Australian champion Winx and American star Arrogate sit on top of the world with ratings of 127 in the first rankings for the year.
Arrogate, who runs in the World Cup in Dubai at the end of the month, has had one start in 2017 for victory in The Pegasus.
Winx has won the Gr. 2 Apollo Stakes and Gr. 1 Chipping Norton Stakes this year with her next start scheduled for March 18 in the George Ryder Stakes.
Hartnell, who finished second to Winx in the Apollo has a rating of 123 making him the world's third highest.
At the end of last year, Arrogate was the world's best on 134 with Winx rated the world's best horse on turf on 132 with California Chrome splitting the pair.
