>If buyers are willing to pay $80 for a barrel of oil, must BP ask for $80 and not a cent less? Of course not. You may claim they are right to do so, but don’t pretend they have no choice and therefore no blame if there are ill effects to such pricing.
Since we're talking about commodities, prices are most likely set by bids/asks from all participants, rather than your model of a shopkeeper deciding what to write on price tags. If the current bid/ask for crude is at $90/$91, then there's no reason why BP should sell their oil at $80. Doing so would just end up giving $10 worth of value to whomever accepts BP's offer. In fact, you can even make it a business, by beating everyone else to the punch, buying oil at $80, then selling it back to the market at $90. The only way to avoid this is to sell the oil at market prices.
Since we're talking about commodities, prices are most likely set by bids/asks from all participants, rather than your model of a shopkeeper deciding what to write on price tags. If the current bid/ask for crude is at $90/$91, then there's no reason why BP should sell their oil at $80. Doing so would just end up giving $10 worth of value to whomever accepts BP's offer. In fact, you can even make it a business, by beating everyone else to the punch, buying oil at $80, then selling it back to the market at $90. The only way to avoid this is to sell the oil at market prices.