Racionalni špekulativni baloni - kritički pogled

Abstract

Prema teorija racionalnih balona, balon je prisutan kad god cena efekta progresivno divergira od nivoa koji je određen ekonomskim fundamentima, jer tržišni učesnici očekuju da će cena efekta nastaviti da raste eksponencijalno u budućnosti (samo-ispunjavajuća očekivanja), što obećava značajan rast u kapitalnim dobicima. Naša osnovna primedba na model se odnosi na pretpostavku da su tržišni učesnici savršeno racionalni, informisani i da formiraju homogena očekivanja. Modelom se ne objašnjava proces donošenja odluka i formiranja očekivanja i ne detektuju se potencijalni psihološki i institucionalni faktori koji mogu imati značajan uticaj na odlučivanje, pa samim tim i reakciju tržišnih agenata na nove vesti. Pošto se valjanost modela procenjuje na bazi njegovih pretpostavki, zaključujemo da su dometi ovog modela, blago rečeno, limitirani.

According to the theory of rational bubbles, the bubble is present whenever asset prices progressively diverge from their fundamental value, which occurs because agents expect that asset prices will continue to grow exponentially (self-fulfilling prophecies) far in the future and consistently, which promises the realization of ever larger capital gains. In our opinion, the basic shortcoming of this theory refers to the assumption that all market agents are perfectly informed and rational and, accordingly, form homogeneous expectations. The model does not explain decision-making processes or expectation formation, nor does it detect potential psychological and institutional factors that might significantly influence decision making processes and market participants’ reactions to news. Since assumptions of the model critically determine its validity, we conclude that comprehensiveness of the rational bubble model is, to put it mildly, limited.