Mostly comes from company responses to the question -has Polar ever made any money? The response was no. Also comes from a summer time meeting where the reported year loss for Polar was 40 million (admittedly before the re-audit and updated numbers in Sept) and the loss for Atlas was 8 million. They said the Atlas loss was mostly due to the fact that ,while Atlas couldn't "officially" transfer money to Polar, they could pay all of their mechanic contractors and other ground contractors. Thus Atlas has been supporting Polar. Information also comes from my own observations of hearing Polar flights takeoff that were empty or nearly so.
The reason Atlas is having to park airplanes instead of Polar is simple. Polar has a route structure that they have to maintain even if they are losing money. This is called "developing a market." The trade off (and there are always trade offs in economics) comes at Atlas expense. The opportunity costs to Atlas management apparantly currently favor Polar. It is not however because they have made so much money, or even that they might make money. They are simply one segment of a business model. It is currently easier for management to park Atlas airplanes than to go out and get new ACMI contracts in that shrinking market.
The thing that really upsets Atlas pilots is that they had a 600 million surplus of cash prior to buying Polar. Now Atlas is way in the hole. Polar was bought using Atlas pilots profit sharing. The Tokyo rights that they are so proud of don't mean a hill of beans if you aren't hauling any cargo there. They truly don't mean all that much anyway.