In shortReaders who land here meaning Endowment Effect rather than Loss aversion are usually searching for phrases like “why is my stuff worth more to me”, “why can't I sell my old car for what it's worth”, “endowment effect explained”.

In shortLoss aversion. 1979 — Prospect theory gives the value function a kink at the reference point — steeper for losses than for gains. Published in Econometrica by Kahneman and Tversky.

1. 1979

   Loss Aversion. Prospect theory gives the value function a kink at the reference point — steeper for losses than for gains. Published in Econometrica by Kahneman and Tversky.

2. 1980

   Endowment Effect. Richard Thaler names the endowment effect in 'Toward a Positive Theory of Consumer Choice' (Journal of Economic Behavior and Organization 1, 39-60): 'Henceforth, I will refer to the underweighting of opportunity costs as the endowment effect.' Mental accounting and transaction utility come five years later, in his 'Mental Accounting and Consumer Choice'.

• Endowment EffectCognitive Biases & the Mind
• Loss AversionCognitive Biases & the Mind