The Dutchman was asked about his thoughts on the Premier League as he nears the end of his first season in charge.
Slot’s team are top of the league, but he knows their rivals will spend big to close the gap.
He told reporters: “Not particular about the investment (worried) but we know how good we have to be every single day to compete in this league. It is not only the club you are referring to, Chelsea also spend £1.2BN, United spends an incredible amount.
“Every team spends a lot of money over here, that's why it's such an interesting league to be part of. Some seasons this club spends a bit more, other seasons other clubs spend a bit more. That's what makes this league so intense and so difficult to win.
“But that's also the reason why we want to be here: you want to compete against the best, with the best, and we are very happy with the team we have at the moment and we are still able to compete with all the teams that are spending incredible amounts of money.”