Like fixed rates, WACs on ARMs have declined and Countrywide believes rates would have to drop 25 to 35 basis points in ARM rates to rekindle ARM refinancing to the extent seen earlier in the year. This suggests then that the MBA's Refi Index may continue to exhibit insensitivity to changes in 30-year rates unless ARM rates also move commensurately, the firm said. As a percentage of total application activity, refinancings fell to 36.8% to 37.1%. At the same time, ARM activity rose to 33.3% from 31.3% Freddie Mac reports higher mortgage rates Freddie Mac reported an increase in mortgage rates for the week ending July 30. Both 15- and 30-year fixed rate mortgage rates rose 10 basis points to 5.49% and 6.08%, respectively. This was in line with analysts' expectations. The one-year ARM was also higher at 4.17% versus 4.12% the previous week. With the increase in rates, analysts expect the Refi Index to decline in this week's report to between 1500 and 1600.