What changed in this filing

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Item 9A. Controls and Procedures

2026-03-04 compared with 2025-03-05 · 108 added, 118 removed, 641 unchanged (26% of the section changed)

42 unchanged sentences

Position With Our General Partner

Steven Bender 69 Executive Vice President, Chief Financial Officer and Director

Chao 76 Executive Chairman of the Board of Directors

Chao 78 Senior Chairman of the Board of Directors

Benjamin Ederington 55 Executive Vice President, Legal and External Affairs and Director

Stephen Finley

Jean-Marc Gilson

62 President, Chief Executive Officer and Director

Steven Bender 68 Executive Vice President, Chief Financial Officer and Director

Benjamin Ederington 54 Executive Vice President, Performance & Essential Materials, General Counsel, Chief Administrative Officer and Director

Stephen Finley

46 Vice President and Chief Accounting Officer

60 Senior Vice President, Olefin Materials & Corporate Procurement

48 Vice President, Olefins and Polyethylene

Woelfel 70 Director

Steven Bender .

Bender has been our general partner's Executive Vice President and Chief Financial Officer since February 2021 and a director since our general partner's formation in March 2014.

Bender served as our general partner's Senior Vice President and Chief Financial Officer from March 2014 to February 2021 and as Treasurer from April 2015 to February 2019.

Bender has also been Westlake's Executive Vice President and Chief Financial Officer since July 2017.

From February 2008 to July 2017, Mr.

Bender served as Westlake's Senior Vice President and Chief Financial Officer.

In addition, Mr.

Bender served as Westlake's Treasurer from July 2011 to April 2017, a position he also held from February 2008 until December 2010.

From February 2007 to February 2008, Mr.

Bender served as Westlake's Vice President, Chief Financial Officer and Treasurer and, from June 2005 to February 2007, he was its Vice President and Treasurer.

Prior to joining Westlake, from June 2002 until June 2005, Mr.

Bender served as Vice President and Treasurer of KBR, Inc.

and, from 1996 to 2002, he held the position of Assistant Treasurer for Halliburton Company.

Prior to that, he held various financial positions within that company.

Additionally, he was employed by Texas Eastern Corporation for over a decade in a variety of increasingly responsible audit, finance and treasury positions.

Bender received a Bachelor of Business Administration from Texas A&M University and an M.B.A.

from Southern Methodist University.

Bender is also a Certified Public Accountant.

Chao has been Executive Chairman of the Board of Directors of our general partner since July 2024, a director since our general partner's formation in March 2014 and served as President and Chief Executive Officer from March 2014 to July 2024.

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from Columbia University.

Jean-Marc Gilson .

Gilson has been our general partner's President and Chief Executive Officer and a director since July 2024.

Gilson has also served as President and Chief Executive Officer of Westlake since July 2024.

Prior to joining Westlake, Mr.

Gilson served as President, Chief Executive Officer and Representative Director of Mitsubishi Chemical Group Corporation (formerly known as Mitsubishi Chemical Holdings Corporation), from April 2021 until April 2024.

From September 2014 until December 2020, Mr.

Gilson served as Chief Executive Officer of Roquette Frères.

Before that, Mr.

Gilson served as Vice-Chairman and Chief Operating Officer of NuSil Technology LLC.

Earlier in his career, Mr.

Gilson held various leadership roles at Dow Corning Corporation, including as Executive Vice President, Specialty Chemicals Business, before becoming Chief Executive Officer of Avantor Performance Materials, Inc.

Gilson holds a Master of Science in Chemical Engineering from the University of Liege in Belgium and a Master of Business Administration from the International Institute for Management Development in Switzerland.

Steven Bender .

Bender has been our general partner's Executive Vice President and Chief Financial Officer since February 2021 and a director since our general partner's formation in March 2014.

Bender served as our general partner's Senior Vice President and Chief Financial Officer from March 2014 to February 2021 and as Treasurer from April 2015 to February 2019.

Bender has also been Westlake's Executive Vice President and Chief Financial Officer since July 2017.

From February 2008 to July 2017, Mr.

Bender served as Westlake's Senior Vice President and Chief Financial Officer.

In addition, Mr.

Bender served as Westlake's Treasurer from July 2011 to April 2017, a position he also held from February 2008 until December 2010.

From February 2007 to February 2008, Mr.

Bender served as Westlake's Vice President, Chief Financial Officer and Treasurer and, from June 2005 to February 2007, he was its Vice President and Treasurer.

