How are high performers getting shortlisted?

I got A band and got 11.9% hike but some associates in my project got 7% hike for the same A band. We observed that 1) It doesn’t depend on Rating 2) it doesn’t depend on consecutive A bands 3) There’s no A+ band as such 4) It doesn’t depend on high talent flag(wings1,wings2,..) 5) It doesn’t depend on experience 6) it doesn’t depend on promotion

Then on what basis are these people shortlisting high performers? Does anyone have any clarity?