contract, the rental is recorded under Intermediate consumption as the purchase of a service produced by the lessor. If the user and the owner are one and the same unit, CFC is considered to represent only part of the cost of using the asset. Certain insurance premiums related to the acquisition or maintenance of fixed assets. Exclusions In UNSNA, excluded are: the value of fixed assets destroyed by acts of war, or exceptional events such as major natural disasters, earthquakes, volcanic eruptions, tsunami, exceptionally severe hurricanes, etc. (e.g. Hurricane Katrina) which occur very infrequently. valuables (precious metals, precious stones, etc.) the depletion or degradation of non-produced assets such as land, mineral or other deposits, or coal, oil, or natural gas. losses due to unexpected technological developments that may significantly shorten the service lives of a group of existing fixed assets. Gross and net capital stocks In UNSNA, the value at current prices of the gross capital stock is obtained, by using price indices for fixed assets at current replacement cost, irrespective of the age of the assets. The net, or written-down value of a fixed capital asset is equal to its current replacement cost, less CFC accrued up to that point in time. Criticism There main criticism made of the way national accounts value CFC is that in trying to arrive at an "economic" concept and magnitude of depreciation, they arrive at figures which are at variance with standard accounting practices. The business income cited in the social account is not the business income reported in profit and loss statements, but an economic income measure which is derived from accounting business income. Thus, the criticism centres both on the valuation principles used, and the additional items included in the aggregate, which are not directly related to depreciation charges in business accounts. Yet the whole computation affects the aggregate profit figures provided. Because of the way CFC is calculated, aggregate profit (or operating surplus the residual item in the product account) is likely to be differ from the accounting profit calculation, which is usually derived from tax data. In Marxian economics, the official concept of CFC is also disputed, because it is argued that CFC really should refer to the value transferred by living labor from fixed assets to new output. Consequently, operating expenditures associated with fixed assets other than depreciation should be regarded as either as circulating constant capital, faux