"An economic concept established by economist Richard Thaler, which contends that individuals divide their current and future assets into separate, non-transferable portions. The theory purports individuals assign different levels of utility to each asset group, which affects their consumption decisions and other behaviors." Investopedia.com: Mental Accounting
"If Richard Thaler's concept of mental accounting is one of two pillars upon which the whole of behavioral economics rests, then prospect theory is the other."
Belsky and Gilovich (1999)
"...mental accounting as a cause of a historical equity premium that has been too high, relative to the underlying fundamentals..."
Shefrin (2000)
"Mental accounting: Thaler (1980) and Kahneman, Knetch and Thaler (1991)."
Taleb (2004)