Manchester will be the source of a third of all Premier League transfer expenditure so far this summer, following the record-breaking deals struck for Kevin de Bruyne and Anthony Martial by City and United respectively.
Over £247m will have been spent by the two Manchester giants during the current transfer window, representing 33 per cent of the Premier League's total £760m outlay.
Manchester City splashed out £55m on Wolfsburg's Kevin De Bruyne on Sunday - breaking their own transfer record in the process - while local rivals United are poised to make young French forward Anthony Martial the most expensive teenager in football history with a £36m deal today.
Manchester has been the Premier League's northern powerhouse so far this summer, with City and United having spent £73m more than all six London clubs combined as the two highest spenders in the league so far.
City boss Manuel Pellegrini has been handed £140m to spend on high-profile signings Raheem Sterling (£44m), Nicolas Otamendi (£31m) and Fabian Delph (£8m) as well as De Bruyne, while United manager Louis van Gaal has been allowed to break the £100m barrier for the second consecutive season as Martial is set to join summer acquisitions Morgan Schneiderlin (£24.5m), Memphis Depay (£19m) and Matteo Darmian (£12.6m) and Bastian Schweinsteiger (£12.6m).
Martial will break new teammate Luke Shaw's record as the most expensive teenager in history, and the French 19-year-old will become United's third most expensive signing behind Angel Di Maria (£59.7m) and Juan Mata (£37.1m).
Van Gaal insisted on Sunday that United wouldn't panic buy after losing 2-1 at Swansea. He said: "We shall not buy another player that we have not scouted before."
Although both Manchester clubs have spent heavily to improve upon trophy-less campaigns last season, their sprees have been supplemented by significant earnings from outgoing players.
City have raised over £47m from departing players including the £19.6m sale of Alvaro Negredo to Valencia, while United have generated £62m - a figure which could soon grow higher if David De Gea and Javier Hernandez's departures are confirmed.