Artículo A5. IAS 33 Paragraph A5

Generally, closing market prices are adequate for calculating the average market price. When prices fluctuate widely, however, an average of the high and low prices usually produces a more representative price. The method used to calculate the average market price is used consistently unless it is no longer representative because of changed conditions. For example, an entity that uses closing market prices to calculate the average market price for several years of relatively stable prices might change to an average of high and low prices if prices start fluctuating greatly and the closing market prices no longer produce a representative average price.