INCOME TAXES

On December 22, 2017, the Tax Cuts and Jobs Act (the "Tax Act") was enacted. The Tax Act significantly revises the U.S. corporate income tax by, among other things, lowering the statutory corporate income tax rate (“federal 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 that were previously tax deferred. As a fiscal-year taxpayer, certain provisions of the Tax Act impact Ciena in fiscal 2018, including the change in the federal tax rate and the one-time transition tax, while other provisions will be effective at the beginning of fiscal 2019, including the implementation of a modified territorial tax system, other changes to how foreign earnings are subject to U.S. tax, and adoption of an alternative tax system.

As a result of the decrease in the federal tax rate from 35% to 21% effective January 1, 2018, Ciena has computed its income tax expense for the October 31, 2018 fiscal year using a blended federal tax rate of 23.4%. The 21% federal tax rate is expected to apply to Ciena’s fiscal year ending October 31, 2019 and each year thereafter. Ciena remeasured its deferred tax assets and liabilities ("DTA") using the federal tax rate that will apply when the related temporary differences are expected to reverse.

During the six months ended April 30, 2018, Ciena recorded a provisional tax expense of $484.4 million, primarily related to the Tax Act and consisted of the following: a $431.3 million charge related to the remeasurement of U.S. net deferred tax assets at the lower statutory rate under the Tax Act and a $45.6 million charge related to a transition tax on accumulated historical foreign earnings and its deemed repatriation to the U.S.

In December 2017, the SEC issued Staff Accounting Bulletin No. 118, which addresses how a company recognizes provisional amounts when it does not have the necessary information available, prepared or analyzed (including computations) in reasonable detail to complete its accounting for the effect of the changes due to the Tax Act. The measurement period ends when a company has obtained, prepared and analyzed the information necessary to finalize its accounting, but cannot extend beyond one year. The final impact of the Tax Act may differ from the above provisional amounts due to changes in interpretations of the Tax Act, legislative action to address questions that arise because of the Tax Act, changes in accounting standards for income taxes and related interpretations in response to the Tax Act, and any updates or changes to estimates used in the provisional amounts. Ciena has determined that the $45.6 million of tax expense for the U.S. transition tax on accumulated earnings of foreign subsidiaries and the $431.3 million of tax expense for DTA remeasurement were each provisional amounts and reasonable estimates as of April 30, 2018. Estimates used in the provisional amounts include the anticipated reversal pattern of the gross DTA plus the earnings and profits, cash position at the end of fiscal year 2018, foreign taxes and withholding taxes attributable to foreign subsidiaries.

Ciena currently intends to reinvest indefinitely its foreign earnings outside the U.S. However, Ciena intends to further study changes enacted by the Tax Act, costs of repatriation and the current and future cash needs of foreign operations to determine whether there is an opportunity to repatriate these earnings in the future on a tax-efficient basis. If Ciena determines to repatriate these earnings, the provisional amount of unrecognized deferred income tax liability related to these foreign withholding taxes would be approximately $24.0 million. There are no other significant temporary differences for which a deferred tax liability has not been recognized.

The significant components of DTA are as follows (in thousands):



	April 30,			October 31,
	2018			2017
Deferred tax assets:
Reserves and accrued liabilities	$	36,115		$	56,597
Depreciation and amortization	288,145			451,385
NOL and credit carry forward	538,869			803,622
Other	18,706			29,398
Gross deferred tax assets	881,835			1,341,002
Valuation allowance	(147,011		)	(185,898		)
Deferred tax asset, net of valuation allowance	$	734,824		$	1,155,104

In connection with the adoption of ASU 2016-09, Ciena recognized approximately $62.1 million of deferred tax assets related to previously unrecognized tax benefits. This was recorded as a cumulative-effect adjustment to retained earnings as of the beginning of the first quarter of fiscal 2018. See Note 2 above and Note 14 below. As of April 30, 2018, Ciena continues to maintain a valuation allowance of $147.0 million. This valuation allowance is primarily related to state and foreign net operating losses and credits that Ciena estimates it will not be able to use.