The earnings rate for Series I Savings Bonds is a combination of a fixed rate, which applies for the life of the bond, and the semiannual inflation rate.

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They resemble bonds in that their dividend rate is typically fixed, much like a bond coupon.

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Still, floating-rate bond funds may be the best fixed-income deal available in an environment of rising short-term interest rates.

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Typically, buyers of perpetual bonds receive a fixed rate of return but expect the issuer to redeem the bond after several years.

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For one thing, it is hard to know how much companies have in fact lengthened the maturity of their debts because the interest-rate swap market allows them to swap those fixed bond payments into cheaper floating debt, a popular strategy in the investment-grade market.

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Another reason demand for the long bond has been so voracious is that a lot of investment banks still use them to hedge their corporate-bond positions and interest-rate swaps (between fixed- and floating-rate obligations).

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With bond yields rising since the Fed announced QE2, 30-year fixed rate mortgage interest rates went up to their highest level since the week of September 30 to 4.46%.

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The fact that early bonds had no fixed maturity date ensured that any change in interest rate was fully reflected in the capital value of the bond.

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Unlike traditional bonds, SIBs do not have a fixed rate of return as financial return depends on the achievement of specific social outcomes set at the start of the bond issue.

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