================================================================================

                                 UNITED STATES
                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549

                               -----------------

                                   FORM N-PX

                               -----------------

                    ANNUAL REPORT OF PROXY VOTING RECORD OF
                  REGISTERED MANAGEMENT INVESTMENT COMPANIES

                 Investment Company Act file number 811-02464

                               -----------------

                              MFS SERIES TRUST IX
              (Exact name of registrant as specified in charter)

                               -----------------

              111 Huntington Avenue, Boston, Massachusetts 02199
              (Address of principal executive offices) (Zip code)

                               -----------------

                             Christopher R. Bohane
                   Massachusetts Financial Services Company
                             111 Huntington Avenue
                          Boston, Massachusetts 02199
                   (Name and address of agents for service)

      Registrant's telephone number, including area code: (617) 954-5000

                               -----------------

               Date of fiscal year end: April 30 and October 31*

             Date of reporting period: July 1, 2016 - June 30, 2017

* MFS Inflation-Adjusted Bond Fund, a series of the Registrant, has a fiscal
  year end of October 31. The fiscal year ends of the remaining series of the
  Registrant are April 30.

================================================================================




ITEM 1. PROXY VOTING RECORD.




******************************* FORM N-Px REPORT *******************************

ICA File Number: 811-02464
Reporting Period: 07/01/2016 - 06/30/2017
MFS Series Trust IX









=========================== MFS Corporate Bond Fund ============================


MFS SERIES TRUST XIV - MFS INSTITUTIONAL MONEY MARKET PORTFOLIO

Ticker:                      Security ID:  55291X109
Meeting Date: MAR 23, 2017   Meeting Type: Written Consent
Record Date:

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1.1   Elect Director Steven E. Buller         For       For          Management
1.2   Elect Director John A. Caroselli        For       For          Management
1.3   Elect Director Maureen R. Goldfarb      For       For          Management
1.4   Elect Director David H. Gunning         For       For          Management
1.5   Elect Director Michael Hegarty          For       For          Management
1.6   Elect Director John P. Kavanaugh        For       For          Management
1.7   Elect Director Robert J. Manning        For       For          Management
1.8   Elect Director Clarence Otis, Jr.       For       For          Management
1.9   Elect Director Maryanne L. Roepke       For       For          Management
1.10  Elect Director Robin A. Stelmach        For       For          Management
1.11  Elect Director Laurie J. Thomsen        For       For          Management




====================== MFS Inflation - Adjusted Bond Fund ======================


MFS SERIES TRUST XIV - MFS INSTITUTIONAL MONEY MARKET PORTFOLIO

Ticker:                      Security ID:  55291X109
Meeting Date: MAR 23, 2017   Meeting Type: Written Consent
Record Date:

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1.1   Elect Director Steven E. Buller         For       For          Management
1.2   Elect Director John A. Caroselli        For       For          Management
1.3   Elect Director Maureen R. Goldfarb      For       For          Management
1.4   Elect Director David H. Gunning         For       For          Management
1.5   Elect Director Michael Hegarty          For       For          Management
1.6   Elect Director John P. Kavanaugh        For       For          Management
1.7   Elect Director Robert J. Manning        For       For          Management
1.8   Elect Director Clarence Otis, Jr.       For       For          Management
1.9   Elect Director Maryanne L. Roepke       For       For          Management
1.10  Elect Director Robin A. Stelmach        For       For          Management
1.11  Elect Director Laurie J. Thomsen        For       For          Management




========================== MFS Limited Maturity Fund ===========================


MFS SERIES TRUST XIV - MFS INSTITUTIONAL MONEY MARKET PORTFOLIO

Ticker:                      Security ID:  55291X109
Meeting Date: MAR 23, 2017   Meeting Type: Written Consent
Record Date:

