FlyerTalk Forums - Earning miles on *A codeshare flight operated by another *A partner (Neither UA)

In the Star Alliance system, miles are earned based on the flight operator (not the marketing / codeshare flight number). This is different from some other alliances -- such as Oneworld.

So, for an *A carrier codeshare on operated by another *A partner earnings are based on the flight operator, not the flight marketer.
Additional the fare class is based on the operator's fare class, not the marketing fare class.

UA states

Quote:

The award miles accrued on codeshare flights are based on the operating carrier and their equivalent fare class. This could result in differences between the purchased booking class and the booking class flown, which determines the number of base and Premier qualifying miles and Premier qualifying segments earned.

related thread - Earning miles on non-*A operated *A codeshared flights [Consolidated]