Prior to joining Westlake, from June 2002 until June 2005, Mr.

Bender served as Vice President and Treasurer of KBR, Inc.

and, from 1996 to 2002, he held the position of Assistant Treasurer for Halliburton Company.

Prior to that, he held various financial positions within that company.

Additionally, he was employed by Texas Eastern Corporation for over a decade in a variety of increasingly responsible audit, finance and treasury positions.

Bender received a Bachelor of Business Administration from Texas A&M University and an M.B.A.

from Southern Methodist University.

Bender is also a Certified Public Accountant.

Benjamin Ederington .

Ederington has been our general partner's Executive Vice President, Performance and Essential Materials, General Counsel and Chief Administrative Officer since May 2023 and a director since our general partner's formation in March 2014.

Ederington served as our general partner's Executive Vice President, General Counsel, Chief Administrative Officer and Corporate Secretary from March 2022 to May 2023 , Senior Vice President, General Counsel, Chief Administrative Officer and Corporate Secretary from February 2021 to March 2022 and as Vice President, General Counsel and Secretary from March 2014 to February 2021.

Ederington has also been Westlake's Executive Vice President, Performance and Essential Materials, General Counsel and Chief Administrative Officer since April 2023.

From March 2022 to April 2023, Mr.

Ederington served as Westlake's Executive Vice President , General Counsel, Chief Administrative Officer and Corporate Secretary;

Ederington has been our general partner's Executive Vice President, Legal and External Affairs since May 2025 and a director since our general partner's formation in March 2014.

Ederington served as our general partner's Executive Vice President, Performance and Essential Materials, General Counsel and Chief Administrative Officer from May 2023 to May 2025;

Executive Vice President, General Counsel, Chief Administrative Officer and Corporate Secretary from March 2022 to May 2023;

Senior Vice President, General Counsel, Chief Administrative Officer and Corporate Secretary from February 2021 to March 2022;

and as Vice President, General Counsel and Secretary from March 2014 to February 2021.

Ederington has also been Westlake's Executive Vice President, Legal and External Affairs since April 2025.

From April 2023 to April 2025, Mr.

Ederington served as Westlake's Executive Vice President, Performance and Essential Materials, General Counsel and Chief Administrative Officer;

from March 2022 to April 2023, he was its Executive Vice President, General Counsel, Chief Administrative Officer and Corporate Secretary;

from July 2017 to March 2022, he was its Senior Vice President, General Counsel, Chief Administrative Officer and Corporate Secretary;

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Friel holds a bachelor's of science degree in Accounting and Business Administration from the University of Kansas and is a Certified Public Accountant.

Jean-Marc Gilson .

Gilson has been our general partner's President and Chief Executive Officer and a director since July 2024.

Gilson has also served as President and Chief Executive Officer of Westlake since July 2024 and a director since February 2026.

Prior to joining Westlake, Mr.

From September 2014 until December 2020, Mr.

Gilson served as Chief Executive Officer of Roquette Frères.

Before that, Mr.

Gilson served as Vice-Chairman and Chief Operating Officer of NuSil Technology LLC.

Earlier in his career, Mr.

Holy has been our general partner's Vice President and Chief Accounting Officer since April 2024.

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He is a Chartered Financial Analyst and Certified Public Accountant.

Kenner has been our general partner's Senior Vice President, Olefin Materials & Corporate Procurement since March 2022.

Kenner has also been Westlake's Senior Vice President, Olefin Materials & Corporate Procurement since March 2022.

From January 2021 to March 2022, Mr.

Kenner served as Westlake's Senior Vice President, Operations;

from July 2017 to December 2020, he was its Senior Vice President, Chemical Manufacturing and, from July 2008 to July 2017, he was its Vice President, Manufacturing.

Kenner joined Westlake after a 19-year career at Valero Energy Corporation where he served as Vice President and General Manager of Valero's Delaware City Refinery and its Houston Refinery, as well as other leadership positions in Valero's refining system.

Kenner received a B.S.

in Aerospace Engineering from Texas A&M University and a M.S.

in Chemical Engineering from the University of Texas at Austin.

Moore has been our general partner's Vice President, Olefins and Polyethylene since August 2025.

In addition, Ms.

Moore has been Westlake's Vice President, Olefins and Polyethylene since April 2025.

From March 2022 to April 2025, Ms.

