AMERICAN TOWER CORPORATION AND SUBSIDIARIES
NOTES TO CONSOLIDATED AND CONDENSED CONSOLIDATED FINANCIAL STATEMENTS
During the nine months ended September 30, 2017, the Ghana Revenue Authority issued a clarification to its income tax law, which resulted in a benefit to income tax expense of $11.6 million.
8. STOCK-BASED COMPENSATION
Summary of Stock-Based Compensation Plans—The Company maintains equity incentive plans that provide for the grant of stock-based awards to its directors, officers and employees. The 2007 Equity Incentive Plan, as amended (the “2007 Plan”), provides for the grant of non-qualified and incentive stock options, as well as restricted stock units, restricted stock and other stock-based awards. Exercise prices for non-qualified and incentive stock options are not less than the fair value of the underlying common stock on the date of grant. Equity awards typically vest ratably, generally over four years for time-based restricted stock units (“RSUs”) and stock options and three years for performance-based restricted stock units (“PSUs”). Stock options generally expire ten years from the date of grant. As of September 30, 2017, the Company had the ability to grant stock-based awards with respect to an aggregate of 8.5 million shares of common stock under the 2007 Plan. In addition, the Company maintains an employee stock purchase plan (“ESPP”) pursuant to which eligible employees may purchase shares of the Company’s common stock on the last day of each bi-annual offering period at a 15% discount from the lower of the closing market value on the first or last day of such offering period. The offering periods run from June 1 through November 30 and from December 1 through May 31 of each year.
During the three and nine months ended September 30, 2017 and 2016, the Company recorded and capitalized the following stock-based compensation expense (in thousands):
Three Months Ended September 30,
Nine Months Ended September 30,
Stock-based compensation expense
Stock-based compensation expense capitalized as property and equipment
Stock Options—As of September 30, 2017, total unrecognized compensation expense related to unvested stock options was $15.2 million, which is expected to be recognized over a weighted average period of approximately two years.
The Company’s option activity for the nine months ended September 30, 2017 was as follows:
Number of Options
Outstanding as of January 1, 2017
Outstanding as of September 30, 2017
Restricted Stock Units—As of September 30, 2017, total unrecognized compensation expense related to unvested RSUs granted under the 2007 Plan was $115.8 million and is expected to be recognized over a weighted average period of approximately two years.
Performance-Based Restricted Stock Units—During the nine months ended September 30, 2017 and 2016, the Company’s Compensation Committee granted an aggregate of 154,520 PSUs (the “2017 PSUs”) and 169,340 PSUs (the “2016 PSUs”), respectively, to its executive officers and established the performance metrics for these awards. Threshold, target and maximum parameters were established for the metrics for a three-year performance period with respect to the 2017 PSUs and the 2016 PSUs, and for each year in the three-year performance period with respect to PSUs granted to executive officers in 2015 (the “2015 PSUs”), and will be used to calculate the number of shares that will be issuable when each award vests, which may range from zero to 200% of the target amounts. At the end of each