Alaska Airlines is not part of any global airline alliance, but has ties with many airlines for earning and redeeming miles.
Alaska Airlines has just started a new Mystery Sale for buying or Mileage Plan miles and getting up to 50% bonus in the process (or maybe even more), although my personal offer was just up to 35% bonus. The expiry of this sale is unclear.
You can access Alaska’s web page for buying and gifting miles to check your bonus here.
Note that Alaska Airlines doesn’t limit the number of miles that you can purchase over calendar year. They merely have 60,000 miles limit before bonus per transaction (used to be 40K).
Points.com (company that handles many of these miles/points sales) has quite a few campaigns now with “mystery” or “surprise” bonus amounts. I guess that they want to get email recipients to click through their site to check the bonus amount.
This could be a good way to bump up the balance and then redeem for premium class trip on Emirates or Cathay Pacific. Alaska doesn’t limit the number of miles that you can buy over a calendar year or promotional period like many of the other airlines do (some use these miles exclusively for Emirates awards).