Moore served as Westlake's Vice President, Polyethylene;

from November 2019 to March 2022 she was its Business Director, Polyethylene;

from August 2018 to October 2019 she was its Business Manager, Polyethylene;

and from August 2010 to July 2018 she was its Commercial Manager, Olefins Products.

Prior to joining Westlake, Ms.

Moore held a number of positions in manufacturing, sales and business planning at Chevron Phillips Chemical Company in their Olefins and Polyethylene division.

Moore holds a B.S.

in Chemical Engineering and a Masters of Business Administration from Lamar University.

Woelfel has been a director of our general partner since November 2019 and serves on the audit and conflicts committees.

Since March 2013, Mr.

Woelfel has served as a director of Black & Veatch Holding Company, where he is currently a member of the Audit and Compensation and Development committees.

Woelfel was Chief Executive Officer and a director of NOVA Chemicals Corporation from November 2009 until May 2014.

Woelfel served as a director of Black & Veatch Holding Company from March 2013 to December 2025 and was Chief Executive Officer and a director of NOVA Chemicals Corporation from November 2009 until May 2014.

Prior to joining NOVA, Mr.

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Meetings of the Board

During the last fiscal year, our general partner's board of directors held ten meetings and our general partner's audit committee held seven meetings.

During the last fiscal year, our general partner's board of directors held nine meetings and our general partner's audit committee held seven meetings.

Our general partner's conflicts committee did not hold any meetings in the last fiscal year.

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A copy of our insider trading policy is filed as Exhibit 19 to this report.

Delinquent Section 16(a) Reports

Section 16(a) of the Exchange Act requires our directors, executive officers and persons who own more than 10% of our common units to file with the SEC and the NYSE initial reports of ownership and reports of changes in ownership of common units.

Based solely on a review of the copies of such reports filed electronically with the SEC and representations that no other reports were required, we believe that all of our directors and executive officers complied on a timely basis with all applicable filing requirements under Section 16(a) of the Exchange Act during 2024 and 2025, except that Mr.

Gilson filed, in each case after the time prescribed, a Form 4 reporting six acquisitions of common units, and a Form 4/A reporting one acquisition of common units.

Executive Compensation

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During 2025, Mr.

Albert Chao, who served as President and Chief Executive Officer until July 2024, devoted approximately 5% of his total business time to our general partner, our consolidated subsidiaries (including OpCo) and us and Jean-Marc Gilson, who was appointed President and Chief Executive Officer in July 2024, devoted approximately 5% of his total business time to our general partner, our consolidated subsidiaries (including OpCo) and us.

Jean-Marc Gilson devoted approximately 10% of his total business time to our general partner, our consolidated subsidiaries (including OpCo) and us and Mr.

Steven Bender devoted approximately 10% of his total business time to our general partner, our consolidated subsidiaries (including OpCo) and us.

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Named Executive Officers

For 2024, our named executive officers ("NEOs") consisted of our general partner's principal executive officers, Mr.

Albert Chao (in such position until July 15, 2024) and Mr.

Jean-Marc Gilson (appointed to such position on July 15, 2024), and our general partner's principal financial officer, Mr.

For 2025, our named executive officers ("NEOs") consisted of our general partner's principal executive officer, Mr.

Jean-Marc Gilson, and our general partner's principal financial officer, Mr.

Steven Bender.

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Willis Towers Watson also assists Westlake with general compensation consultation regarding employees other than the Westlake NEOs.

In 2024, Westlake paid Willis Towers Watson approximately $162,000 for compensation advisory services and approximately $2.1 million for other services (primarily related to the administration of Westlake's legacy defined benefit retirement plans).

In 2025, Westlake paid Willis Towers Watson approximately $227,000 for compensation advisory services and approximately $3.7 million for other services (primarily related to due diligence and integration support and the administration of Westlake's legacy defined benefit retirement plans).

The decision to engage Willis Towers Watson for the non-executive-compensation services of Westlake was made by Westlake management and approved by the Westlake Compensation Committee.

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To validate current peers and identify potential new peer companies, Willis Towers Watson conducts a comprehensive review using both objective and qualitative criteria that the Westlake Compensation Committee deems to be appropriate, including recent developments with current peer companies (e.g., merger and acquisition activity and changes in financial performance), revenue, industry classification, market capitalization and other financial data, peers of peers analysis, business and product portfolios, peers as identified by proxy advisory firms such as ISS and Glass Lewis, and business and labor market competitors, with an overall objective of achieving approximately a median ranking for Westlake within the Peer Group.

