The “Brexit” vote in the United Kingdom last week helped significantly reduce interest rates on new jumbo mortgages. Looking forward, it’s not clear if rates will remain low, which would boost refinance volume, or if banks will make further adjustments. The Brexit vote prompted investors to increase their holdings of 10-year Treasury notes, pushing down yields. Interest rates on mortgages tend to follow trends in the 10-year Treasury, though rates on jumbo mortgages can be ...