Sec Form 4 Filing - Armstrong Steve @ MSC INDUSTRIAL DIRECT CO INC - 2021-04-08

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 Armstrong Steve 2. Issuer Name and Ticker or Trading Symbol MSC INDUSTRIAL DIRECT CO INC [ MSM] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) SVP, GC and Corp. Secy. (Last) (First) (Middle) C/O MSC INDUSTRIAL DIRECT CO., INC., 75 MAXESS ROAD 3. Date of Earliest Transaction (MM/DD/YY) 04/08/2021 (Street) MELVILLE, NYUS 11747 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 Class A Common Stock, $0.001 par value 04/08/2021 M 16,814 A $ 83.03 25,633 D Class A Common Stock, $0.001 par value 04/08/2021 M 7,227 A $ 83.21 32,860 D Class A Common Stock, $0.001 par value 04/08/2021 M 13,086 A $ 79.6 45,946 D Class A Common Stock, $0.001 par value 04/08/2021 M 2,994 A $ 71.33 48,940 D Class A Common Stock, $0.001 par value 04/08/2021 S 39,739 D $ 90.0104 ( 1 ) 9,201 D Class A Common Stock, $0.001 par value 04/08/2021 S 382 D $ 91.05 8,819 D Class A Common Stock, $0.001 par value 04/09/2021 M 18,223 A $ 58.9 27,042 D Class A Common Stock , $0.001 par value 04/09/2021 S 18,223 D $ 90.0332 ( 2 ) 8,819 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 Options (right to buy) ( 3 ) 04/08/2021 M 16,814 ( 4 ) 10/21/2022 Class A Common Stock, $0.001 par value 16,814 $ 83.03 0 D Options (right to buy) ( 3 ) 04/08/2021 M 7,227 ( 5 ) 10/16/2025 Class A Common Stock, $0.001 par value 7,227 $ 83.21 8,787 D Options (right to buy) ( 3 ) 04/08/2021 M 13,086 ( 6 ) 10/19/2024 Class A Common Stock, $0.001 par value 13,086 $ 79.6 4,362 D Options (right to buy) ( 3 ) 04/08/2021 M 2,994 ( 7 ) 10/25/2023 Class A Common Stock, $0.001 par value 2,994 $ 71.33 18,343 D Options (right to buy) ( 3 ) 04/09/2021 M 18,223 ( 8 ) 10/18/2022 Class A Common Stock, $0.001 par value 18,223 $ 58.9 4,361 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Armstrong Steve C/O MSC INDUSTRIAL DIRECT CO., INC. 75 MAXESS ROAD MELVILLE, NYUS 11747 SVP, GC and Corp. Secy. Signatures /s/ Steve Armstrong 04/12/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents the sale of 39,739 shares in 22 separate transactions, ranging from $90.00 to $90.36 per share, resulting in a weighted average sale price per share of $90.0104. The Reporting Person undertakes to provide upon request by the SEC staff, the Issuer, or a security holder of the Issuer, full information regarding the number of shares sold at each separate price within the range. ( 2 )Represents the sale of 18,223 shares in 29 separate transactions, ranging from $90.00 to $90.21 per share, resulting in a weighted average sale price per share of $90.0332. The Reporting Person undertakes to provide upon request by the SEC staff, the Issuer, or a security holder of the Issuer, full information regarding the number of shares sold at each separate price within the range. ( 3 )Represents options to purchase the Issuer's Class A Common Stock, $0.001 par value ("Common Stock"). ( 4 )An option to purchase 16,814 shares of the Issuer's Common Stock was issued to the Reporting Person under the Issuer's 2005 Omnibus Incentive Plan. 4,203 shares of Common Stock became exercisable on each of October 22, 2015 and October 22, 2016, and 4,204 shares of Common Stock became exercisable on each of October 22, 2017, October 22, 2018. ( 5 )An option to purchase 16,014 shares of the Issuer's Common Stock was issued to the Reporting Person under the Issuer's 2015 Omnibus Incentive Plan. 4,003 shares of Common Stock became exercisable on each of October 17, 2019 and October 17, 2020, and 4,004 shares of common stock become exercisable on each of October 17, 2021, and October 17, 2022. ( 6 )An option to purchase 17,448 shares of the Issuer's Common Stock was issued to the Reporting Person under the Issuer's 2015 Omnibus Incentive Plan. 4,362 shares of Common Stock became exercisable on each of October 20, 2018, October 20, 2019, and October 20, 2020, and 4,362 become exercisable on October 20, 2021. ( 7 )An option to purchase 21,337 shares of the Issuer's Common Stock was issued to the Reporting Person under the Issuer's 2015 Omnibus Incentive Plan. 5,334 shares of Common Stock became exercisable on each of October 26, 2017, October 26, 2018, and October 26, 2019. 5,335 shares of Common Stock became exercisable on October 26, 2020. ( 8 )An option to purchase 22,584 shares of the Issuer's Common Stock was issued to the Reporting Person under the Issuer's 2015 Omnibus Incentive Plan. 5,646 shares of Common Stock became exercisable on each of October 19, 2016, October 19, 2017, October 19, 2018, and October 19, 2019.

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