The following companies from both the chemicals and building products industries made up the Peer Group as adopted by the Westlake Compensation Committee for purposes of determining compensation for the Westlake NEOs for 2024:

The following companies from both the chemicals and building products industries made up the Peer Group as adopted by the Westlake Compensation Committee in November 2024 for purposes of determining compensation for the Westlake NEOs for 2025:

Builders FirstSource, Inc.

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The Sherwin-Williams Company

As disclosed in Westlake's 2024 Proxy Statement, in November 2023, as part of its annual evaluation process, and upon recommendation by Willis Towers Watson, the Westlake Compensation Committee determined, and the Westlake board of directors agreed, the 2024 selected Peer Group would be updated to achieve an approximately median ranking for Westlake relative to the peer group.

As recommended by Willis Towers Watson, the 2025 Peer Group reflects no changes from the previous year.

Going forward, the Westlake Compensation Committee will continue to evaluate and make changes in the Peer Group as warranted to reflect changes in the size, business profile and publicly-listed status of the companies to help ensure that companies comparable in size and business profile to Westlake are included and continue to be appropriate for the compensation decision-making process.

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WESTLAKE CHEMICAL PARTNERS GP LLC

Jean-Marc Gilson

Steven Bender

1 unchanged sentence

Stephen Finley

Jean-Marc Gilson

Executive Compensation

5 unchanged sentences

Portion Allocation (2)

Executive Chairman of the Board of Directors (since July 2024);

President and Chief Executive Officer (until July 2024)

2024 $ 1,172,923 (4)

Steven Bender

Executive Vice President and Chief Financial Officer

2025 $ 778,077 10.0 % $ 77,807

2 unchanged sentences

Jean-Marc Gilson

President and Chief Executive Officer (since July 2024)

2024 $ 528,846 5.0 % $ 26,442

Steven Bender

Executive Vice President and Chief Financial Officer

2024 $ 749,231 10.0 % $ 74,923

President and Chief Executive Officer

2025 $ 1,288,462 10.0 % $ 128,846

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(2) See "Compensation Discussion and Analysis—Overview" for more information on the portion of base salary allocated to us by Westlake.

Albert Chao served as President and Chief Executive Officer of our General Partner until July 15, 2024;

the totals for Mr.

Albert Chao reflect the portion of his base salary allocated to us by Westlake for the periods from January 1, 2024 through July 15, 2024, from January 1, 2023 through December 31, 2023 and from January 1, 2022 through December 31, 2022.

Gilson was appointed President and Chief Executive Officer of our General Partner on July 15, 2024;

the total for Mr.

Gilson reflects the portion of his base salary allocated to us by Westlake for the period from July 15, 2024 through December 31, 2024.

Gilson reflects the portion of his base salary allocated to us by Westlake for the periods from January 1, 2025 through December 31, 2025 and from July 15, 2024 through December 31, 2024.

The totals for Mr.

Bender reflect the portion of his base salary allocated to us by Westlake for the periods from January 1, 2025 through December 31, 2025, from January 1, 2024 through December 31, 2024 and from January 1, 2023 through December 31, 2023.

Albert Chao's base salary was decreased from $1,301,000 to $1,019,000 in July 2024 in connection with his transition from President and Chief Executive Officer to Executive Chairman of the Board of Directors.

Director Compensation

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(1) The amounts reflected in this column represent the grant date fair value of phantom unit awards granted to the non-employee directors, computed in accordance with FASB ASC Topic 718, as the product of (i) the number of phantom units granted and (ii) the average of the high and low prices of our common units reported on the New York Stock Exchange on the grant date.

For a discussion of the related valuation assumptions, please see Note 12 to our consolidated financial statements included in this report.

For a discussion of the related valuation assumptions, please see Note 12, "Unit-based Compensation," to our Consolidated Financial Statements included in this report.

As of December 31, 2025, Ms.

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The table below sets forth comparative information regarding:

(1) the annualized total compensation of our Chief Executive Officer, Mr.

Gilson, who has served as President and Chief Executive Officer since July 15, 2024, for the year ended December 31, 2024, determined on the basis set forth below;

(1) the annual total compensation of our Chief Executive Officer, Mr.

Gilson, for the year ended December 31, 2025, determined on the basis set forth below;

(2) the median of the annual total compensation of all seconded employees of Westlake that provide services to OpCo under the Services and Secondment Agreement, which excludes our Chief Executive Officer, for the year ended December 31, 2025, determined on the basis described below;

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However, for purposes of this disclosure, we have included the employees of Westlake and its other affiliates who are seconded to OpCo under the Services and Secondment Agreement for the production of ethylene (the "Seconded Employees").

