Stockholders' Equity and Per Share Data

Our certificate of incorporation authorizes 10,020,000,000 shares of capital stock as follows:


•	9,000,000,000 shares of common stock, par value $0.01 per share;


•	1,000,000,000 shares of non-voting common stock, par value $0.01 per share; and


•	20,000,000 shares of preferred stock, par value $0.0001 per share.

Classes of Common Stock

Voting Common Stock

The holders of our common stock are entitled to one vote per share on all matters submitted for action by the stockholders. There were approximately 4.0 billion shares of common stock outstanding as of March 31, 2018.

Treasury Shares

Shares of common stock repurchased by us are recorded at cost as treasury shares and result in a reduction of stockholders' equity. We reissue treasury shares as part of our stockholder approved stock-based compensation programs, as well as upon conversion of outstanding securities that are convertible into common stock. When shares are reissued, we determine the cost using the FIFO method.

Dividends

We did not declare any dividends on our common shares for all periods presented in the consolidated financial statements. We are currently restricted from paying cash dividends by the terms of our secured revolving bank credit facility (see Note 7. Long-Term Debt, Financing and Capital Lease Obligations).

Accumulated Other Comprehensive Loss

The components of accumulated other comprehensive loss, net of tax were as follows:



	March 31,
	2018			2017
	(in millions)
Unrecognized net periodic pension and postretirement benefit cost	$	(337	)	$	(369	)
Unrealized net gains related to investments	8			—
Unrealized net gain (losses) on derivatives	32			(2		)
Foreign currency translation adjustments	(16		)	(33		)
Accumulated other comprehensive loss	$	(313	)	$	(404	)

Per Share Data

Basic net income (loss) per common share is calculated by dividing net income (loss) by the weighted average number of common shares outstanding during the period. Diluted net income (loss) per common share adjusts basic net income (loss) per common share, computed using the treasury stock method, for the effects of potentially dilutive common shares, if the effect is not antidilutive. As of the year ended March 31, 2018, the computation of diluted net income (loss) per common share includes the effect of dilutive securities consisting of approximately 61 million options and restricted stock units, in addition to 18 million shares attributable to warrants, of which 14 million relate to the warrant held by SoftBank. Outstanding options to purchase shares totaling 6 million were not included in the computation of diluted net income (loss) per common share because to do so would have been antidilutive. Outstanding options and restricted stock units (exclusive of participating securities) that had no effect on our computation of dilutive weighted average number of shares outstanding as their effect would have been antidilutive were approximately 114 million and 73 million as of the years ended March 31, 2017 and 2016, respectively, in addition to 62 million total shares issuable under warrants, of which 55 million relate to shares issuable under the warrant held by SoftBank. The warrant was issued to SoftBank at the close of the merger with SoftBank and is exercisable at $5.25 per share at the option of Softbank, in whole or in part, at any time on or prior to July 10, 2018.