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Prospectus Date

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Feb. 29, 2012

Bond & Mortgage Securities Fund (Prospectus Summary): | Bond & Mortgage Securities Fund

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BOND & MORTGAGE SECURITIES FUND

Supplement Text

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Supplement dated June 15, 2012

to the Class R-1, Class R-2, Class R-3, Class R-4 and Class R-5 Shares Prospectus

for Principal Funds, Inc.

dated February 29, 2012

(as supplemented on March 16, 2012 and April 23, 2012)

This supplement updates information currently in the Prospectus. Retain this supplement with the Prospectus.  

FUND SUMMARIES

Investment Strategy, Heading

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Under the Principal Investment Strategies heading, delete the second and third sentences in the second paragraph and substitute:    

Investment Strategy, Narrative

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The Fund may utilize derivative strategies for hedging or managing fixed income exposure. Specifically, the  

Fund may invest in Treasury futures or interest rate swaps to manage the fixed-income exposure (including for  

hedging purposes) and credit default swaps to increase or decrease, in an efficient manner, exposures to  

certain sectors or individual issuers.  

Bond & Mortgage Securities Fund | R-1

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PBOMX

Bond & Mortgage Securities Fund | R-2

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PBMNX

Bond & Mortgage Securities Fund | R-3

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PBMMX

Bond & Mortgage Securities Fund | R-5

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PBMPX

Bond & Mortgage Securities Fund | R-4

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PBMSX