6. INCOME TAXES

The effective income tax rates for the first quarters of 2018 and 2017 were as follows:

Quarter Ended
March 31,
2018			2017
	31	%		9	%

The effective income tax rate for the first quarter of 2018 reflects the impact of the U.S. Tax Cut and Jobs Act (the “Tax Reform Act”) that was passed into legislation in December 2017. The Tax Reform Act reduces the U.S. maximum rate of income taxation from 35% to 21% applicable to taxable years beginning after December 31, 2017. As a result, for the full-year 2018 we are currently estimating an effective income tax rate of approximately 30%.

The lower first quarter 2017 effective income tax rate reflects and approximately $5 million net benefit resulting from Comcast Corporation’s (“Comcast”) exercise of 1.4 million vested stock warrants in January 2017, as the stock warrants appreciated in value since their vesting, resulting in an income tax benefit to us when exercised.