Income Taxes

6 Months Ended

Apr. 30, 2019

Income Tax Disclosure [Abstract]

Income Taxes

INCOME TAXES

On December 22, 2017, the Tax Cuts and Jobs Act (the "Tax Act") was enacted. The Tax Act significantly revised the U.S. corporate income tax laws by, among other things, lowering the statutory corporate income tax rate from 35% to 21% effective January 1, 2018, implementing a modified territorial tax system, and imposing a mandatory one-time transition tax on accumulated earnings of foreign subsidiaries. The enactment of the Tax Act resulted in Ciena recording a provisional tax expense of $472.8 million in fiscal 2018.

The effective tax rate for the second quarter and six months ended April 30, 2019 was lower than the effective tax rate for the second quarter and six months ended April 30, 2018, primarily due to the impact of the Tax Act. The reduction of the U.S. federal corporate income tax rate from 35% to 21% effective January 1, 2018, required the remeasurement of the net deferred tax assets and liabilities (“DTA”). Also, Ciena recorded U.S. transition tax in the six months ended April 30, 2018.