The 11th district cost of funds index reversed course after decreasing for three consecutive months.
The COFI, as it is widely known, rose to 1.758% in June from the previous month's record low of 1.708%, the Federal Home Loan Bank of San Francisco reported. The figure a year ago was 2.113%.
The average total funds used in the calculation of the index was reportedly $434.4 billion in June, about 4% above May's total.
The index is announced about 30 days following the end of each month, and reflects interest expenses during a given month by all member savings institutions headquartered in Arizona, California and Nevada.
The 1-year Treasury-indexed ARM was 4.17% last week, according to Freddie Mac. The 1-year Treasury competes with the COFI as the index for ARMs -- which currently account for one-third of all mortgage applications.