400 million? maybe he has lost his mind by setting the price that high or it's just his tactic so that no club will make an offer because he sees this striker as a valuable asset that must be well looked after by the club, but I'm pretty sure no club is willing to buy at that high a price even only for the price of 150 million as you mentioned because his value is not more than 100 million, especially since this season there has been a decline in his performance which of course his appearance will be the benchmark for any club that wants to buy him.
They lost the opportunity to sell him at a high price last season because at that time several clubs were reportedly interested in him, or indeed it was all just rumors.