The T&C say "by 12/31" or something to that effect. IIRC, last year they began posting shortly after 12/15 in a series of sweeps, presumably so that UA and customers would have time to address any discrepancies, and pax could make up a segment or few miles if necessary before the end of the year.

Enough people swamped UA with calls saying, "Where are MY double miles?" as the sweeps went on that UA may rethink that this year, but they have much more to gain by posting "early," IMHO.