West Brom sponsor Zoopla have decided to end their sponsorship of the club at the end of the season because of Nicolas Anelka's "quenelle" gesture.
Anelka, 34, made the sign, described as an and declared by some to be anti-Semitic, after scoring against West Ham on 28 December, 2013.
Zoopla, co-owned by Jewish businessman Alex Chesterman, will focus on other marketing activities.
The incident is being investigated by the Football Association.
West Brom asked Anelka not to repeat the celebration and have since selected the Frenchman on three occasions.
In a statement, the property company said: "Zoopla has been reviewing its position over the past few weeks in light of the actions of striker Nicolas Anelka during the match against West Ham over the Christmas period."
The agreement, which started in May 2012, was due to finish at the end of the season and Zoopla has decided not to renew.
West Brom say they were "aware the deal could expire" and have been "planning accordingly".
Baggies head coach Pepe Mel said he had no issues when selecting Anelka for Monday's 1-1 draw against West Brom.
"Nicolas is a very good player and a very good professional and I am only the head coach," said Mel.
"If he is suspended by the FA, then he is not able to play, but here at the club we must think about winning football matches and he was available.
"My obligation is just to think about the football and the best interests of West Bromwich Albion."
The FA has brought in an expert to help determine whether the gesture, which Anelka made after scoring was used in an offensive manner.
In the meantime, West Brom have refrained from punishing Anelka.
Lord Ouseley, chairman of anti-racism campaign group Kick It Out, told BBC Radio 5 Live some clubs are guilty of "hiding behind the FA".
He added: "I think the situation has always been from day one that we have clubs who will not take responsibility.
"This has caused a lot of offence to a lot of people. We know that from the complaints we are getting.
"As an employer, you have a responsibility to your fans and have to carry that responsibility out by making sure your players' conduct does not offend. If this happened in any other arena, your employer would be disciplining you."
Anelka said he made the gesture in support of performer Dieudonne M'bala M'bala, whom the French government has tried to ban from making the sign at his shows.
The former Real Madrid player's actions were branded "disgusting" by France's sports minister.
"Of course, I am neither racist nor anti-Semitic and I fully assume my gesture," Anelka tweeted the day after the controversial celebration.
"The meaning of quenelle is anti-system. I do not know what religion has to do with this story.
"With regard to the ministers who give their own interpretations of my quenelle, they are the ones that create confusion and controversy without knowing what it really means. I ask people not to be duped by the media."