FC Barcelona has signed one of the largest shirt sponsorship deal ever seen which could make the club even wealthier than Real Madrid, currently the richest football club in the world.

The four year deal with Japanese online firm Rakuten is worth £47m ($58m) a year and will begin with the 2017-18 season. It stands to earn the club at least £188m with additional incentives should the club win Spain’s La Liga or the European Championship League.

The deal between FC Barcelona and Rakuten may be extended for a fifth year.

Rakuten employs over 13,000 staff in Japan and had a turnover of almost £15bn in the first three financial quarters of this year. It is Japan’s biggest e-commerce firm and already owns J-League club Vissel Kobe and baseball club Tohoku Rakuten Golden Eagles.

The sponsorship deal is thought to be an effort to raise Rakuten’s profile globally.

Barcelona stands to become even wealthier from 2018 when the club begins a new 10-year kit sponsorship deal with the US sportswear firm Nike. The deal is expected to see Nike pay £134m a year.

The extra money which Barcelona will earn from these sponsorship deals will help it to pay for the planned expansion of its Nou Camp stadium to 105,000 seats.

The largest football clubs in the word are currently Real Madrid, Barcelona, and Manchester United.