For purposes of determining the median of the annual total compensation of our Seconded Employee population, excluding our Chief Executive Officer, for the year ended December 31, 2024, the applicable SEC rules require us to identify the median Seconded Employee by using either annual total compensation for all such employees or another consistently applied compensation measure.

For purposes of determining the median of the annual total compensation of our Seconded Employee population, excluding our Chief Executive Officer, for the year ended December 31, 2025, we referred to the same employee who was identified as our median Seconded Employee for 2024.

We determined that there have been no changes to the Seconded Employee population or Seconded Employee compensation arrangements in 2025 that we believe would significantly impact our pay ratio disclosure and thus require identification of a new median employee.

The applicable SEC rules require us to identify the median Seconded Employee by using either annual total compensation for all such employees or another consistently applied compensation measure.

For these purposes, we used total taxable earnings, plus certain non-taxable items, including retirement plan contributions and perquisites, as determined from the payroll records of Westlake and its affiliates providing the services of the Seconded Employees to OpCo for the period from January 1, 2024 through December 31, 2024 (the "Measurement Date"), as our consistently applied compensation measure.

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After identifying the median Seconded Employee as of the Measurement Date, based on the process described above, we calculated 2025 total compensation for the median Seconded Employee and our Chief Executive Officer using the same methodology we used for determining total compensation for 2025 for our NEOs as set forth in the Summary Compensation Table.

Gilson was not our Chief Executive Officer for all of 2024, to determine the Chief Executive Officer's annual total compensation, we included in the table below his base salary as reported in the Summary Compensation Table, annualized as if he had served for the entire year and multiplied by an annualized allocation percentage of 10%.

Chief Executive Officer annual total compensation (A) $ 128,846

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Westlake Chemical Partners GP LLC — —

Chao 175,528 (2)

Chao 13,908 *

Jean-Marc Gilson

Steven Bender 14,000 *

Chao 175,528 (2)

Benjamin Ederington 12,000 *

Stephen Finley

Jean-Marc Gilson

Woelfel 23,913 *

14 unchanged sentences

93,405,554 (2)

Steven Bender 130,159 *

Chao 1,156,775 *

Chao 138,265 *

Jean-Marc Gilson

Steven Bender 97,274 *

Benjamin Ederington 177,887 *

Stephen Finley — —

Jean-Marc Gilson

All current directors and executive officers as a group (10 persons)

13 unchanged sentences

15,524,099 (1)

Energy Income Partners, LLC

10 Wright Street

Westport, CT 06880

2,081,811 (2)

1555 Peachtree Street NE, Suite 1800

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5 to a Schedule 13G filed on February 13, 2024.

According to the filing, Energy Income Partners, LLC had shared voting and shared dispositive power over 2,081,811 common units.

In addition, each of James J.

Murchie, Eva Pao and John K.

Tysseland had shared voting and shared dispositive power over 2,081,811 common units as portfolios managers with respect to the portfolios managed by Energy Income Partners, LLC, and Saul Ballesteros had shared voting and shared dispositive power over 2,081,811 common units as a control person of Energy Income Partners, LLC.

(3) Based on an Amendment No.

5 to a Schedule 13G filed on February 13, 2024.

According to the filing, Invesco Ltd.

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Except as otherwise indicated, the agreements described below became effective on August 4, 2014, concurrent with the closing of the IPO.

For amounts paid by us or Westlake, as applicable, under the agreements described below, see Note 11 to our consolidated financial statements.

For amounts paid by us or Westlake, as applicable, under the agreements described below, see Note 11, "Related Party Transactions," to our Consolidated Financial Statements.

Ethylene Sales Agreement

OpCo and Westlake are parties to the Ethylene Sales Agreement, which has an initial term through December 31, 2026 and automatic 12-month renewal periods until terminated at the end of the initial term or any renewal term on 12-months' notice.

On October 28, 2025, OpCo and Westlake agreed to renew the Ethylene Sales Agreement through December 31, 2027 in accordance with its terms.

The Ethylene Sales Agreement requires Westlake to purchase OpCo's planned ethylene production each year, subject to certain exceptions and a maximum commitment of 3.8 billion pounds per year, less product sold by OpCo to third parties equal to approximately 5% of the annual output.

