X0306 4 2018-01-16 0001003078 MSC INDUSTRIAL DIRECT CO INC MSM 0001447935 Armstrong Steve C/O MSC INDUSTRIAL DIRECT CO., INC. 75 MAXESS ROAD MELVILLE NY US 11747 0 1 0 0 SVP, GC and Corp. Secy. Class A Common Stock, $0.001 par value 2018-01-16 4 M 0 1681 66.69 A 13432 D Class A Common Stock, $0.001 par value 2018-01-16 4 M 0 2040 81.76 A 15472 D Class A Common Stock, $0.001 par value 2018-01-16 4 M 0 15441 69.46 A 30913 D Class A Common Stock, $0.001 par value 2018-01-16 4 S 0 19162 94.98 D 11751 D Options (right to buy) 66.69 2018-01-16 4 M 0 1681 0 D 2018-10-20 Class A Common Stock, $0.001 par value 1681 0 D Options (right to buy) 81.76 2018-01-16 4 M 0 2040 0 D 2020-10-22 Class A Common Stock, $0.001 par value 2040 13741 D Options (right to buy) 69.46 2018-01-16 4 M 0 15441 0 D 2019-10-23 Class A Common Stock, $0.001 par value 15441 0 D Represents the sale of 19,162 shares in 43 separate transactions, ranging from $94.54 to $95.25 per share, resulting in a weighted average sale price per share of $94.9761. 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. Represents options to purchase the Issuer's Class A Common Stock, $0.001 par value ("Common Stock"). An option to purchase 13,379 shares of the Issuer's Common Stock was issued to the Reporting Person under the Issuer's 2005 Omnibus Incentive Plan. 3,344 shares of Common Stock became exercisable on October 21, 2012, and 3,345 became exercisable on each of October 21, 2013, October 21, 2014, and October 21, 2015. An option to purchase 15,781 shares of the Issuer's Common Stock was issued to the Reporting Person under the Issuer's 2005 Omnibus Incentive Plan. 3,945 shares of Common Stock became exercisable on each of October 23, 2014, October 23, 2015, and October 23, 2016, and 3,946 became exercisable on October 23, 2017. An option to purchase 15,441 shares of the Issuer's Common Stock was issued to the Reporting Person under the Issuer's 2005 Omnibus Incentive Plan. 3,860 shares of Common Stock became exercisable on each of October 24, 2013, October 24, 2014, and October 24, 2015, and 3,861 became exercisable on October 24, 2016. /s/ Steve Armstrong 2018-01-17