The US government has then traded a fixed rate of 0.57 for a bet on the variable rate of US T-Bills over the the next 10 years.

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And I also think another variable that we haven't thought about is the early voting.

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For instance, Apple offers customers up to 18 months interest-free on purchases on a card from Barclaycard US. But if you don't pay off that specific purchase in the interest-free period, you'll face a variable annual percentage rate that's currently about 23%, according to the Apple website.

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But that doesn't always make it a smart investment, particularly when the stiff fees in some products, such as variable annuities, are considered.

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