About ATK

ATK Football Club was an Indian professional football club based in Kolkata, West Bengal. The club competed in the Indian Super League, the top flight of Indian football. ATK was established on 7 May 2014 as Atlético de Kolkata, and began play in October 2014.

The team was owned by Kolkata Games and Sports Pvt. Ltd. which consists of former Indian cricket captain Sourav Ganguly, alongside businessmen Harshavardhan Neotia, Sanjiv Goenka and Utsav Parekh. Initially, for first three seasons, Spanish La Liga club Atlético Madrid was also a co-owner; later Goenka bought the shares owned by Atlético Madrid. After the end of their partnership with Spanish giant, Atlético de Kolkata has been rechristened to ATK in July 2017. The team's name and colours are derived from their former Spanish partner.

Under coach Antonio López Habas, Atlético hosted and won the first match of the Indian Super League. They won the inaugural season, beating Kerala Blasters 0–1 in the final. Two years later, under José Francisco Molina, the team won on penalties against the same opponent in the final in same stadium. Currently, ATK holds the most ISL trophies-3 defeating Chennaiyin FC in the 2019-20 season by 3-1.

On 16 January 2020, it was announced that the owners of ATK had bought an 80% stake in Mohun Bagan, a Kolkata club that participates in the I-League. As a result, it was also announced that the ATK brand would merge with Mohun Bagan and a new club would be formed.On 10 July 2020 it was announced that the name of the newly merged team would be known as ATK Mohun Bagan A.C..