UNITED STATES              ----------------------------
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                                  SCHEDULE 14A

           Proxy Statement Pursuant to Section 14(a) of the Securities
                      Exchange Act of 1934 (Amendment No. )


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                          BARON INVESTMENT FUNDS TRUST
                            (f/k/a Baron Asset Fund)
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                (Name of Registrant as Specified In Its Charter)

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SEC 1913 (04-05)


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[registered castle logo]                                [Photo]

B A R O N
F U N D S (r)



DEAR BARON ASSET FUND SHAREHOLDER,

I am writing to explain a proposed  change in a stated  investment goal of Baron
Asset  Fund.  The Fund's  current  goal is to achieve  capital  appreciation  by
investing  primarily in small and mid-cap  companies.  We would like to formally
change Baron Asset's investment  strategy to focus its investments  primarily on
mid-cap companies. By far the largest portion of Baron Asset Fund's portfolio is
already  invested  in  securities  of mid- cap  companies,  many of  which  have
appreciated  significantly  since they were acquired as small cap companies.  We
think  focusing  on mid-cap  securities  is in the best  interest of Baron Asset
Fund's  shareholders.  I urge you to vote for this change.  Thank you in advance
for voting.

The Fund's Board of Trustees has recommended  you vote FOR the proposed  change.
PLEASE VOTE YOUR PROXY. If you have any questions  about voting,  please call us
at 1.800.99.BARON.

Thank you,

/s/ Ronald Baron

    Ronald Baron
    Chief Investment Officer and
    Co-Portfolio Manager
    December 2006