UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 1) PennyMac Mortgage Investment Trust (Name of Issuer) Common Shares, par value $0.01 per share (Title of Class of Securities) 70931T103 (CUSIP Number) December 31, 2009 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [ ] Rule 13d-1(b) [X] Rule 13d-1(c) [ ] Rule 13d-1(d) ---------------- *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). Page 1 of 16 Pages CUSIP No. 70931T103 13G/A Page 2 of 16 Pages -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS Highbridge International LLC -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (see instructions) (a) [X] (b) [ ] -------------------------------------------------------------------------------- (3) SEC USE ONLY -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION Cayman Islands, British West Indies -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 819,469 Common Shares OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 819,469 Common Shares -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 819,469 Common Shares -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (see instructions) [ ] -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 4.90% -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON (see instructions) OO -------------------------------------------------------------------------------- CUSIP No. 70931T103 13G/A Page 3 of 16 Pages -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS Highbridge Long/Short Equity Fund, L.P. -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (see instructions) (a) [X] (b) [ ] -------------------------------------------------------------------------------- (3) SEC USE ONLY -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION State of Delaware -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 131,461 Common Shares OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 131,461 Common Shares -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 131,461 Common Shares -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (see instructions) [ ] -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 0.79% -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON (see instructions) PN -------------------------------------------------------------------------------- CUSIP No. 70931T103 13G/A Page 4 of 16 Pages -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS Highbridge Long/Short Equity Fund, Ltd. -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (see instructions) (a) [X] (b) [ ] -------------------------------------------------------------------------------- (3) SEC USE ONLY -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION Cayman Islands, British West Indies -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 266,445 Common Shares OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 266,445 Common Shares -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 266,445 Common Shares -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (see instructions) [ ] -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 1.59% -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON (see instructions) OO -------------------------------------------------------------------------------- CUSIP No. 70931T103 13G/A Page 5 of 16 Pages -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS Highbridge Long/Short Institutional Fund, Ltd. -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (see instructions) (a) [X] (b) [ ] -------------------------------------------------------------------------------- (3) SEC USE ONLY -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION Cayman Islands, British West Indies -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 63,969 Common Shares OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 63,969 Common Shares -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 63,969 Common Shares -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (see instructions) [ ] -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 0.38% -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON (see instructions) OO -------------------------------------------------------------------------------- CUSIP No. 70931T103 13G/A Page 6 of 16 Pages -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS Triton 245 Ltd. -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (see instructions) (a) [X] (b) [ ] -------------------------------------------------------------------------------- (3) SEC USE ONLY -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION Cayman Islands, British West Indies -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 22,270 Common Shares OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 22,270 Common Shares -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 22,270 Common Shares -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (see instructions) [ ] -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 0.13% -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON (see instructions) OO -------------------------------------------------------------------------------- CUSIP No. 70931T103 13G/A Page 7 of 16 Pages -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS Highbridge Managed Portfolio Master, Ltd. -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (see instructions) (a) [X] (b) [ ] -------------------------------------------------------------------------------- (3) SEC USE ONLY -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION Cayman Islands, British West Indies -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 32,610 Common Shares OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 32,610 Common Shares -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 32,610 Common Shares -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (see instructions) [ ] -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 0.19% -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON (see instructions) OO -------------------------------------------------------------------------------- CUSIP No. 70931T103 13G/A Page 8 of 16 Pages -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS Highbridge Long-Term Equity Master Fund, L.P. -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (see instructions) (a) [X] (b) [ ] -------------------------------------------------------------------------------- (3) SEC USE ONLY -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION State of Delaware -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 17,776 Common Shares OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 17,776 Common Shares -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 17,776 Common Shares -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (see instructions) [ ] -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 0.11% -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON (see instructions) PN -------------------------------------------------------------------------------- CUSIP No. 70931T103 13G/A Page 9 of 16 Pages -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS Highbridge Capital Management, LLC -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (see instructions) (a) [X] (b) [ ] -------------------------------------------------------------------------------- (3) SEC USE ONLY -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION State of Delaware -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 1,354,000 Common Shares OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 1,354,000 Common Shares -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,354,000 Common Shares -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (see instructions) [ ] -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 8.09% -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON (see instructions) OO -------------------------------------------------------------------------------- CUSIP No. 70931T103 13G/A Page 10 of 16 Pages -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS Glenn Dubin -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (see instructions) (a) [X] (b) [ ] -------------------------------------------------------------------------------- (3) SEC USE ONLY -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION United States -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 1,354,000 Common Shares OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 1,354,000 Common Shares -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,354,000 Common Shares -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (see instructions) [ ] -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 8.09% -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON (see instructions) IN -------------------------------------------------------------------------------- CUSIP No. 70931T103 13G/A Page 11 of 16 Pages This Amendment No. 1 (this "Amendment") amends the statement on Schedule 13G filed on August 11, 2009 (the "Original Schedule 13G" and the Original Schedule 13G as amended, the "Schedule 13G"), with respect to the common shares of beneficial interest, $0.01 par value (the "Common Shares"), of PennyMac Mortgage Investment Trust, a Maryland real estate investment trust (the "Company"). Capitalized terms used herein and not otherwise defined in this Amendment have the meanings set forth in the Schedule 13G. This Amendment amends and restates Items 2(a), 2(b), 2(c) and 4 in their entirety as set forth below. Item 2(a). Name of Person Filing Item 2(b). Address of Principal Business Office Item 2(c). Citizenship HIGHBRIDGE INTERNATIONAL LLC ---------------------------- c/o Harmonic Fund Services The Cayman Corporate Centre, 4th Floor 27 Hospital Road Grand Cayman, Cayman Islands, British West Indies Citizenship: Cayman Islands, British West Indies HIGHBRIDGE LONG/SHORT EQUITY FUND, L.P. --------------------------------------- c/o Highbridge Capital Management, LLC 40 West 57th Street, 33rd Floor New York, New York 10019 Citizenship: State