World No. 2 Jannik Sinner has criticized the four tennis Grand Slams for inaction over prize money and welfare discussions amid the ongoing antitrust lawsuit separately lodged by the Professional Tennis Players’ Association.“We had good conversations with the grand slams at Roland Garros and Wimbledon, so it was disappointing when they said they cannot act on our proposals until other issues are resolved,” Sinner said in an interview with the Guardian. “Other issues” refers to the lawsuit from the PTPA, which added the Australian, French and U.S. Opens and Wimbledon as defendants on its New York City filing in September. The Grand Slams’ deadline to respond was recently extended to December 22 2025.Sinner’s comments follow a group of leading men’s and women’s tennis players’ sending a second series of letters to the Grand Slams, pushing for reform of the sport.The second letter was sent to all four majors July 30, and signed by almost all of the world’s leading players, including Aryna Sabalenka, Coco Gauff, Iga Świątek, Carlos Alcaraz and Jannik Sinner. Novak Djokovic is the only signatory on the original letter, sent March 21, who is not a part of this one.The original letter included the top-10 players on each tour from the week of March 3, apart from former Wimbledon champion Elena Rybakina (who was replaced by then world No. 11 Mirra Andreeva). The most recent letter also includes Jack Draper, Lorenzo Musetti, Ben Shelton, Frances Tiafoe and Amanda Anisimova, reflecting their improved rankings by the end of July. Of the men’s and women’s top 10s, only Djokovic, Rybakina and Karen Khachanov, whose rise up the rankings came more recently, were missing from the newest letter. The aim of the group is to represent the interests of players at all levels.The most recent letter, which has been reviewed by The Athletic, reiterated the players’ desire for three key areas of reform from the Slams: