Sports equipment giants Adidas, Nike and Puma are pushing rivals out of the market at the European Championship finals, more than doubling their share of the teams they supply over the past 20 years, according to a study released Thursday."The biggest brands in the sector are getting bigger," the Repucom sports marketing company said. At the 1996 tournament in England, half of the 16 teams were kitted out by brands outside the leading trio. In France this year, that has been cut to four of the 24 teams, said the study.German group Adidas has seen its share of football profits cut in recent decades as Nike grows. But it still provided kits to the last five Euro winners and accounts for nine (37 percent) of the teams at this year's tournament, up from five (31 percent) in 1996. Nike has seen its share grow from one team (6 percent) in 1996 to six (25 percent) at Euro 2016. But Puma has also been spending more heavily on sponsorship as it bids to keep up with the leading duo. Its share has gone up from two teams (13 percent) to five (21 percent). Repucom said Adidas and Nike are locked in a "fiercely contested commercial battle" at Euro 2016. Jon Stainer, managing director of Repucom U.K., said: "In football, on this scale, there are only two occasions when we really get to see the Nike and Adidas fight it out, the FIFA World Cup and the UEFA European Championships."Both tournaments provide vital platforms for both brands where the activation of rights and content is a fiercely fought one."Sponsoring teams give the equipment giants "a host of opportunities to increase exposure and engage fans. In grabbing the attention of potential customers and driving revenues, the next month will be an important time for the brands where we are likely to see social media and video content come to the fore."He said the "dominance in kit supply is as much to do with the number of competing kit manufacturers reducing [over 20 years] as it is based on the two brands' current supremacy.""Whilst we are seeing the likes of Warrior and Under Amour come into the fold, it is clear that the sport is still dominated by two brands," Stainer said. Nike has a lead in its deals with individual players. The U.S. giant has a long term accord with Portugal's Cristiano Ronaldo, who Repucom said in commercial terms "dwarfs all other Euro 2016 players." The company estimated his personal deals to be worth 19 million euros ($21.5 million) a year. Wales' Gareth Bale, linked to Adidas, was second on an estimated four million euros ($4.6 million).