​The biggest sport on U.S. TV and streaming — NFL football — commands the largest percentage of “casual” viewers of any of the four most-watched sports TV franchises — at 44%, according to S&P Global Market Intelligence.S&P says “casual” sports fans are defined as those who watch less than five hours of sports per week, while “avid” fans watch 10 hours or more and “moderate” fans watch five to 10 hours.AdvertisementAdvertisementAdvertisementWhile avid fans serve as the foundation for most sports — at 15% to 20% — casual sports fans comprise around 42% of U.S. adults and are the largest group, according to analysts.Other sports — including Major League Baseball, NHL hockey and NBA basketball — were in the 32% to 39% range.The highest percentage of “casual” sports (29%) is with viewers 65 years and older, followed by those who are age 55 to 64, at 22%.The smallest group is 18- to-24-year-olds, at 8%.When respondents were asked which sports they watched or planned to watch, football — whether the NFL or the NCAA — led with a dominating 53% number.AdvertisementAdvertisementAdvertisementOn the flip side, the most “avid” fans were for the NBA (29%), followed by the NHL (28%), the MLB (27%) and the NFL (22%).The next-highest were baseball and basketball fans, tied at 36%. Ice hockey was next at 20%.The every-other-year two-week events — the Winter and Summer Olympics — were at 41% and 38%, respectively.S&P’s results were from a study of 1,045 adults, conducted in the first quarter of 2026.