Originally Posted by Bowgie

MSPeconomist is definitely correct insofar as the threshold bonus on each 25k (or 30k for the Reserve card). The 5k sign-up bonus *probably* follows the same December 31 "spend" deadline (and not when the miles actually post).

As a side note, it always comes up that someone spends on December 31, and the merchant posts the sale to Amex on Jan 1. In that case, the MQM's will towards a threshold bonus in 2020, not 2019.

As past years go, our Skymiles MQM balances in January will be nonsensical until Delta's computers catch up. Negative balances when Delta deletes the MQM's for 2020 status. MQM's post to a flyer's account at the close of his or her billing cycle. Quite possible for someone to not get their earned status on Delta.com until end of January or even early February.

But the general point is correct that the status update *should* backdate to January 1.
No idea if Delta will handle the timing of the 5k MQM bonus per the OP's question automatically, or whether OP will need to ask Delta to make a correction in February -- assuming the MQM's wrongly credit for 2020.

Same for missed RDM bonuses for January flights taken before the new status is recognized. In any case, I'd give Delta until February to sort this out.