained well below the 0.686 percent it reached in December 2014.
The index was reported Friday by the Federal Home Loan Bank of San Francisco based on interest expenses at FHLB-members based in Arizona, California and Nevada.
For the December 2015 calculation, $17.5 billion in average total funds was used.
More ARMs adjust based on the one-year Treasury yield, which the Department of the Treasury reported at 0.65 percent as of the end of December,
soaring from 0.51 percent at the end of November.
But by the end of January 2016, the one-year Treasury yield had tumbled to 0.47 percent.
ARM share was 8.6 percent in the U.S. Mortgage Market Index report from OpenClose and Mortgage Daily for the week ended Jan. 22.