There are many threads on this topic. The MQM Boosts will post (or can be selected with Reserve) only after statement close. When the Boost is posted it will be backdated with an activity date in 2018 and count towards 2018 totals. Finally, at a later date, DL runs regular sweeps which will update your status (if there is a change), and your MQM Rollover amount for 2019. This happens automatically every single year. I passed the spend threshold for my second MQM boost after my statement close on 12/25, so now I will have to wait until next statement close on 1/25 for my MQM Boost. These MQM will post with an activity date of 12/31/18 and then when DL runs the next sweep they will be added to my MQM Rollover for 2019. I have done this multiple times in the past and it all works out in the end.