The Tigers sold the England international to Leicester City two summers ago for £15m. The deal included a sell-on clause that will see the East Riding club receive 15 per cent of any profit made by the Foxes.
With Leicester having agreed a deal that could reach £80m through add-ons - potentially eclipsing the £75m that Liverpool paid for Virgil van Dijk - City’s coffers are in for a huge boost.
Maguire’s move is understood to involve United paying a guaranteed £60m for the 26-year-old. This will bring City a £6.75m payment that could rise by a further £2.25m, depending on how Maguire fares at Old Trafford.
Sheffield United, who sold Maguire to Hull for £2.5m, will also receive a small payment under the terms of that 2014 transfer.
The England international is expected to undergo a medical in Manchester tomorrow.