West Ham boss David Moyes insists he would not sell Declan Rice even for £100million.
Hammers co-owner David Sullivan is understood to value his prized asset at somewhere around an eye-watering nine-figure sum.
Chelsea and Manchester United are regularly linked with Rice but even those powerhouse clubs face being priced out of the running.
Moyes said: "I don't agree with the owners that Declan Rice is a £100m footballer. Far, far more than £100m. Far, far more.
"I look at the players who have joined some clubs from overseas and come in and nowhere near had the impact Declan Rice would have.
"I certainly wouldn't put a price on it. You can decide which figure you want to put on it but I wouldn't be sanctioning anything like that, that's for sure."
Rice last week admitted he had his sights set on a Premier League top-four finish with West Ham this season.
The Hammers can boost their unlikely bid for a Champions League spot with victory over Leeds on Monday night.
But Moyes says they do not need to qualify in order to keep hold of the England midfielder.
He added: "Do we need the Champions League to keep Declan? No, because Declan is under contract first and foremost, so he can't go anywhere no matter what, and I keep saying it and I hope people know that when I say something, I mean it.
"We've not had an offer for Declan Rice and I hope we don't get one. And you've got an idea now of where we'd need to be if it was even going to be considered, certainly be me.
"If we could finish in Europe, in some sort of European position, I think it would be progress. And that would be progress for Declan Rice as well because he's been at West Ham while they've been bobbing around the bottom, so this is new for Declan as well.
"Declan seems very settled and in fact he is captaining West Ham, he plays for England, and I want to keep Declan thinking that his ambitions can be achieved here at West Ham and I will have to keep pushing that and keep pushing that with the owners as well.
"For me, I have watched the prices of some players who have gone to clubs recently and they could not lace Declan Rice's boots."
This time last year West Ham played their last match before lockdown, a 1-0 defeat to Arsenal which left them above the drop zone only on goal difference.
"I actually hoped in many ways the season might have been cut," admitted Moyes.
"So it shows you where we've come to now – there's no questions about relegation, all the questions are about 'can you be in the top four, can you get into Europe'? The transformation from then to now is great."