The CIES Football Observatory suggest United paid €27.9 million (£20.4 million) over the odds for Martial, while De Bruyne’s estimated value was €26.6 million (£19.4 million) lower than the €74 million (£54 million) fee City paid Wolfsburg for the Belgian.
However, while City overspent on De Bruyne, they also reportedly signed the most undervalued player of the window, with Raheem Sterling moving to the Etihad for €32.1 million (£13.4 million) less than his estimated €95.1 million (£69.5 million) valuation, per CIES.
Here are the top-five most overpriced and the top-five most undervalued players of the summer transfer window in 2015:
It is largely unsurprising that the 19-year-old Martial tops the list as there was widespread incredulity when United splashed out such a huge amount of cash for the youngster on deadline day.
Though he is clearly very talented, his achievements to date do not warrant a £36 million transfer fee, and United are undoubtedly taking a big gamble on his potential, per the Mirror‘s Darren Lewis on Sky Sports’ Sunday Supplement:
I don’t think it is a risk as such but they have massively overpaid, whatever they say, for a player who has so far scored 13 goals for Monaco. He did not score any for Lyon before. They rave about him, they call him the new Thierry Henry. They can’t speak highly enough of him in France. It’s just an incredible amount of money to pay for a player who has done so little in his career.
De Bruyne has done more to warrant his £55 million fee, netting 10 goals and providing 20 assists in a stellar Bundesliga season with Wolfsburg in 2014-15, per WhoScored.com.
Another City purchase also takes sixth place in the overpriced list with the value of Nicolas Otamendi’s switch from Valencia deemed to be €13.7 million (£10 million) more than expected.
Sterling’s position as the most undervalued player of the window comes as something of a surprise as there was widespread speculation at the time of his switch from Liverpool as to whether he was worth £49 million, per BBC Sport:
Similarly Martial could yet prove his worth if he hits the ground running at United, but the Red Devils do indeed seem to have taken a big risk in splashing out on an unproven teenager.
The new Man City number 7. But is Sterling worth it?
— BBC Sport (@BBCSport) July 14, 2015
He has started well with the Sky Blues and could prove a long-term asset for the Manchester outfit considering he is likely only to improve as he gains more and more experience.