According to FIDE regulations, the list of players includes the top two performers from the 2014-2015 Grand Prix: Hikaru Nakamura and Fabiano Caruana (both of the USA); the winner and runner-up of the 2015 World Cup, Sergey Karjakin and Peter Svidler (both of Russia); as well as the loser of the 2014 World Chess Championship match, Viswanathan Anand of India; Veselin Topalov of Bulgaria and Anish Giri of the Netherlands, based on their 2015 FIDE ratings are likely to have qualified to participate. The eighth and final participant is Levon Aronian of Armenia, who was chosen as Wild Card entry by the Organizers.
Another paragraph informs that Agon is still very much part of the story.
About World Chess by Agon Limited: Agon Limited is the official partner of World Chess Federation (FIDE) and owner of commercial rights to the World Chess Championship cycle. The company aims to develop and commercialize chess, create favorable environment for partners, players, and brands, and to significantly expand the broadcast coverage of the sport. With this in mind the company introduces World Chess brand, targeting 600+ million chess players and spectators all over the world.
Agon became owner of commercial rights in 2012. The company successfully managed the 2012-2013 Grand Prix cycle, the 2014 World Championship Match, and the 2015 Rapid and Blitz World Championships. For commercial and partnership opportunities, please visit www.agonlimited.com.
The last time I recall covering Agon was on my main blog during last year's World Championship match, Carlsen - Anand II : Rumblings (November 2014). The post started,
Pre-match Press Conference: Who was that fellow sitting to the right of the match stakeholders? Introduced as 'the organizer of the tournament, Ilya Merenzon', this was the first time I had become aware of him.
Agon also received a subsequent mention on this WCC blog in 2014 FIDE General Assembly : Whither the World Championship? (December 2014).
Then let's hear from the Presidential Board in November about forthcoming events. 4.5. Agon. Annex 13 is a letter from Agon with a change in the Agon/FIDE interface team. [...] I don't have much to add here. It's Christmas Eve and there are better things to do!
Christmas is long past, so let's look at that letter, which is dated 17 September 2014.
'The Chairman' was identified as Mr. L. Buckley assisted by Mrs. C. Farrow as secretary. Mentioned in the clipping are Andrew Paulson, Ilya Merenzon, and Matvey Shekhovtsov. Now that we know the Agon cast of characters, we can continue with the story.