Exchange values are the values at which goods, services, labour or assets are in fact exchanged or else could be exchanged for cash

Source/reference: SEEA-EA 2021, para. 8.13.
Note: Exchange values are usually based on observed market prices. Where there is no observable market for a good or service, then exchange values may be estimated based on market prices for similar or analogous items, adjusted if necessary for quality and other differences; or based on what it costs currently to produce the good or service. Assets may be priced at market prices, or the written down replacement cost (current price of an equivalent new asset less accumulated depreciation), or the discounted present value of future returns (SEEA-EA, para. 8.20). As the first two of these options are not generally applicable to ecosystem assets, they are valued using a net present value approach. In other words, first the economic contribution of the ecosystem asset to each ecosystem service that it provides must be estimated (as per the monetary flows tabs for each ecosystem service), then these values for each year into the future should be discounted using an appropriate discount rate, and the discounted values for all years and all ecosystem services added together to arrive at the discounted present value of the ecosystem asset. For further guidance on monetary valuation see NCAVES and MAIA (2022).