CoreLogic reviews the universe of active loans for clues to future refinance activity:
Because a refinance isn’t free, a simple rule of thumb is to add 100 basis points to the current market mortgage rate as the rate at which borrowers would have an incentive to refinance…Therefore the typical borrower would need to hold a mortgage rate of 4.57 percent or higher to make refinancing a money-saving option. According to the chart, most borrowers hold mortgages with rates up to 4.50 percent, with 62 percent of mortgages and 72 percent of UPB in this range. There are an additional 14 percent of borrowers and 13 percent of UPB with mortgage rates between 4.5 and 5.0 percent, and if mortgage rates were to increase by 50 basis points in 2016, these borrowers (about 5.5 million) will generally find refinancing unappealing.
A drop in refinancing does not mean that borrowers won’t be taking out new loans. Even though at least 62 percent of borrowers most likely don’t want to refinance out of their low mortgage rates, they still might want to tap into their equity to pay for remodeling, education expenses, or debt consolidation.
Read more at Corelogic: How much is left to refinance