West Ham United have confirmed that Arthur Masuaku has completed a permanent transfer to Turkish Süper Lig side Beşiktaş J.K.
Masuaku initially joined Beşiktaş on a season-long loan from the Hammers in August and has featured 27 times in all competitions for the Turkish team, scoring twice.
The DR Congo international moved to West Ham from Greek side Olympiacos in 2016 and made 128 appearances in all competitions for the Irons, including 105 in the Premier League.
West Ham included a €2.2m (£1.94m) obligation to buy in their season-long loan contract.
In 2019 Masuaku signed a contract extension to keep him at West Ham until June 2024 on a basic wage of £40,000 per week.
With wages saved the Hammers will have banked £4m in a transfer fee and savings in his weekly wages.
West Ham continued to heavily subsidy his wages while in Turkey.
West Ham completed the signing of Masuaku from Olympiakos for £6.39m in 2016 while the player was just 22 years of age.