Magnus Carlsen has been the number 1 ranked player by classical chess FIDE rating since July 2011. This question resolves to the first person who is not Magnus Carlsen to be rated number 1 on a FIDE monthly rating list.

In case of unforseen circumstances (e.g. the creation of a competitor organization to FIDE), I will use a rating list that best includes all top players and all classical games.

If you decide to add additional answers, please add only realistic people; I'll resolve troll answers to N/A.

I will not bet in this market.