of Delaware HIGHBRIDGE LONG/SHORT EQUITY FUND, LTD. --------------------------------------- c/o Harmonic Fund Services The Cayman Corporate Centre, 4th Floor 27 Hospital Road Grand Cayman, Cayman Islands, British West Indies Citizenship: Cayman Islands, British West Indies HIGHBRIDGE LONG/SHORT INSTITUTIONAL FUND, LTD. ---------------------------------------------- c/o Harmonic Fund Services The Cayman Corporate Centre, 4th Floor 27 Hospital Road Grand Cayman, Cayman Islands, British West Indies Citizenship: Cayman Islands, British West Indies TRITON 245 LTD. --------------- Cricket Square Hutchins Drive, P.O. Box 2681 GT Grand Cayman, Cayman Islands, British West Indies Citizenship: Cayman Islands, British West Indies HIGHBRIDGE MANAGED PORTFOLIO MASTER, LTD. ----------------------------------------- Walkers Corporate Services Limited, Walker House 87 Mary Street George Town, Grand Cayman KY1-9005, Cayman Islands, British West Indies Citizenship: Cayman Islands, British West Indies CUSIP No. 70931T103 13G/A Page 12 of 16 Pages HIGHBRIDGE LONG-TERM EQUITY MASTER FUND, L.P. --------------------------------------------- 40 West 57th Street, 33rd Floor New York, NY 10019 Citizenship: State of Delaware HIGHBRIDGE CAPITAL MANAGEMENT, LLC ---------------------------------- 40 West 57th Street, 33rd Floor New York, New York 10019 Citizenship: State of Delaware GLENN DUBIN ----------- c/o Highbridge Capital Management, LLC 40 West 57th Street, 33rd Floor New York, New York 10019 Citizenship: United States Item 4. Ownership Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1. (a) Amount beneficially owned: As of December 31, 2009, (i) Highbridge International LLC beneficially owned 819,469 Common Shares, (ii) Highbridge Long/Short Equity Fund, L.P. beneficially owned 131,461 Common Shares, (iii) Highbridge Long/Short Equity Fund, Ltd. beneficially owned 266,445 Common Shares, (iv) Highbridge Long/Short Institutional Fund, Ltd. beneficially owned 63,969 Common Shares, (v) Triton 245 Ltd. beneficially owned 22,270 Common Shares (vi) Highbridge Managed Portfolio Master, Ltd. beneficially owned 32,610 Common Shares, (vii) Highbridge Long-Term Equity Master Fund, L.P. beneficially owned 17,776 Common Shares and (viii) each of Highbridge Capital Management, LLC and Glenn Dubin may have been deemed the beneficial owner of the 1,354,000 Common Shares beneficially owned by Highbridge International LLC, Highbridge Long/Short Equity Fund, L.P., Highbridge Long/Short Equity Fund, Ltd., Highbridge Long/Short Institutional Fund, Ltd., Triton 245 Ltd., Highbridge Managed Portfolio Master, Ltd. and Highbridge Long-Term Equity Master Fund, L.P. Highbridge Capital Management, LLC is the trading manager of Highbridge International LLC, Highbridge Long/Short Equity Fund, L.P., Highbridge Long/Short Equity Fund, Ltd., Highbridge Long/Short Institutional Fund, Ltd., and Highbridge Long-Term Equity Master Fund, L.P. Highbridge Capital Management, LLC is an advisor to Triton 245 Ltd and Highbridge Managed Portfolio Master, Ltd. Glenn Dubin is the Chief Executive Officer of Highbridge Capital Management, LLC. The foregoing should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of Common Shares owned by another Reporting Person. In addition, each of Highbridge Capital Management, LLC and Glenn Dubin disclaims beneficial ownership of Common Shares held by Highbridge International LLC, Highbridge Long/Short Equity Fund, L.P., Highbridge Long/Short Equity Fund, Ltd., Highbridge Long/Short Institutional Fund, Ltd., Triton 245 Ltd., Highbridge Managed Portfolio Master, Ltd. and Highbridge Long-Term Equity Master Fund, L.P. (b) Percent of class: The Company's Quarterly Report for the quarterly period ended September 30, 2009, filed on Form 10-Q on November 6, 2009, indicates that as of November CUSIP No. 70931T103 13G/A Page 13 of 16 Pages 5, 2009, there were 16,735,317 Common Shares issued and outstanding. Therefore, as of December 31, 2009, based on the Company's outstanding Common Shares (i) Highbridge International LLC may have been deemed to beneficially own 4.90% of the outstanding Common Shares of the Company, (ii) Highbridge Long/Short Equity Fund, L.P. may have been deemed to beneficially own 0.79% of the outstanding Common Shares of the Company, (iii) Highbridge Long/Short Equity Fund, Ltd. may have been deemed to beneficially own 1.59% of the outstanding Common Shares of the Company, (iv) Highbridge Long/Short Institutional Fund, Ltd. may have been deemed to beneficially own 0.38% of the outstanding Common Shares of the Company, (v) Triton 245 Ltd. may have been deemed to beneficially own 0.13% of the outstanding Common Shares of the Company, (vi) Highbridge Managed Portfolio Master, Ltd. may have been deemed to beneficially own 0.19% of the outstanding Common Shares of the Company, (vii) Highbridge Long-Term Equity Master Fund, L.P. may have been deemed to beneficially own 0.11% of the outstanding Common Shares of the Company and(viii) each of Highbridge