JASON Koumas has joined Premiership outfit Wigan in a £5.3million deal.
The fee includes a guaranteed payment of £4.6m, with a further £500,000 due on appearances.
Albion would also receive another £200,000 if Wigan either retain their top-flight status next term or get back up while Koumas remains a Latics player.
The 27-year-old ace's JJB Stadium switch makes it two big-money departures in as many days after Diomansy Kamara joined Fulham for £6m yesterday.
Both players had previously expressed a desire to play Premiership football during the new season.
Manager Tony Mowbray said: "I'd like to wish Jason well and thank him for his contribution last season.
"He is a wonderful talent and this is a fantastic opportunity for him.
"But most importantly, this deal will allow me to add new players to the squad who will hopefully become new heroes in what promises to be an exciting time for the club."
Koumas spent four seasons with the Baggies after signing from Tranmere for a then-club record fee of £2.5million in August 2002.
The Wales international carried off the Player-of-the-Season trophy at the end of his first campaign at The Hawthorns, which ended in relegation from the Premiership.
And he further enhanced his reputation during the club's 2003/04 promotion success, scoring ten goals from midfield to earn a place in the Division One PFA XI.
However, Koumas' Albion fortunes dipped the following season.
With the likes of Jonathan Greening and Zoltan Gera signed in the summer, and the January arrival of Kieran Richardson from Manchester United on loan, he was limited to just 13 appearances, including six as a substitute.
Koumas enjoyed a successful season-long loan at Cardiff during 2005/06 and again earned a place in the Championship PFA XI.
And he returned to The Hawthorns last summer to become a virtual ever-present in Mowbray's side, scoring nine goals to help the Baggies reach the Championship play-off final.
He was also voted FourFourTwo Coca-Cola Championship Player of the Year and made the PFA Championship Team of the Year.
In total, Koumas made 141 appearances for Albion, including 21 as a substitute, and scored 23 times.
