ESPN reported on Monday that United had turned down bids for Maguire and Scott McTominay of around £20m, but West Ham returned with an offer closer to a combined £60m.
Sources told ESPN the clubs have now come to an agreement. Sources added he has been given permission to talk to West Ham but is not completely sold on the move and would need to be convinced by David Moyes.
West Ham are yet to meet United’s £40m valuation of McTominay.
Maguire joined Old Trafford from Leicester City in 2019 as part of an £80m deal that made him the most expensive defender in history. However, after just eight starts in the Premier League last season, United have been willing to listen to offers for the defender.
Maguire, 31, who has 57 caps for England, is in need of playing time to stay in international boss Gareth Southgate’s plans, with Euro 2024 set to take place next summer.
Information from ESPN’s Rob Dawson contributed to this story.