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1.1   Elect Director Steven E. Buller         For       For          Management
1.2   Elect Director John A. Caroselli        For       For          Management
1.3   Elect Director Maureen R. Goldfarb      For       For          Management
1.4   Elect Director David H. Gunning         For       For          Management
1.5   Elect Director Michael Hegarty          For       For          Management
1.6   Elect Director John P. Kavanaugh        For       For          Management
1.7   Elect Director Robert J. Manning        For       For          Management
1.8   Elect Director Clarence Otis, Jr.       For       For          Management
1.9   Elect Director Maryanne L. Roepke       For       For          Management
1.10  Elect Director Robin A. Stelmach        For       For          Management
1.11  Elect Director Laurie J. Thomsen        For       For          Management




===================== MFS Municipal Limited Maturity Fund ======================


COMMONWEALTH OF PUERTO RICO

Ticker:                      Security ID:  745145ZA3
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

COMMONWEALTH OF PUERTO RICO

Ticker:                      Security ID:  745145ZB1
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

COMMONWEALTH OF PUERTO RICO

Ticker:                      Security ID:  745145ZC9
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

MFS SERIES TRUST XIV - MFS INSTITUTIONAL MONEY MARKET PORTFOLIO

Ticker:                      Security ID:  55291X109
Meeting Date: MAR 23, 2017   Meeting Type: Written Consent
Record Date:

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1.1   Elect Director Steven E. Buller         For       For          Management
1.2   Elect Director John A. Caroselli        For       For          Management
1.3   Elect Director Maureen R. Goldfarb      For       For          Management
1.4   Elect Director David H. Gunning         For       For          Management
1.5   Elect Director Michael Hegarty          For       For          Management
1.6   Elect Director John P. Kavanaugh        For       For          Management
1.7   Elect Director Robert J. Manning        For       For          Management
1.8   Elect Director Clarence Otis, Jr.       For       For          Management
1.9   Elect Director Maryanne L. Roepke       For       For          Management
1.10  Elect Director Robin A. Stelmach        For       For          Management
1.11  Elect Director Laurie J. Thomsen        For       For          Management


--------------------------------------------------------------------------------

PUERTO RICO COMWLTH REF-PUB IMPT

Ticker:                      Security ID:  74514LUR6
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO COMWLTH REF-PUB IMPT

Ticker:                      Security ID:  74514LXD4
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  7452686K3
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  7452688D7
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QAL6
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QAM4
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QCM2
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QDC3
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QDD1
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QEH1
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QER9
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QLJ9
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QLM2
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QLR1
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QLS9
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QLU4
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QPJ5
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QSY9
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QZC9
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO ELECTRIC POWER AUTHORITY

Ticker:                      Security ID:  74526QZJ4
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO HIGHWAY & TRANSPORTATION AUTHORITY

Ticker:                      Security ID:  745190AU2
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO HIGHWAY & TRANSPORTATION AUTHORITY

Ticker:                      Security ID:  745190AV0
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO HIGHWAY & TRANSPORTATION AUTHORITY

Ticker:                      Security ID:  745190E53
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO HIGHWAY & TRANSPORTATION AUTHORITY

Ticker:                      Security ID:  745190E61
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO HIGHWAY & TRANSPORTATION AUTHORITY

Ticker:                      Security ID:  745190HF8
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO HIGHWAY & TRANSPORTATION AUTHORITY

Ticker:                      Security ID:  745190M70
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO HIGHWAY & TRANSPORTATION AUTHORITY

Ticker:                      Security ID:  745190UK2
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO HIGHWAY & TRANSPORTATION AUTHORITY

Ticker:                      Security ID:  745181N52
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO HIGHWAY & TRANSPORTATION AUTHORITY

Ticker:                      Security ID:  745181P35
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO HIGHWAY & TRANSPORTATION AUTHORITY

Ticker:                      Security ID:  745181ZK6
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO INDL TOURIST

Ticker:                      Security ID:  745272CU6
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry


--------------------------------------------------------------------------------

PUERTO RICO INDL TOURIST

Ticker:                      Security ID:  745272EL4
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry


--------------------------------------------------------------------------------

PUERTO RICO INDL TOURIST

Ticker:                      Security ID:  745272ET7
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry


--------------------------------------------------------------------------------

PUERTO RICO INDL TOURIST

Ticker:                      Security ID:  745272EU4
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry


--------------------------------------------------------------------------------

PUERTO RICO INDL TOURIST

Ticker:                      Security ID:  745272EW0
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry


