Income Taxes

6 Months Ended

Nov. 30, 2021

Income Tax Disclosure [Abstract]

Income Taxes

NOTE 5 — INCOME TAXES

The effective tax rate was 11.0% and 12.7% for the six months ended November 30, 2021 and 2020, respectively. The decrease in the Company's effective tax rate was primarily due to a more favorable impact from stock-based compensation and discrete items such as the recognition of a reserve in the first quarter of fiscal 2021 related to Altera Corp. v. Commissioner. The decrease in the Company's effective tax rate was partially offset by a change in the Company's earnings mix.

As of November 30, 2021, total gross unrecognized tax benefits, excluding related interest and penalties, were $926 million, $651 million of which would affect the Company's effective tax rate if recognized in future periods. The majority of the total gross unrecognized tax benefits are long-term in nature and included within Deferred income taxes and other liabilities on the Unaudited Condensed Consolidated Balance Sheets. As of May 31, 2021, total gross unrecognized tax benefits, excluding related interest and penalties, were $896 million. The liability for payment of interest and penalties increased by $23 million during the six months ended November 30, 2021. As of November 30, 2021 and May 31, 2021, accrued interest and penalties related to uncertain tax positions were $226 million and $203 million, respectively (excluding federal benefit).

The Company is subject to taxation in the United States, as well as various state and foreign jurisdictions. The Company is currently under audit by the U.S. Internal Revenue Service ("IRS") for fiscal years 2017 through 2019. The Company has closed all U.S. federal income tax matters through fiscal 2016, with the exception of certain transfer pricing adjustments.

Tax years after 2010 remain open in certain major foreign jurisdictions. Although the timing of resolution of audits is not certain, the Company evaluates all domestic and foreign audit issues in the aggregate, along with the expiration of applicable statutes of limitations, and estimates that it is reasonably possible the total gross unrecognized tax benefits could decrease by up to $20 million within the next 12 months. In January 2019, the European Commission opened a formal investigation to examine whether the Netherlands has breached State Aid rules when granting certain tax rulings to the Company. The Company believes the investigation is without merit. If this matter is adversely resolved, the Netherlands may be required to assess additional amounts with respect to prior periods, and the Company's income taxes related to prior periods in the Netherlands could increase.