Although there’s no official confirmation from either airline, it’s being widely reported that Virgin America has agreed to be acquired by Alaska Airlines. Sources say an announcement could come as soon as Monday.

According to a Wall Street Journal report (subscription required), Alaska will pay around $2 billion for Virgin America, a hefty premium over the company’s current market value of just $1.5 billion.

Unconfirmed rumors earlier this week had Virgin America weighing competing bids from Alaska and JetBlue, as well as considering expressions of interest from Delta and Etihad.

In the event of an Alaska-Virgin America merger, the combination would make Alaska the country’s fifth-largest airline, based on passenger traffic.

In many critical respects, the more logical merger partner for Virgin America is JetBlue. Both operate Airbus fleets, and have revenue-based loyalty programs. Their route networks are complementary, with Virgin America’s strength in the west and JetBlue’s in the east. While not identical, Virgin America’s corporate culture is much more like JetBlue’s than it is like Alaska’s.

But in the end, mergers and acquisitions are financial transactions, and a more lucrative offer trumps a weaker one.

Reader Reality Check

Which is the better merger partner for Virgin America, JetBlue or Alaska Air?

After 20 years working in the travel industry, and 15 years writing about it, Tim Winship knows a thing or two about travel. Follow him on Twitter @twinship.