The Belgium international left the door open for a Goodison Park exit when recently revealing that he does not intend to sign a new contract, leaving him with two years left to run on his current terms.
Despite the regular speculation surrounding Lukaku's future, Koeman says that no side has declared an interest in the 24-year-old and he sees no reason why he will not still be on Merseyside come the start of next season.
"I expect that Lukaku will stay because until now I did not hear anything from the board that one club is asking about Lukaku," he told reporters.
"You like to keep your best striker, your top scorer, but we also need around that position more productivity. Romelu has two years more on his contract. If there is interest in him then the board will know and they will come to the club if they have interest in the player. That is like everybody."