The 26-year-old has scored 10 goals this season but has been played out of position as a centre-forward by head coach Massimiliano Allegri, which has dampened his impact and contributed to a strained relationship with the Milan fanbase.
Milan's financial position is the key driver behind the club's willingness to sell. They are looking to offload multiple high earners to balance the books, and with Leão's contract running until 2028, this summer represents a natural moment to move him on at a price that still represents strong value.
The Premier League trio are understood to be keen to conclude a deal before the World Cup, aware that a strong tournament for Portugal could push his price significantly higher, reports the Daily Mail.
Manchester United have confirmed their desire to sign a top wide player this summer, though the scale of their spending will depend on whether they secure Champions League qualification. Liverpool are searching for a long-term replacement for Mohamed Salah. Manchester City face uncertainty over Pep Guardiola's future and will need to rebuild a squad also losing Bernardo Silva.
Leão has scored 80 goals for Milan since joining from Lille for £30 million in 2019.