Despite lower rates, purchase only mortgage applications were flat last week, according to the Mortgage Bankers Association via CNBC's Diana Olick:

The Brexit-induced boomlet in mortgage refinances hit new highs last week.

Lower interest rates pushed total mortgage application volume up 7.2 percent last week from the previous week, according to the Mortgage Bankers Association. The seasonally adjusted reading included an adjustment for the Fourth of July holiday.

Refinance applications were entirely behind the jump, increasing 11 percent from the previous week to the highest level in three years.

The average contract interest rate for 30-year fixed-rate mortgages with conforming loan balances ($417,000 or less) decreased to its lowest level since May 2013, 3.6 percent, from 3.66 percent, with points increasing to 0.36 from 0.32 (including the origination fee) for 80 percent loan-to-value ratio loans. For jumbo loan balances (greater than $417,000) the average rate fell to 3.61 percent from 3.67 percent.

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