McKesson 2010 Annual Report Download - page 48

McKESSON CORPORATION
FINANCIAL REVIEW (Continued)
42
Income Taxes: Our income tax expense and deferred tax assets and liabilities reflect management’s best
assessment of estimated current and future taxes to be paid. We are subject to income taxes in the U.S. and
numerous foreign jurisdictions. Significant judgments and estimates are required in determining the consolidated
income tax provision and in evaluating income tax uncertainties. We review our tax positions at the end of each
quarter and adjust the balances as new information becomes available.
Deferred income taxes arise from temporary differences between the tax and financial statement recognition of
revenue and expense. In evaluating our ability to recover our deferred tax assets, we consider all available positive
and negative evidence including our past operating results, the existence of cumulative net operating losses in the
most recent years and our forecast of future taxable income. In estimating future taxable income, we develop
assumptions including the amount of future federal, state and foreign pre-tax operating income, the reversal of
temporary differences and the implementation of feasible and prudent tax planning strategies. These assumptions
require significant judgment about the forecasts of future taxable income and are consistent with the plans and
estimates we use to manage the underlying businesses. We had deferred income tax assets (net of valuation
allowances) of $1,187 million and $1,447 million at March 31, 2010 and 2009 and deferred tax liabilities of
$1,845 million and $1,889 million. Deferred tax assets primarily consist of net loss and credit carryforwards and
timing differences on our compensation and benefit related accruals. Deferred tax liabilities primarily consist of
basis differences for inventory valuation (including inventory valued at LIFO) and other assets. We established
valuation allowances of $97 million against certain deferred tax assets, which primarily relate to federal, state and
foreign loss carryforwards for which the ultimate realization of future benefits is uncertain. Changes in tax laws and
rates could also affect recorded deferred tax assets and liabilities in the future. Should tax laws change, including
those laws pertaining to LIFO, our cash flows could be materially impacted.
If our assumptions and estimates described above were to change, an increase/decrease of 1% in our effective
tax rate as applied to income from continuing operations would have increased/decreased tax expense by
approximately $19 million, or $0.07 per diluted share, for 2010.
Share-Based Compensation: Our compensation programs include share-based compensation. We account for
all share-based compensation transactions using a fair-value based measurement method. The share-based
compensation expense is recognized, for the portion of the awards that is ultimately expected to vest, on a straight-
line basis over the requisite service period for those awards with graded vesting and service conditions. For awards
with performance conditions and multiple vest dates, we recognize the expense on a graded vesting basis. For
awards with performance conditions and a single vest date, we recognize the expense on a straight-line basis.
We estimate the grant-date fair value of employee stock options using the Black-Scholes options-pricing model.
We believe that it is difficult to accurately measure the value of an employee stock option. Our estimates of
employee stock option values rely on estimates of factors we input into the model. The key factors involve an
estimate of future uncertain events. The key factors influencing the estimation process, among others, are the
expected life of the option, the expected stock price volatility factor and the expected dividend yield. In determining
the expected life of the option, we primarily use historical experience as our best estimate of future exercise patterns.
We use a combination of historical and implied market volatility to determine the expected stock price volatility
factor. We believe that this market-based input provides a better estimate of our future stock price movements and
is consistent with employee stock option valuation considerations. Once the fair values of employee stock options
are determined, current accounting practices do not permit them to be changed, even if the estimates used are
different from actual experience.