ITEM 1. McHenry, Illinois 1. Committees: 1, 2 COMMITTEES 1.

ITEM 1. Patterson, certify that: 1. Committee: 2 COMMITTEES 1.

Version / Date: 1 (no adjustments) / 30.12.2024 Page 1 of 2 ISCC PLUS Certificate Certificate Number: ISCC-PLUS-Cert-PL214-26100824 Bureau Veritas Polska Sp. z o.o. Version / Date: 1 (no adjustments) / 30.12.2024 Page 2 of 2 Annex I to the certificate: Sustainable materials handled by the certified site (This annex is applicable for all scopes except of Trader, Trader with storage, Warehouse, Logistic centres, MTBE and ETBE) This annex is only valid in connection with the certificate: ISCC-PLUS-Cert-PL214-26100824 issued on 30.12.2024 Input material Output material Add-ons (voluntary)1) Raw material category2) SAI FSA3) FEFAC4) Polypropylene (PP) Plastic Compounds (PP) NO Bio Bio-circular Circular N/A N/A Polyethylene (PE) Plastic Compounds (PE) NO Bio Bio-circular Circular N/A N/A 1) ISCC PLUS add-ons (voluntary application, see www.iscc-system.org for further information): • 202-04: Food Security Standard • 205-02: Consumables • 202-07: Low ILUC-risk feedstock • 205-03: Non GMO for food and feed • 205-01: GHG emission requirements • 205-04: Non GMO for technical markets 2) Bio raw materials complies with the ISCC Principles 1 – 6 for the cultivation and harvesting of sustainable biomass.

Birmingham, Alabama 1. Interest on the 2030 Notes is payable semi-annually in arrears on February 1 and August 1 of each year, commencing on February 1, 2023. Beggs, certify that: 1.

Global Policy on Anti-Bribery & Anti-Corruption Issued July 1, 2020 Table of Contents Our Global Policy on Anti-Bribery and Anti-Corruption 1 Importance of Compliance 1 Our Responsibility 1 What Is a Bribe? Violations can result in damage to Avient’s reputation, severe penalties and jail time. 1 Refer to the Gifts and Hospitality section of the Avient Code of Conduct and our Gifts and Entertainment Policy to determine if your proposed expenditure is permitted. This prohibition applies whether the offer or payment is made directly or through another person x Make misleading, incomplete, or false entries in Avient’s books and records x Ignore red flags when dealing with third parties North America Global Headquarters Avon Lake, United States 33587 Walker Road Avon Lake, OH, United States 44012 Toll Free: +1 866 765 9663 Phone: +1 440 930 1000 Fax: +440 930 3064 Asia Pacific Regional Headquarters Shanghai, China 2F, Block C 200 Jinsu Road Pudong, 201206 Shanghai, China Telephone: +86 (0) 21 6028 4888 Fax: +86 (0) 21 6028 4999 South America Sao Paulo, Brazil Av.

Az Avient globális vesztegetésellenes és korrupcióellenes irányelve Kiadva: 2020. július 1. Globális vesztegetésellenes és korrupcióellenes irányelvünk 1 A megfelelés fontossága 1 Felelősségünk 1 Mi tekinthető vesztegetésnek? Észak-Amerika Globális Központ Avon Lake, Egyesült Államok 33587 Walker Road Avon Lake, OH, Egyesült Államok 44012 Ingyenesen hívható telefonszám: +1 866 765 9663 Telefon: +1 440 930 1000 Fax: +440 930 3064 Ázsia és a Csendes-óceáni térség Regionális Központ Sanghaj, Kína 2F, Block C 200 Jinsu Road Pudong, 201206 Sanghaj, Kína Telefonszám: +86 (0) 21 6028 4888 Fax: +86 (0) 21 6028 4999 Dél-Amerika Regionális központ São Paulo, Brazília Av.

Certification structure: MULTI-SITE Certification Date: 29 SEP 2023 Effective Date: 27 FEB 2025 Expiration Date: 27 SEP 2026 Revision Date: 05 MAR 2025 Dominic Townsend, President Page 1 of 5 Avon Lake Corporate Responsible Care Corporate Support Activities in Sr. Mariana Langiewicza 50, 95- 050 Konstantynow, Poland Avient Corporation - Korachi, Sindh Pakistan Design and Manufacture of Colour and Additive Concentrates, 1-A/1, Sector-20 , 74900 Korachi, Pakistan Avient Corporation Design and Manufacture of colour and additive concentrates, thermoplastic resins and specialty compounds Hohenrhein 1 Lahnstein Rheinland- Pfalz 5612 Germany Avient Corporation Design & Manufacturing of Colour and Additive Concentrates. Ezcabarte calle H Nº3 , 31194 Oricain, Spain Avient Corporation Design and Manufacture of Colorants and Additives for Plastics 700/848 Moo 1,Tambol Phan Thong, Amata City Chonburi Industrial Estate Phan Thong Chonburi 20160, Thailand Via Lainate 26, 20005 Pogliano Milanese, Italy Avient Corporation Manufacture of Masterbatches 329 Tungsten Rd, Strydompark , 2194 Randburg, South Africa PolyOne Polymers India Private Limited Design & Manufacture of Color, Additive Concentrate & Specialty Survey No.344/1-2-3, Rania Works, Sakarda Bhadarwa Road Rania Gujarat 391780 India Avient Corporation Design and Manufacture of Color and Additive Concentrates, Thermoplastic Resins and Specialty Compounds 2nd Industrial City, Al-Kharj Road , 11432 Riyadh, Saudi Arabia Crta.