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This purchase price is not designed to cover capital expenditures for expansion.

Variable costs not incurred by OpCo due to a deficiency in purchases by Westlake are rebated to Westlake.

Under specified circumstances, unrecovered costs may be carried forward for recovery in subsequent years.

Variable costs not incurred by OpCo due to deficiencies in purchases by Westlake are rebated to Westlake.

If OpCo's actual production is in excess of planned ethylene production, Westlake has the option to purchase up to 95% of production in excess of planned production.

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Costs specific to the processing of Westlake's purge gas are recovered under the Services and Secondment Agreement, and not the Ethylene Sales Agreement.

On November 1, 2018, OpCo and Westlake entered into an amendment to the Ethylene Sales Agreement that provides OpCo with the option to curtail up to 5% of its ethylene production annually in the event OpCo reasonably determines that its sales of such ethylene to third parties during the relevant period would be uneconomic.

Under the Ethylene Sales Agreement, OpCo has the option to curtail up to approximately 5% of its ethylene production annually in the event OpCo reasonably determines that its sales of such ethylene to third parties during the relevant period would be uneconomic.

Feedstock Supply Agreement

OpCo and Westlake are parties to the Feedstock Supply Agreement, which has an initial term through December 31, 2026 and automatic 12-month renewal periods until terminated at the end of the initial term or any renewal term on 12-months' notice.

Under the Feedstock Supply Agreement, Westlake agreed to sell OpCo ethane and other feedstock in amounts sufficient for OpCo to produce the ethylene to be sold under the Ethylene Sales Agreement.

On October 28, 2025, OpCo and Westlake agreed to renew the Feedstock Supply Agreement through December 31, 2027 in accordance with its terms.

Under the Feedstock Supply Agreement, Westlake sells OpCo ethane and other feedstock in amounts sufficient for OpCo to produce the ethylene to be sold under the Ethylene Sales Agreement.

The price at which ethane and feedstock is sold includes an indexed price for spot gas liquids at Mont Belvieu and applicable transportation, storage and other costs.

Services and Secondment Agreement

OpCo and Westlake are parties to the Services and Secondment Agreement, pursuant to which OpCo provides Westlake with various utilities and utility services and in exchange for Westlake providing OpCo with various utility services, comprehensive operating services for OpCo's units, services for the maintenance and operation of the common facilities and seconded employees to perform all services required under the agreement.

OpCo and Westlake are parties to the Services and Secondment Agreement, pursuant to which OpCo provides Westlake with various utilities and utility services in exchange for Westlake providing OpCo with various utility services, comprehensive operating services for OpCo's units, services for the maintenance and operation of the common facilities and seconded employees to perform all services required under the agreement.

In connection with the renewals of the Ethylene Sales Agreement and the Feedstock Supply Agreement, on October 28, 2025, OpCo and certain affiliates of Westlake entered into an amendment to the Services and Secondment Agreement to align the date of expiration of such agreement with the date of expiration of the Ethylene Sales Agreement.

Pursuant to the Services and Secondment Agreement, certain subsidiaries of Westlake have agreed to indemnify OpCo for certain liabilities incurred in connection with the performance of Westlake's services under such agreement.

Lease Agreements

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We, OpCo and Westlake are parties to the Omnibus Agreement, pursuant to which we granted Westlake, among other things, a right of first refusal on any proposed transfer of (1) our equity interests in OpCo, (2) the ethylene production facilities that serve Westlake's other facilities or (3) certain other assets we may acquire from Westlake.

The Omnibus Agreement also provides for reimbursement to Westlake for the provision of various administrative and professional services and direct expenses incurred on our behalf and in connection with the operation of our business, including, but not limited to, legal, accounting services, audit services, human resources, insurance, tax, credit, finance, government affairs and regulatory affairs.

Under the Omnibus Agreement, Westlake will indemnify us against certain environmental and other losses, and we will indemnify Westlake against certain environmental and other losses for which Westlake is not otherwise obligated to indemnify us and certain other losses and liabilities to the extent resulting from the provision of services by Westlake to us.

The Omnibus Agreement also provides for reimbursement to Westlake for the provision of various administrative services and direct expenses incurred on our behalf and in connection with the operation of our business, including, but not limited to, legal, accounting services, audit services, human resources, insurance, tax, credit, finance, government affairs and regulatory affairs.

