Q3 FY19 Financial Results

Footnotes for GAAP to Non-GAAP Reconciliation This presentation contains the following financial measures that are not in accordance with U.S. generally accepted accounting principles ("GAAP"): non-GAAP cost of revenue; non-GAAP gross profit; non-GAAP operating expenses; non-GAAP operating income; non-GAAP interest and other expense, net; non-GAAP income tax expense; non-GAAP net income; non-GAAP diluted income per common share; and non-GAAP gross margin ("Non-GAAP measures"). These Non-GAAP measures are not in accordance with, or an alternative for, measures prepared in accordance with GAAP and may be different from Non-GAAP measures used by other companies. The company believes the presentation of these Non-GAAP measures, when shown in conjunction with the corresponding GAAP measures, provides useful information to investors for measuring the company's earnings performance and comparing it against prior periods. Specifically, the company believes these Non-GAAP measures provide useful information to both management and investors as they exclude certain expenses, gains and losses that the company believes are not indicative of its core operating results or because they are consistent with the financial models and estimates published by many analysts who follow the company and its peers. As discussed further below, these Non-GAAP measures exclude the amortization of acquired intangible assets, stock- based compensation expense, employee termination, asset impairment and other charges, acquisition-related charges, charges related to cost saving initiatives, manufacturing underutilization charges, convertible debt activity, debt extinguishment costs, other adjustments, and income tax adjustments, and the company believes these measures along with the related reconciliations to the GAAP measures provide additional detail and comparability for assessing the company's results. These Non-GAAP measures are some of the primary indicators management uses for assessing the company's performance and planning and forecasting future periods. These measures should be considered in addition to results prepared in accordance with GAAP, but should not be considered a substitute for, or superior to, GAAP results. As described above, the company excludes the following items from its Non-GAAP measures: Amortization of acquired intangible assets. The company incurs expenses from the amortization of acquired intangible assets over their economic lives. Such charges are significantly impacted by the timing and magnitude of the company's acquisitions and any related impairment charges. Stock-based compensation expense. Because of the variety of equity awards used by companies, the varying methodologies for determining stock-based compensation expense, the subjective assumptions involved in those determinations, and the volatility in valuations that can be driven by market conditions outside the company's control, the company believes excluding stock-based compensation expense enhances the ability of management and investors to understand and assess the underlying performance of its business over time and compare it against the company's peers, a majority of whom also exclude stock-based compensation from their non-GAAP results. Employee termination, asset impairment and other charges. From time-to-time, in order to realign the company's operations with anticipated market demand or to achieve cost synergies from the integration of acquisitions, the company may terminate employees and/or restructure its operations. From time-to-time, the company may also incur charges from the impairment of intangible assets and other long-lived assets. These charges (including any reversals of charges recorded in prior periods) are inconsistent in amount and frequency, and the company believes are not indicative of the underlying performance of its business. Acquisition-related charges. In connection with the company's business combinations, the company incurs expenses which it would not have otherwise incurred as part of its business operations. These expenses include third-party professional service and legal fees, third-party integration services, severance costs, non-cash adjustments to the fair value of acquired inventory, contract termination costs, and retention bonuses. The company may also experience other accounting impacts in connection with these transactions. These charges and impacts are related to acquisitions, are inconsistent in amount and frequency, and the company believes are not indicative of the underlying performance of its business. Charges related to cost saving initiatives. In connection with the transformation of the company's business combinations, the company has incurred charges related to cost saving initiatives which do not qualify for special accounting treatment as exit or disposal activities. These charges, which the company believes are not indicative of the underlying performance of its business, primarily relate to costs associated with rationalizing the company's channel partners or vendors, transforming the company's information systems infrastructure, integrating the company's product roadmap, and accelerated depreciation of assets. Manufacturing underutilization charges. In response to the current flash business conditions, the company is reducing its wafer starts at its flash-based memory manufacturing facilities operated through its strategic partnership with Toshiba Memory Corporation (TMC). The temporary abnormal reduction in output has resulted in flash manufacturing underutilization charges which are expensed as incurred. These charges are inconsistent in amount and frequency, and the company believes these charges are not part of the ongoing operation of its business. Convertible debt activity, net. The company excludes non-cash economic interest expense associated with its convertible notes, the gains and losses on the conversion of its convertible senior notes and call option, and unrealized gains and losses related to the change in fair value of the exercise option and call option. These charges and gains and losses do not reflect the company's operating results, and the company believes are not indicative of the underlying performance of its business. Debt extinguishment costs. From time-to-time, the company replaces its existing debt with new financing at more favorable interest rates or utilizes available capital to settle debt early, both of which generate interest savings in future periods. The company incurs debt extinguishment charges consisting of the costs to call the existing debt and/or the write-off of any related unamortized debt issuance costs. These gains and losses do not reflect the company's operating results, and the company believes are not indicative of the underlying performance of its business. Other adjustments. From time-to-time, the company sells or impairs investments or other assets which are not considered necessary to its business operations, or incurs other charges or gains that the company believes are not a part of the ongoing operation of its business. The resulting expense or benefit is inconsistent in amount and frequency. Income tax adjustments. Income tax adjustments include the difference between income taxes based on a forecasted annual non-GAAP tax rate and a forecasted annual GAAP tax rate as a result of the timing of certain non-GAAP pre-tax adjustments. The income tax adjustments include the company's final adjustments for the tax effects of the Tax Cuts and Jobs Act allowed within the one-year measurement period that ended on December 22, 2018, as well as estimates related to the current status of the rules and regulations governing the transition to the Tax Cuts and Jobs Act. These adjustments are excluded because they are infrequent and the company believes that they are not indicative of the underlying performance of its business. Western Digital. ©2019 Western Digital Corporation or its affiliates. All rights reserved. 4/29/19 14