--------------------------------------------------------------------------------

PUERTO RICO INDL TOURIST

Ticker:                      Security ID:  745272EX8
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry


--------------------------------------------------------------------------------

PUERTO RICO INDL TOURIST

Ticker:                      Security ID:  745272EY6
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry


--------------------------------------------------------------------------------

PUERTO RICO INFRASTRUCTURE FING AUTH SPL TAX REVENUE

Ticker:                      Security ID:  745220FG3
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO INFRASTRUCTURE FING AUTH SPL TAX REVENUE

Ticker:                      Security ID:  745220FH1
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO INFRASTRUCTURE FING AUTH SPL TAX REVENUE

Ticker:                      Security ID:  745220FN8
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO INFRASTRUCTURE FING AUTH SPL TAX REVENUE

Ticker:                      Security ID:  745220FP3
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO INFRASTRUCTURE FING AUTH SPL TAX REVENUE

Ticker:                      Security ID:  745220FQ1
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO INFRASTRUCTURE FING AUTH SPL TAX REVENUE

Ticker:                      Security ID:  745220FR9
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO INFRASTRUCTURE FING AUTH SPL TAX REVENUE

Ticker:                      Security ID:  745220FS7
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO MUN FIN AGY

Ticker:                      Security ID:  745277PD9
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO PUB BLDGS AUTH REVGTD

Ticker:                      Security ID:  745235B75
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO PUB BLDGS AUTH REVGTD

Ticker:                      Security ID:  745235K59
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO PUB BLDGS AUTH REVGTD

Ticker:                      Security ID:  745235TJ0
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

PUERTO RICO PUB BLDGS AUTH REVGTD

Ticker:                      Security ID:  745235TK7
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.


--------------------------------------------------------------------------------

UNIVERSITY PUERTO R UNIV

Ticker:                      Security ID:  914811PX6
Meeting Date: MAR 30, 2017   Meeting Type: Written Consent
Record Date:  NOV 17, 2016

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     By Marking For I Direct The             None      For          Management
      Institution Holding My Bonds to
      Transmit and Confirm My Bond Holding
      Information for Recording In The
      Registry. By Marking Against My Bonds
      Shall Be Missing From The Registry.




========================== MFS Total Return Bond Fund ==========================


MFS SERIES TRUST XIV - MFS INSTITUTIONAL MONEY MARKET PORTFOLIO

Ticker:                      Security ID:  55291X109
Meeting Date: MAR 23, 2017   Meeting Type: Written Consent
Record Date:

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1.1   Elect Director Steven E. Buller         For       For          Management
1.2   Elect Director John A. Caroselli        For       For          Management
1.3   Elect Director Maureen R. Goldfarb      For       For          Management
1.4   Elect Director David H. Gunning         For       For          Management
1.5   Elect Director Michael Hegarty          For       For          Management
1.6   Elect Director John P. Kavanaugh        For       For          Management
1.7   Elect Director Robert J. Manning        For       For          Management
1.8   Elect Director Clarence Otis, Jr.       For       For          Management
1.9   Elect Director Maryanne L. Roepke       For       For          Management
1.10  Elect Director Robin A. Stelmach        For       For          Management
1.11  Elect Director Laurie J. Thomsen        For       For          Management

========== END NPX REPORT



                                  SIGNATURES

Pursuant to the requirements of the Investment Company Act of 1940, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.

Registrant: MFS SERIES TRUST IX

By (Signature and Title):  David DiLorenzo*
                           -------------------------------------------
                           David DiLorenzo, President and Principal
                           Executive Officer

Date: August 28, 2017

*By (Signature and Title)  /s/ Susan A. Pereira
                           -------------------------------------------
                           Susan A. Pereira, as attorney-in-fact

*    Executed by Susan A. Pereira on behalf of David DiLorenzo pursuant to a
     Power of Attorney dated June 1, 2017. (1)

(1)  Incorporated by reference to MFS Series Trust XIII (File Nos. 2-74959 and
     811-03327) Post-Effective Amendment No. 65 filed with the SEC via EDGAR on
     June 27, 2017.