'non-depreciating' is a modern English formation combining the prefix 'non-' (from Latin 'non', meaning 'not') with 'depreciating', the present participle of 'depreciate'.

'depreciate' comes from Late Latin (or medieval Latin) 'depretiare' / 'depretiāre' (from de- + 'pretium' meaning 'price'); the word entered English via Old French/Norman and Middle English as forms such as 'depreciaten' before becoming modern English 'depreciate'. 'non-' is a straightforward negative prefix retained from Latin usage into English.

Initially it meant 'to lessen the price' or 'to lower value'; over time it broadened to mean 'to decrease in monetary value' (for goods/assets) and also 'to belittle' in a figurative sense. 'non-depreciating' therefore denotes something that does not undergo that decrease.