Good–deal bounds are price bounds for a financial portfolio which depends on an individual trader's preferences.
is a set of portfolios with future outcomes which are "acceptable" to the trader, then define the function
is the set of final values for self-financing trading strategies.
Then any price in the range
does not provide a good deal for this trader, and this range is called the "no good-deal price bounds.
then the good-deal price bounds are the no-arbitrage price bounds, and correspond to the subhedging and superhedging prices.
The no-arbitrage bounds are the greatest extremes that good-deal bounds can take.
is a utility function, then the good-deal price bounds correspond to the indifference price bounds.
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