Most Britons, for instance, still have variable-rate mortgages, although the proportion with fixed-rate home loans is rising (thanks, in part, to lower inflation).

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For instance, the two cards offered through Banana Republic have variable rates recently at 24% and 25%, higher than the recent average rate of 15% on all variable-rate cards.

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Trading Direct, for instance, lends investors who are willing to assume a heavy debt load at a variable rate of 1.25 percent.

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