U.S. legacy television networks are enduring a steep audience decline midway through the third quarter of 2025, according to newly compiled industry data. Primetime broadcasts excluding sports have lost 20% of their viewers compared with the same period last year, while primetime commercial ratings that include sports have fallen 54%. Cable audiences are also eroding, down 28% on the same basis. Comcast Corp., the owner of NBC, MSNBC and CNBC, is suffering the sharpest contraction among major media companies. Viewership across its cable networks is down 49% year over year, and NBC’s primetime ratings in the key adults-18-to-49 demographic have dropped 80%. Among rival broadcasters, Fox has shed 34% of its primetime audience, ABC is off 12% and CBS 3%.