|NRG ENERGY, INC. filed this Form 10-K on 02/29/2016|
The fair value of MSUs is estimated on the date of grant using a Monte Carlo simulation model and expensed over the service period, which equals the vesting period. Significant assumptions used in the fair value model with respect to the Company's MSUs are summarized below:
For the years ended December 31, 2015, and 2014, expected volatility is calculated based on NRG's historical stock price volatility data over the period commensurate with the expected term of the MSU, which equals the vesting period.
The following table summarizes NRG's total compensation expense recognized for the years presented as well as total non-vested compensation costs not yet recognized and the period over which this expense is expected to be recognized as of December 31, 2015, for each of the five types of awards issued under the LTIPs. Minimum tax withholdings of $21 million, $16 million, and $13 million for the years ended December 31, 2015, 2014, and 2013, respectively, are reflected as a reduction to Additional Paid-in Capital on the Company's Consolidated Balance Sheet and are reflected as operating activities on the Company's Consolidated Statement of Cash Flows.
(a) All NQSOs and PUs granted under the Company's LTIP were fully vested as of December 31, 2015.
Note 21 — Related Party Transactions
The following table summarizes NRG's material related party transactions with affiliates that are included in the Company's operating revenues, operating costs and other income and expense:
Gladstone — NRG provides services to Gladstone, an equity method investment, under an operations and maintenance agreement. Fees for services under this contract primarily include recovery of NRG's costs of operating the plant as approved in the annual budget, as well as a base monthly fee.
GenConn — NRG has O&M agreements with GenConn Devon and GenConn Middletown that began in June 2011. See further discussion in Note 16, Investments Accounted for by the Equity Method and Variable Interest Entities.