West Ham would need to receive "ridiculous money" to consider allowing Dimitri Payet to leave the club this summer, according to the player's agent.
Payet enjoyed a superb first season with West Ham, following his move from Marseille last summer, and scored the winning goal in France's European Championship opener against Romania on Friday.
Chelsea, Paris Saint-Germain and Manchester City have all been linked with a summer bid for Payet, 29, but his agent -- Mark McKay -- believes it will take an extraordinary offer to convince the Hammers to sell their star midfielder.
"As far as I am concerned, he's been happy at West Ham and it's down to West Ham that he's in the position that he is in," McKay told Sky Sports. "When he first came last year we hoped for the best with him. We knew that he was a really good player, but I don't think anyone could really expect what he has gone on to do in the Premier League so far.
"He's doing great now for France and to get him now, you've got to be talking ridiculous money. But football is football, so you never know."
However, Diafra Sakho -- another of McKay's clients -- is considering leaving West Ham unless he receives assurances over his future in the first team.
Sunderland are reportedly interested in the striker and McKay has admitted that Sakho may be forced out of the club.
"I think if you look at Diafra, he is a victim of the success West Ham have had," the agent said. "Now they are going to the Olympic Stadium, they want to kick on and he may just be left behind, he's not that star name they are looking for maybe.
"So, we'll wait and see on that. It's up in the air at the moment. He's a West Ham player as it stands until David Sullivan and Slaven Bilic turn round and say differently."