Exhibit 99.1
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                                   Footnotes
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(1)  The stockholder is Warburg Pincus  Ventures,  L.P.  ("Ventures").  Ventures
     beneficially  owns  3,531,328  shares of common stock  ("Common  Stock") of
     Kyphon Inc. (the "Issuer"). The sole general partner of Ventures is Warburg
     Pincus  Partners  LLC, a New York limited  liability  company ("WPP LLC") a
     subsidiary of Warburg  Pincus & Co. ("WP") a New York general  partnership.
     Warburg  Pincus LLC (formerly  E.M.  Warburg Pincus & Co., LLC), a New York
     limited  liability company ("WP LLC"),  manages Ventures.  By reason of the
     provisions of Rule 16a-1 of the Exchange Act, WPP LLC, WP and WP LLC may be
     deemed to be the  beneficial  owners of the Common  Stock held by Ventures,
     although WPP LLC, WP and WP LLC disclaim beneficial ownership of the Common
     Stock except to the extent of any indirect pecuniary interest therein.  Ms.
     Weatherman,  a director  of the  Issuer,  is a general  partner of WP and a
     member of WP LLC. As such, Ms Weatherman  may be deemed to have an indirect
     pecuniary  interest  (within the meaning of Rule 16a-1 of the Exchange Act)
     in an indeterminate  portion of the shares  beneficially owned by Ventures,
     WP LLC, WP and WPP LLC. Ms. Weatherman  disclaims  beneficial  ownership of
     such  shares  except  to the  extent  of any  indirect  pecuniary  interest
     therein. Ms. Weatherman does not directly own any shares of common stock of
     the Issuer.

(2)  On July 12, 2005,  Ventures  distributed an aggregate of 2,973,526 shares
     of Common Stock to its partners.

(3)  Price not applicable.