All this would be similar to a homeowner forsaking a 4.5% fixed-rate 30-year mortgage for a variable-rate mortgage of nearly 5%.

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About half of mortgage borrowers have variable-rate loans and are therefore generally benefiting from the reduced cost of servicing their debt.

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The same is true of the assumption that the mortgage repayment will rise (it could be a longer-term fixed rate for example), or by how much - we have used the Standard Variable Rate (SVR), but the borrower may be using a mortgage which charges a different interest margin.

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