TAP publishes inventory like this in the LIS-LHR market:

C7 D7 Z7 J7 R0 Y9 B9 M9 S9 H9 Q5 P0 V0 W0 A0 K0 L0 U0 E0 T0 O0 G0 N0

In the mid-priced range that's
Q5 P0 V0

If you buy a Q fare ($198 base fare), you accrue 100% to MileagePlus.

If you buy a V fare ($120 base fare), you accrue 100% to MileagePlus.

If you buy a P fare ($154 base fare), you have fallen into a black hole of no mileage accrual, per the published charts at http://www.united.com/cms/en-us/mark...spx?ItemId=319 — based on the fare's nonexistence on the UA charts, it looks like you earn 0%.

Is this really correct? Seems a bit weird to accrue 100% for a cheaper fare and a more expensive fare but accrue 0% for a solidly-in-the-middle fare class. (There are also deep-discount fares that earn 50% priced much lower).

Now, united.com shows the available fare classes in expert mode in a different order than a GDS — which suggests what they're thinking: "Available Cabins: C7, D7, Z7, J7, I3, R9, Y9, B9, M9, H9, Q5, V0, W0, S9, P0, K0, A0, L0, U0, E0, T0, O0, X0, N0". Even so, S earns 50% and K earns 50%, and in the united.com display of fare hierarchy it's "S P K"…