Sec Form 4 Filing - Chiang Willie CW @ PLAINS ALL AMERICAN PIPELINE LP - 2024-08-14

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Chiang Willie CW 2. Issuer Name and Ticker or Trading Symbol PLAINS ALL AMERICAN PIPELINE LP [ PAA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chairman & CEO (Last) (First) (Middle) 333 CLAY STREET, SUITE 1600 3. Date of Earliest Transaction (MM/DD/YY) 08/14/2024 (Street) HOUSTON, TX77002 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Units 08/14/2024 M 418,585 A $ 0 1,011,226 D Common Units 08/14/2024 F 164,714 D $ 17.05 846,512 D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Phantom Units ( 1 ) ( 2 ) 08/14/2024 M 418,585 08/14/2024 08/14/2024 Common Units 418,585 $ 0 0 D Phantom Units ( 1 ) ( 2 ) 08/15/2024 A 357,750 ( 3 )( 4 )( 5 ) ( 3 )( 4 )( 5 ) Common Units 357,750 $ 0 357,750 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Chiang Willie CW 333 CLAY STREET SUITE 1600 HOUSTON, TX77002 X Chairman & CEO Signatures /s/ Ann F. Gullion, as attorney-in-fact for Willie CW Chiang 08/16/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Phantom Units granted under Long-Term Incentive Plan (includes distribution equivalent rights payable in cash). ( 2 )One common unit is deliverable, upon vesting, for each Phantom Unit that vests. ( 3 )These phantom units will vest as follows: (a) Tranche 1, consisting of 178,875 phantom units, will vest on the August 2027 distribution date assuming continued service through such date; (b) Tranche 2, consisting of 89,437 phantom units (assuming 100% payout at target), will potentially vest on the August 2027 distribution date at a scaled payout range of between 0% to 200% based on PAA's total shareholder return (TSR) over the three-year period ending June 30, 2027 compared to the TSR of a selected peer group (payout based on numeric rank with 100% earned at median and interpolation between ranks, and with payout being subject to reduction by up to 25 basis points, but not below 100%, if actual TSR is negative); and ( 4 )(c) Tranche 3, consisting of 89,438 phantom units (assuming 100% payout at target), will potentially vest on the Aug. 2027 distribution date at a scaled payout range of between 0% and 200% based on PAA achieving cumul. distributable cash flow (DCF) per common unit equivalent (CUE) of $7.75 over the 3-year period ending 6/30/27 (with payout equaling 100% at cumul. DCF/CUE over such period of $7.75 and being equal to 0% for cumul. DCF/CUE over such period of $6.975 or lower and 200% for cumul. DCF/CUE over such period of $8.71875 or higher, with interpolation btw. such points, and with payout being subject to reduction by 25 basis pts. if PAA's leverage ratio (long term debt to adj. EBITDA as calculated pursuant to PAA's sr. unsecured revolving credit facility) as of 6/30/27 is greater than the leverage ratio that equals the upper end of our then applicable target leverage ratio range (e.g., 3.0x is the upper end of PAA's current target leverage ratio range of 2.5x to 3.0x). ( 5 )DERs associated with Tranche 1 will accrue for the first year and be paid in cash in a lump sum on the August 2025 distribution date; beginning in November 2025, DERs associated with Tranche 1 will be paid quarterly until the phantom units vest or terminate. DERs associated with Tranches 2 and 3 will accrue during the three-year vesting period and be paid in cash in a lump sum on the August 2027 distribution date with respect to each phantom unit that vests, if any, on such date. Any Tranche 2 or Tranche 3 phantom units that are determined to not have vested as of the August 2027 distribution date shall expire as of such date.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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