Their killing and the exchange of gunfire that led to the shooter's death occurred in "a relatively short duration of time, " added Petucci, and physically all within a 1.5-mile radius.

CNN: 4 dead, including shooter, in central Pennsylvania

Also, mortgages have a duration (a calculation of the time it takes to get paid back) that is a variable, hypothetical duration that varies with prepayment speeds, so a short duration mortgage portfolio is not protection against a sudden increase in interest rates, because if interest rates rise the duration will rise which hurts the value of the bond.

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Another popular strategy in a rising rate environment is to keep the duration of your fixed income investments short.

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