The shipping expense thereby saved was enough to allow a price reduction to a dime per can from 30 cents.

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Common causes of slipping margins include increased product costs, increased shipping expense, finance costs, sales and discounting or inventory shrinkage due to theft or waste (food business).

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Packaging and shipping orders is a central expense for Amazon, which has been building warehouses to speed delivery times.

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The studios -- and Technicolor and Deluxe, the two primary companies that "print" films -- certainly appreciate this cost savings, since printing and shipping thousands of copies of a major release wasn't a trivial expense.

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Contrary to the obvious assumption, rising fuel prices might actually cause the use of ships for freight, as manufacturers reduce fuel use not by shipping things shorter distances, but by relying more heavily on efficient sea freight at the expense of less efficient land- and air-based modes of transport.

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The Guggenheim Shipping ETF ( SEA) holds 31 different shipping companies, with the highest weighting just 4.9% of the total fund and an expense ratio well below 1%.

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