Unit-Based Compensation

12 Months Ended

Dec. 31, 2017

The Partnership has issued phantom units to its employees and non-employee directors, which vest 60% after three years and 40% after five years. Phantom units have the right to receive distributions prior to vesting. The fair value of these units is the market price of our common units on the grant date, and is amortized over the five-year vesting period using the straight-line method. Unit-based compensation expense related to the Partnership included in our Consolidated Statements of Operations and Comprehensive Income was $24 million, $13 million and $8 million for the years ended December 31, 2017, 2016 and 2015, respectively. The total fair value of phantom units vested for the years ended December 31, 2017, 2016 and 2015, was $9 million, $0 million and $0 million, respectively, based on the market price of SUN’s common units as of the vesting date. Unrecognized compensation expenses related to our nonvested phantom units totaled $27 million as of December 31, 2017, which are expected to be recognized over a weighted average period of 3.7 years. The fair value of nonvested phantom units outstanding as of December 31, 2017 and December 31, 2016, totaled $57 million and $69 million, respectively.

Phantom unit award activity for the years ended December 31, 2017 and December 31, 2016 consisted of the following:



	Number of Phantom Common Units		Weighted-Average Grant Date Fair Value
Outstanding at December 31, 2015	1,147,048		$	41.19
Granted	966,337		26.95
Vested	(1,240	)	36.98
Forfeited	(98,511	)	39.77
Outstanding at December 31, 2016	2,013,634		34.43
Granted	203,867		28.31
Vested	(289,377	)	45.48
Forfeited	(150,823	)	34.71
Outstanding at December 31, 2017	1,777,301		$	31.89

The Partnership previously granted cash restricted units, which vested in cash. As of December 31, 2017, no such awards remained outstanding.