S.L. Benfica 2015, Benfica reported to have 246,401 members; however, after a scheduled renumbering by the club in August 2015, the number decreased to 156,916. In April 2017, Benfica reported they had a total of 184,264 members by 31 December 2016. Benfica has rivalries with Sporting CP and FC Porto, with whom it forms the "Big Three": Portugal's most decorated clubs. None of them have been relegated from the Portuguese league since its establishment in 1934. As Lisbon-based clubs, Benfica and Sporting have shared a rivalry for over a century; it all started in 1907 when eight prominent Benfica players defected to
1973–74 S.L. Benfica season on 11 February. Taking advantage of Porto's draw and Sporting's loss, Benfica won their match and cut Sporting's lead to just one point. In early March, Benfica surpassed Porto after their rival dropped points in Guimarães. On 10 March, Benfica visited Estádio das Antas to play Porto, losing 2–1. With this defeat, Benfica was now with 35 points, three less than Sporting. Following a home win against Guimarães, on next match on the road, Benfica drew with Beira-Mar by 1–1. The draw allowed Sporting to open a four-point gap with five matches to go, practically ending any hope of Benfica