Charlotte became the first British rider to take the top spot in September after winning individual and team gold at the London Olympic Games.
But Adelinde Cornelissen and Jerich Parzival reclaimed the placing they had held since July 2011 in November.
Charlotte and “Blueberry” are now back on top following wins in both Reem Acra FEI World Cup dressage classes at Olympia.
They currently have 2943 points to Adelinde and Parzival’s 2907 putting them top in the FEI world dressage rankings.
Germany’s Helen Langehanenberg and Damon Hill NRW remain in third place with 2,731, followed by Laura Bechtolsheimer and Mistral Hojris, who are still in fourth place on 2,555 points.