Capital Management, LLC and Glenn Dubin may have been deemed to beneficially own 8.09% of the outstanding Common Shares of the Company. The foregoing should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of Common Shares owned by another Reporting Person. (c) Number of shares as to which such person has: (i) Sole power to vote or to direct the vote 0 (ii) Shared power to vote or to direct the vote See Item 4(a) (iii) Sole power to dispose or to direct the disposition of 0 (iv) Shared power to dispose or to direct the disposition of See Item 4(a) Exhibits: Exhibit I: Joint Filing Agreement, dated as of February 12, 2010, by and among Highbridge International LLC, Highbridge Long/Short Equity Fund, L.P., Highbridge Long/Short Equity Fund, Ltd., Highbridge Long/Short Institutional Fund, Ltd., Triton 245 Ltd., Highbridge Managed Portfolio Master, Ltd., Highbridge Long-Term Equity Master Fund, L.P., Highbridge Capital Management, LLC and Glenn Dubin. CUSIP No. 70931T103 13G/A Page 14 of 16 Pages SIGNATURES After reasonable inquiry and to the best of its knowledge and belief, each of the undersigned certifies that the information with respect to it set forth in this statement is true, complete, and correct. Dated: February 12, 2010 HIGHBRIDGE CAPITAL MANAGEMENT, LLC HIGHBRIDGE INTERNATIONAL LLC By: Highbridge Capital Management, LLC its Trading Manager By: /s/ John Oliva By: /s/ John Oliva ---------------------------------- --------------------------------- Name: John Oliva Name: John Oliva Title: Managing Director Title: Managing Director HIGHBRIDGE LONG/SHORT EQUITY FUND, HIGHBRIDGE LONG/SHORT EQUITY FUND, L.P. LTD. By: Highbridge Capital Management, LLC By: Highbridge Capital Management, LLC its Trading Manager its Trading Manager By: /s/ John Oliva By: /s/ John Oliva ---------------------------------- --------------------------------- Name: John Oliva Name: John Oliva Title: Managing Director Title: Managing Director HIGHBRIDGE LONG/SHORT INSTITUTIONAL TRITON 245 LTD. FUND, LTD. By: Highbridge Capital Management, LLC By: Highbridge Capital Management, LLC its Trading Manager its Advisor By: /s/ John Oliva By: /s/ John Oliva ---------------------------------- --------------------------------- Name: John Oliva Name: John Oliva Title: Managing Director Title: Managing Director HIGHBRIDGE MANAGED PORTFOLIO MASTER, HIGHBRIDGE LONG-TERM EQUITY MASTER LTD. FUND, L.P. By: Highbridge Capital Management, LLC By: Highbridge Capital Management, LLC its Advisor its Trading Manager By: /s/ John Oliva By: /s/ John Oliva ---------------------------------- --------------------------------- Name: John Oliva Name: John Oliva Title: Managing Director Title: Managing Director /s/ Glenn Dubin ---------------------------------- GLENN DUBIN CUSIP No. 70931T103 13G/A Page 15 of 16 Pages EXHIBIT I JOINT FILING AGREEMENT This will confirm the agreement by and among the undersigned that the Schedule 13G filed with the Securities and Exchange Commission on or about the date hereof with respect to the beneficial ownership by the undersigned of the Common Shares, $0.01 par value, of PennyMac Mortgage Investment Trust, is being filed, and all amendments thereto will be filed, on behalf of each of the persons and entities named below in accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended. This Agreement may be executed in two or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument. Dated as of February 12, 2010 HIGHBRIDGE CAPITAL MANAGEMENT, LLC HIGHBRIDGE INTERNATIONAL LLC By: Highbridge Capital Management, LLC its Trading Manager By: /s/ John Oliva By: /s/ John Oliva ---------------------------------- --------------------------------- Name: John Oliva Name: John Oliva Title: Managing Director Title: Managing Director HIGHBRIDGE LONG/SHORT EQUITY FUND, HIGHBRIDGE LONG/SHORT EQUITY FUND, L.P. LTD. By: Highbridge Capital Management, LLC By: Highbridge Capital Management, LLC its Trading Manager its Trading Manager By: /s/ John Oliva By: /s/ John Oliva ---------------------------------- --------------------------------- Name: John Oliva Name: John Oliva Title: Managing Director Title: Managing Director HIGHBRIDGE LONG/SHORT INSTITUTIONAL TRITON 245 LTD. FUND, LTD. By: Highbridge Capital Management, LLC By: Highbridge Capital Management, LLC its Trading Manager its Advisor By: /s/ John Oliva By: /s/ John Oliva ---------------------------------- --------------------------------- Name: John Oliva Name: John Oliva Title: Managing Director Title: Managing Director HIGHBRIDGE MANAGED PORTFOLIO MASTER, HIGHBRIDGE LONG-TERM EQUITY MASTER LTD. FUND, L.P. By: Highbridge Capital Management, LLC By: Highbridge Capital Management, LLC its Advisor its Trading Manager By: /s/ John Oliva By: /s/ John Oliva ---------------------------------- --------------------------------- Name: John Oliva Name: John Oliva Title: Managing Director Title: Managing Director CUSIP No. 70931T103 13G/A Page 16 of 16 Pages /s/ Glenn Dubin ---------------------------------- GLENN DUBIN