With just under half of this season's games played in the English Premier League, teams now have the month to reinforce ahead of the second half the campaign.
The winter transfer window opens on January 2 and closes on February 1. Last year Premier League clubs spent just over $310 million on new talent in that window.
Though the financial impact of the coronavirus pandemic means that figure is unlikely to be beaten, there is still plenty of business to be done with teams look bolster their ranks to avoid relegation or mount a late title charge - assuming the season actually finishes amid spiking infection rates in the UK.
Here is Insider's team-by-team guide as to who every club needs to sign this month.