Definition of 'Prospect Theory'
A theory that people value gains and losses differently and, as such, will base decisions on perceived gains rather than perceived losses. Thus, if a person were given two equal choices, one expressed in terms of possible gains and the other in possible losses, people would choose the former.
Also known as "loss-aversion theory."
Investopedia explains 'Prospect Theory'
To demonstrate, say one investor was presented with the same mutual fund by two different financial advisors. The first tells the investor that the mutual fund has had an average return of 7% over the past five years. The second advisor tells the investor that the mutual fund has seen above-average returns in the past 10 years but has been declining in recent years. According to prospect theory, even though the investor is presented with the same mutual fund, he or she is more likely to buy the mutual fund from the first advisor, who expressed the rate of return as an overall 7% gain, rather a combination of both high returns and losses.