Under the Omnibus Agreement, Westlake will indemnify us against certain environmental and other losses that occurred or existed prior to August 4, 2014, and we will indemnify Westlake against certain environmental and other losses for which Westlake is not otherwise obligated to indemnify us and certain other losses and liabilities to the extent resulting from the provision of services by Westlake to us.

In connection with the renewals of the Ethylene Sales Agreement and the Feedstock Supply Agreement, on October 28, 2025, the Partnership, OpCo and certain affiliates of Westlake entered into an amendment to the Omnibus Agreement to provide that the Omnibus Agreement would terminate upon termination of the Ethylene Sales Agreement.

OpCo Partnership Agreement

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______________________________

(1) Audit fees represent fees billed for professional services rendered for the audits of our annual consolidated financial statements, audit of internal controls and quarterly review of our consolidated financial statements in 2024 and 2023 and review of a registration statement filed with the SEC in 2024 and 2023.

(1) Audit fees represent fees billed for professional services rendered for the audits of our annual consolidated financial statements, audit of internal controls and quarterly review of our consolidated financial statements in 2025 and 2024 and review of a registration statement filed with the SEC in 2024.

(2) Tax fees represent tax services with respect to the preparation of the Partnership's 2024 K-1 and K-3 statements in 2025 and the preparation of the Partnership's 2023 K-1 and K-3 statements in 2024 and tax consulting and compliance services in 2025 and 2024.

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4.1 Description of Securities Registered Pursuant to Section 12 of the Securities Exchange Act of 1934 (incorporated by reference to Exhibit 4.1 to Westlake Chemical Partners' Annual Report on Form 10-K for the year ended December 31, 2019, File No.

4.2 Indenture dated as of January 1, 2006 by and among Westlake Corporation, the potential subsidiary guarantors listed therein and JPMorgan Chase Bank, National Association, as trustee (incorporated by reference to Exhibit 4.1 to Westlake Corporation's Current Report on Form 8-K, filed on January 13, 2006, File No.

4.3 Eighth Supplemental Indenture (including the form of the Notes), dated as of August 10, 2016, among Westlake Corporation, the Guarantors (as defined therein) and The Bank of New York Mellon Trust Company, N.A., as trustee (incorporated by reference to Exhibit 4.2 to Westlake Corporation's Current Report on Form 8-K, filed on August 10, 2016, File No.

4.4 Tenth Supplemental Indenture (including the form of the Notes), dated as of November 29, 2017, among Westlake Corporation, the Subsidiary Guarantors (as defined therein) and The Bank of New York Mellon Trust Company, N.A., as trustee (incorporated by reference to Exhibit 4.2 to Westlake Corporation's Current Report on Form 8-K, filed on November 28, 2017, File No.

4.5 Eleventh Supplemental Indenture (including the form of the Notes), dated as of November 28, 2017, among Westlake Corporation, the Subsidiary Guarantors (as defined therein) and The Bank of New York Mellon Trust Company, N.A., as trustee (incorporated by reference to Exhibit 4.3 to Westlake Corporation's Current Report on Form 8-K, filed on November 28, 2017, File No.

4.6 Twelfth Supplemental Indenture (including the form of the Notes), dated as of July 17, 2019, between Westlake Corporation and The Bank of New York Mellon Trust Company, N.A., as trustee (incorporated by reference to Exhibit 4.2 to Westlake's Current Report on Form 8-K filed on July 17, 2019, File No.

4.7 Thirteenth Supplemental Indenture (including the form of Notes), dated as of June 12, 2020, between Westlake Corporation and The Bank of New Mellon Trust Company, N.A., as trustee (incorporated by reference to Exhibit 4.2 to Westlake Corporation's Current Report on Form 8-K filed on June 12, 2020, File No.

4.8 Fourteenth Supplemental Indenture (including the form of Notes), dated as of August 19, 2021, between Westlake Corporation and The Bank of New Mellon Trust Company, N.A., as trustee (incorporated by reference to Westlake Corporation's Current Report on Form 8-K filed on August 19, 2021, File No.

4.2 Registration Rights Agreement by and among Westlake Chemical Partners LP and the persons named therein, dated as of March 29, 2019 (incorporated by reference to Exhibit 4.1 to Westlake Chemical Partners LP's Current Report on Form 8-K, filed on March 29, 2019, File No.

1 unchanged sentence

001-36567) filed on August 8, 2014).

First Amendment to Omnibus Agreement, dated as of October 28, 2025 (incorporated by reference to Exhibit 10.4 to Westlake Chemical Partners LP's Current Report on Form 8-K (File No.

