Mortgage applications slumped 12.7% for the week ending Sept. 26, slowing a streak of increased activity sparked by a fall in mortgages rates. Collapsing refinance demand led the slowdown, according to the Mortgage Bankers Association’s (MBA) Weekly Applications Survey. Mortgage rates spun higher after the Federal Reserve cut interest rates by 25 basis points on Sept. 17. Refinance activity decreased 21% while remaining 16% higher than the same week last year. The adjustable-rate mortgage (ARM) share of activity also decreased from recent highs to 8.4% of all applications last week.