@techreport{HaanSunSundeetal., type = {Working Paper}, author = {Haan, Peter and Sun, Chen and Sunde, Uwe and Weizs{\"a}cker, Georg}, title = {Non-Additivity of Subjective Expectations over Different Time Intervals}, series = {Berlin School of Economics Discussion Papers}, journal = {Berlin School of Economics Discussion Papers}, edition = {No. 4}, doi = {10.48462/opus4-4660}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:b1570-opus4-46602}, pages = {38}, abstract = {We examine the additivity of stock-market expectations over different time intervals. When asked about a ten-year interval, survey respondents expect a stock-price change that is not equal to, but closer to zero than, the sum of their expectations over two shorter time intervals that cover the same ten years. Such sub-additivity is irrational in that it cannot stem from aggregating short-term expectations. Model estimates show that the pattern is consistent with a time perception where shorter time intervals have a proportionally larger weight. We also find that the respondents' degree of additivity is correlated with making larger financial investments.}, language = {en} }