The company noted that first quarter 2025 GAAP EPS includes special items of $0.82 primarily related to an impairment associated with ceasing the development of S/4HANA, a cloud-based ERP system (see attachment 3), and $0.16 of intangible amortization expense (see attachment 1). You are advised to consult any further disclosures we make on related subjects in our reports on Form 10-Q, 8-K and 10-K that we provide to the Securities and Exchange Commission. 5 Investor Relations Contact: Giuseppe (Joe) Di Salvo Vice President, Treasurer and Investor Relations Avient Corporation +1 440-930-1921 giuseppe.disalvo@avient.com Media Contact: Kyle G. Rose Vice President, Corporate Communications Avient Corporation +1 440-930-3162 kyle.rose@avient.com 6 Attachment 1 Avient Corporation Reconciliation of Adjusted Net Income and Earnings Per Share (Unaudited) (In millions, except per share data) Senior management uses comparisons of adjusted net income attributable to Avient common shareholders and diluted adjusted earnings per share (EPS) attributable to Avient common shareholders, excluding special items, to assess performance and facilitate comparability of results.

Identifier Risk 1 Where in the value chain does the risk driver occur? Row 1 Has there been a structural change? Purchased feedstock Percentage of Scope 3, Category 1 tCO2e from purchased feedstock Explain calculation methodology Carbon black 1 Purchased carbon black data was obtained in weight.

Pro Forma Financial Information The Company acquired Avient Protective Materials (“Dyneema”) on September 1, 2022 (the “Acquisition Date”) and sold the Distribution segment on November 1, 2022. To provide comparable results, the company references “pro forma” financial metrics, which include the business results of Avient Protective Materials for periods prior to the Acquisition Date, as if the transaction occurred on January 1, 2021 and reflect Distribution as a discontinued operation. A reconciliation of these measures to their most directly comparable GAAP measures is provided in the tables below. 2023 2022 Reconciliation to Condensed Consolidated Statements of Income $ EPS(1) $ EPS(1) Net income (loss) from continuing operations attributable to Avient shareholders $ 27.8 $ 0.30 $ (17.0) $ (0.19) Special items, after tax (Attachment 3) 5.4 0.06 38.3 0.42 Amortization expense, after-tax 15.0 0.16 14.6 0.16 Adjusted net income / EPS $ 48.2 $ 0.52 $ 35.9 $ 0.39 (1) Per share amounts may not recalculate from figures presented herein due to rounding 2023 2022 Reconciliation to Condensed Consolidated Statements of Income $ EPS(1) $ EPS(1) Net income from continuing operations attributable to Avient shareholders $ 75.8 $ 0.83 $ 82.8 $ 0.90 Special items, after tax (Attachment 3) 79.3 0.86 116.2 1.26 Amortization expense, after-tax 61.5 0.67 49.0 0.53 Adjusted net income / EPS $ 216.6 $ 2.36 $ 248.0 $ 2.69 (1) Per share amounts may not recalculate from figures presented herein due to rounding 1 Reconciliation to EBITDA and Pro Forma Adjusted EBITDA 2023 2022 2023 2022 Sales - GAAP $ 719.0 $ 790.4 $ 3,142.8 $ 3,396.9 Pro forma APM adjustments — — — 256.1 Pro forma adjusted sales $ 719.0 $ 790.4 $ 3,142.8 $ 3,653.0 Net income (loss) from continuing operations – GAAP $ 27.6 $ (16.6) $ 76.3 $ 83.1 Income tax (benefit) expense (7.0) (60.8) 11.0 (19.3) Interest expense 26.8 49.4 115.3 119.8 Depreciation and amortization from continuing operations 44.2 48.6 188.8 162.5 EBITDA from continuing operations $ 91.6 $ 20.6 $ 391.4 $ 346.1 Special items, before tax 22.4 104.3 114.6 194.0 Interest expense included in special items (0.1) (16.0) (2.3) (26.0) Depreciation and amortization included in special items — (1.5) (1.9) (5.5) Adjusted EBITDA $ 113.9 $ 107.4 $ 501.8 $ 508.6 APM pro forma adjustments - 8 months 2022* — — — 83.1 Pro forma adjusted EBITDA $ 113.9 $ 107.4 $ 501.8 $ 591.7 Pro forma adjusted EBITDA as a percent of sales 15.8 % 13.6 % 16.0 % 16.2 % * Pro forma adjustment for January - August 2022 APM results (period before Avient ownership).