(2) Holding Cost: Under this heading are grouped those costs which arise because
of the existence of inventory and which also vary directly with inventory size. In
the latter connection there is again the problem of how to allocate the costs of running
the storage area, for without inventory the storage area could be used for other
purposes or need not exist. The separation of variable from fixed costs and the allocation
of these to various items of inventory according to the product involved (tyres
versus body-shells for example) on the basis of space taken and handling costs could
be achieved, but with much effort. Preferably an attempt should be made to arrive
at an average figure for the whole or a large part of the inventory which will be
representative of the total variable cost involved. Fortunately (or unfortunately as the
case may be!) there is one variable cost which normally dominates others; this is the
cost of financing the inventory. Even if the financing is deemed to be achieved by
debt interest, rates of 15 per cent and above make the existence of stock costly on this
basis alone. If an organisation is short of money, and capital is needed for investment
in a project, the cost of financing inventory may rise to over 20 per cent on the basis
of opportunity cost.