The peak trade-in price for the iPhone 6 and/or iPhone 6 Plus was £485.05 ($730), with the Galaxy S5 and the Galaxy Note 3 trading in for £320 ($482) and £286 ($431) respectively.
The study found that Apple is the most traded-in handset brand, with 38% market share and an 81% customer loyalty — only 9.58% of customers trading-in an iPhone moved to a Samsung handset, and 2.8% purchased an HTC device.
Samsung and HTC scored 34.37% and 7.21%, respectively, when it comes to trade-in market share.
The two Apple rivals scored even lower when it comes to brand loyalty. 44.26% of people trading-in an old Samsung device bought a new one, with 34.77% of them going over to Apple. Finally, only 26.71% of HTC device owners who traded their devices in stuck with HTC, with 35.5% of them buying an iPhone, and 16.34% of them moving to Samsung.
While Apple, Samsung and HTC devices retain their value over time, some better than others, handsets from BlackBerry, Nokia and Google are deprecating the fastest, according to the study.