This status is good immediately once you reach the level and through the remainder of the calendar year, then again for the rest of the following calendar year. (upgradedpoints.com)
If you earn 110,000 miles or more in a calendar year, you qualify for a companion pass for the remainder of the calendar year and the entire next calendar year. (personalprofitability.com)
It's valid for the remainder of the calendar year in which you qualify and the year after. (nerdwallet.com)