001-36567) filed on October 30, 2025).

10.2 Services and Secondment Agreement by and among Westlake Chemical OpCo LP, Westlake Management Services, Inc., Westlake Vinyls, Inc., WPT LLC and Westlake Petrochemicals LLC (incorporated by reference to Exhibit 10.2 to Westlake Chemical Partners LP's Current Report on Form 8-K (File No.

001-36567) filed on August 8, 2014).

First Amendment to Services and Secondment Agreement, dated as of October 28, 2025 (incorporated by reference to Exhibit 10.

2 to Westlake Chemical Partners LP's Current Report on Form 8-K (File No.

001-36567) filed on October 30, 2025).

10.3 Feedstock Supply Agreement between Westlake Petrochemicals LLC and Westlake Chemical OpCo LP (incorporated by reference to Exhibit 10.3 to Westlake Chemical Partners LP's Current Report on Form 8-K (File No.

1 unchanged sentence

10.4†† Ethylene Sales Agreement between Westlake Chemical OpCo LP, WPT LLC, Westlake Vinyls, Inc.

and Westlake Petrochemicals LLC (incorporated by reference to Exhibit 10.4 to Westlake Chemical Partners LP's Current Report on Form 8-K (File No.

and Westlake Petrochemicals LLC (incorporated by reference to Exhibit 10.

4 to Westlake Chemical Partners LP's Current Report on Form 8-K (File No.

001-36567) filed on August 8, 2014).

20 unchanged sentences

001-36567) filed on July 15, 2022).

10.9† Westlake Chemical Partners LP Long-Term Incentive Plan (incorporated by reference to Exhibit 10.8 to Westlake Chemical Partners LP's Current Report on Form 8-K (File No.

001-36567) filed on August 8, 2014).

Westlake Chemical Partners LP Long-Term Incentive Plan (as amended and restated effective May 8, 2024) (incorporated by reference to Appendix A to Westlake Chemical Partners LP's Definitive Proxy Statement on Schedule 14A filed on March 18, 2024, File No.

6 unchanged sentences

Equity Distribution Agreement, dated October 4, 2018, by and among Westlake Chemical Partners LP, Westlake Chemical Partners GP LLC, UBS Securities LLC, Barclays Capital Inc., Citigroup Global Markets Inc., Deutsche Bank Securities Inc., Merrill Lynch, Pierce, Fenner & Smith Incorporated, RBC Capital Markets, LLC and Wells Fargo Securities, LLC (incorporated by reference to Exhibit 1.1 to Westlake Chemical Partners LP's Current Report on Form 8-K filed on October 5, 2018, File No.

First Amendment to Equity Distribution Agreement by and among Westlake Chemical Partners LP, Westlake Chemical Partners GP LLC, UBS Securities LLC, Barclays Capital Inc., BofA Securities, Inc., Citigroup Global Markets Inc., Deutsche Bank Securities Inc., RBC Capital Markets, LLC and Wells Fargo Securities, LLC dated as of February 28, 2020 (incorporated by reference to Exhibit 10.22 to Westlake Chemical Partner s LP's Annual Report on Form 10-K for the year ended December 31, 2019, filed on February 28, 2020, File No, 001-36567).

Westlake Ch emical Partners LP Insider Trading Policy .

First Amendment to Equity Distribution Agreement by and among Westlake Chemical Partners LP, Westlake Chemical Partners GP LLC, UBS Securities LLC, Barclays Capital Inc., BofA Securities, Inc., Citigroup Global Markets Inc., Deutsche Bank Securities Inc., RBC Capital Markets, LLC and Wells Fargo Securities, LLC dated as of February 28, 2020 (incorporated by reference to Exhibit 10.22 to Westlake Chemical Partners LP's Annual Report on Form 10-K for the year ended December 31, 2019, filed on February 28, 2020, File No, 001-36567).

Westlake Chemical Partners LP Insider Trading Policy (incorporated by reference to Exhibit 19 to Westlake Chemical Partners LP's Annual Report on Form 10-K for the year ended December 31, 2024, filed on March 5, 2025, File No.

21.1* List of Subsidiaries of Westlake Chemical Partners LP.

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B ENJAMIN E DERINGTON

Executive Vice President, Performance and

Essential Materials, General Counsel, Chief

Administrative Officer and Director

Executive Vice President, Legal and External

Affairs and Director

March 4, 2026

15 unchanged sentences

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-K

Item 9A. Controls and Procedures