2018 Guide to Effective Proxies

6 TH EDITION | GUIDE TO EFFECTIVE PROXIES 432 MCKESSON CORPORATION EXECUTIVE COMPENSATION Five-Year Total Shareholder Return of 35%, CEO Pay Down 30% From the end of FY 2013 through the end of FY 2018, McKesson delivered total shareholder return of 35%, while the Compensation Committee’s decisions and cumulative changes to our executive compensation program reduced the CEO’s total compensation over the same period by 30%, as disclosed in the Summary Compensation Table (“SCT”) in the Company’s proxy statements. Total Shareholder Return (1) vs. CEO Total SCT Compensation $25.9M $24.8M $23.6M $20.1M $18.1M SCT Pay $165 $212 $148 $141 $135 McKesson TSR $0 $100 $200 TSR in $ 2013 2014 2015 2016 2017 2018 (1) Total shareholder return (“TSR”) assumes $100 invested at the close of trading on March 28, 2013, the last trading day of FY 2013, and the reinvestment of dividends. CEO Realizable Pay The ultimate value our CEO actually realizes from long-term incentives is based entirely on the value of McKesson shares and the Company’s financial and operational performance. Due to the strong alignment between pay and performance over the last three years, our CEO’s total realizable pay is 44% lower than the values disclosed in the SCT for FY 2016 through FY 2018, and the realizable pay with respect to our CEO’s long-term incentives alone is 62% lower than the values disclosed in the SCT for FY 2016 through FY 2018. Three-Year Total CEO Disclosed Pay vs. Three-Year Total Realizable Pay (1) $0 $13,000 $26,000 $39,000 $52,000 $65,000 FY 2016 — FY 2018 Disclosed Pay FY 2016 — FY 2018 Realizable Pay – $27.5 Million (– 44%) $61,889 $34,383 ($ in000’s) Stock Options $15,375 $0 PSUs $20,582 $10,191 Cash LTIP $8,205 $6,466 Base + MIP $16,153 $16,153 All Other $1,574 $1,574 Total $34,383 $61,889 FY 2016 — FY 2018 Disclosed Pay FY 2016 — FY 2018 Realizable Pay ($ in 000’s) (1) For this purpose, “Realizable Pay” is defined as the sum of: (i) actual base salary and annual incentives paid for the three-year period; (ii) the intrinsic value (i.e., the excess, if any, of the closing price of our common stock as reported by the NYSE on March 29, 2018, the last trading day of our FY 2018, over the option exercise price) of all stock options granted during the three-year period; (iii) the actual payout value of PSU and Cash LTIP awards granted in FY 2016; and (iv) target Cash LTIP awards granted in FY 2017 and FY 2018 and target PSUs granted in FY 2017 and FY 2018, calculated using $140.87, the closing price of our common stock as reported by the NYSE on March 29, 2018. - 2018 Proxy Statement 35