Benefit Plans

Stock Plans

The Company had 273.4 million shares reserved for future issuance under its stock plans as of December 30, 2017. RSUs granted generally vest over four years, based on continued employment, and are settled upon vesting in shares of the Company’s common stock on a one-for-one basis. Each share issued with respect to RSUs granted under the Company’s stock plans reduces the number of shares available for grant under the plan by two shares. RSUs canceled and shares withheld to satisfy tax withholding obligations increase the number of shares available for grant under the plans utilizing a factor of two times the number of RSUs canceled or shares withheld.

Rule 10b5-1 Trading Plans

During the three months ended December 30, 2017, Section 16 officers Angela Ahrendts, Timothy D. Cook, Luca Maestri, Daniel Riccio and Philip Schiller had equity trading plans in place in accordance with Rule 10b5-1(c)(1) under the Exchange Act. An equity trading plan is a written document that pre-establishes the amounts, prices and dates (or formula for determining the amounts, prices and dates) of future purchases or sales of the Company’s stock, including shares acquired pursuant to the Company’s employee and director equity plans.

Restricted Stock Units

A summary of the Company’s RSU activity and related information for the three months ended December 30, 2017 is as follows:



	Number of RSUs (in thousands)		Weighted-Average Grant Date Fair Value Per Share		Aggregate Fair Value (in millions)
Balance as of September 30, 2017	97,571		$	110.33
RSUs granted	35,853		$	157.49
RSUs vested	(19,741	)	$	102.40
RSUs canceled	(1,316	)	$	121.76
Balance as of December 30, 2017	112,367		$	126.64	$	19,016

The fair value as of the respective vesting dates of RSUs was $3.1 billion and $2.2 billion for the three months ended December 30, 2017 and December 31, 2016, respectively.

Share-Based Compensation

The following table shows a summary of the share-based compensation expense included in the Condensed Consolidated Statements of Operations for the three months ended December 30, 2017 and December 31, 2016 (in millions):



	Three Months Ended
	December 30, 2017		December 31, 2016
Cost of sales	$	252	$	229
Research and development	646		589
Selling, general and administrative	398		438
Total share-based compensation expense	$	1,296	$	1,256

The income tax benefit related to share-based compensation expense was $631 million and $465 million for the three months ended December 30, 2017 and December 31, 2016, respectively. As of December 30, 2017, the total unrecognized compensation cost related to outstanding RSUs, restricted stock and stock options was $12.1 billion, which the Company expects to recognize over a weighted-average period of 2.9 years.