The Frenchman was voted the club's player of the month for September after delivering a host of excellent performances in the centre of the park for the Baggies.
Former boss Tony Mowbray brought in the tough tackling 22-year-old from Paris Saint-Germain in January 2009 on loan before the club paid just £175,000 for his services.
He has proved a revelation for the price they paid, with Villa, the Toffees and Rovers all thought to be targeting the player for a possible swoop in January.
However Mulumbu insists he is happy at The Hawthorns and is just happy to be playing in the Premier League.
"I am happy to be doing well at the moment, we are playing very well," he said.
"We proved that against Arsenal (where they won 3-2 in September), the Premier League is a fantastic league so I am enjoying myself here, and I am very happy with the Baggies."