The Sun says United vice-chairman Ed Woodward is ready to match Leicester's £80million valuation for Maguire.
Woodward will stop at nothing to land the England centre-back — who has been told he can expect a five-year deal worth £350,000-a-week.
Leicester are holding out for a world-record fee for a defender — and add-ons could take United to the price they want for the 26-year-old.
United also have an ace in the pack in their bid to snap up Maguire.
Ole Gunnar Solskjaer's No 2, Mike Phelan, gave Maguire his first Premier League break when he was boss of Hull.