X0303 4 2010-01-29 0001376812 Patriot Coal CORP PCX 0001052192 CASCADE INVESTMENT LLC 2365 CARILLON POINT KIRKLAND WA 98033 1 See Footnote (3) 0000902012 GATES WILLIAM H III ONE MICROSOFT WAY REDMOND WA 98052 1 (1) Common Stock 2010-01-29 4 J 0 17421 18.01 D 2391231 D The shares were transferred pursuant to a letter agreement (as amended, the "Letter Agreement"), which provided that certain persons including the reporting persons herein would transfer to Mr. Paul Vining shares of Common Stock in an amount determined as set forth in the Letter Agreement. The foregoing discussion of the Letter Agreement is not intended to be a complete statement of all of the material terms thereof and is qualified in its entirety by the Letter Agreement filed as Exhibit 10.1 to Patriot Coal Corporation's quarterly report on Form 10-Q filed on August 7, 2009 (File No. 001-33466). On August 11, 2008, the Common Stock of Patriot Coal Corporation split 2-for-1, resulting in the reporting persons' acquisition of 1,204,326 additional shares of Common Stock. The reporting persons may be deemed to be a member of a group beneficially owning 10% or more of the Common Stock of the issuer within the meaning of Section 13(d) of the Securities Exchange Act of 1934. The reporting persons disclaim beneficial ownership of all securities other than those reported above, and this report shall not be deemed an admission that such a group exists or that the reporting persons are the beneficial owners of the securities of such group for purposes of Section 16 or for any other purpose. /s/ Cascade Investment, L.L.C. by Alan Heuberger, Attorney-in-fact for Michael Larson, Business Manager 2010-02-02 /s/ Alan Heuberger, Attorney-in-fact for William H. Gates III 2010-02-02