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vnc-
Om det nu är så uppenbart vad en bubbla är så borde det finns en enkel definition som de flesta håller med om. Det finns ju mängder med andra ekonomiska teorier och modeller som i princip alla har samsyn på.
Vissa säger att 10% nedgång är en korrektion. Vissa säger att det är en sprucken bubbla. Du pratar om att det krävs 20-30% för att få kalla det sprucken bubbla. Andra i den här tråden pratar om 50-75%. Hur ska vi ha det? Du kan gärna få förklara, med både matematiska och ekonomiska förklaringsmodeller, varför det bör klassas som en sprucken bubbla vid 20-30% nedgång.
Ja, det finns ju att läsa om frågan:
Housing bubble definition
Most research papers on housing bubbles uses standard asset price definitions. There are many definitions of bubbles. Most of them are normative definitions, like that of Stiglitz (1990),[3] that try to describe bubbles as periods involving speculation, or argue that bubbles involve prices that cannot be justified by fundamentals. Examples are Palgrave (1926),[4] Flood and Hodrick (1990),[5] Shiller (2015),[6] Smith and Smith (2006)[7] and Cochrane (2010).[8]
Stiglitz’ definition is: “…the basic intuition is straightforward: if the reason that the price is high today is only because investors believe that the selling price will be high tomorrow—when ‘fundamental’ factors do not seem to justify such a price—then a bubble exists.” (Stiglitz 1990, p. 13)[3]
Lind (2009)[9] argued that we needed a new definition of price bubbles in the housing market, an “anti-Stiglitz” definition. His point is that traditional definitions such as that of Stiglitz (1990),[3] in which bubbles are proposed as arising from prices not being determined by fundamentals, are problematic. This is primarily because the concept “fundamentals” is vague, but also because these type of nominal definitions typically do not refer to a bubble episode as a whole—with both an increase and a decrease of the price. Lind claims that the solution is to define a bubble by focusing only on the specific development of prices and not on why prices have developed in a certain way. The general definition of a bubble would then simply be: “There is a bubble if the (real) price of an asset first increases dramatically over a period of several months or years and then almost immediately falls dramatically.” (Lind 2009, p. 80)[9]
Inspired by Lind (2009),[9] Oust and Hrafnkelsson (2017) created the following housing bubble definition: “A large housing price bubble has a dramatic increase in real prices, at least 50% during a five-year period or 35% during a three-year period, followed by an immediate dramatic fall in the prices of at least 35%. A small bubble has a dramatic increase in real prices, at least 35% during a five-year period or 20% during a three-year period, followed by an immediate dramatic fall in the prices of at least 20%.”[10]
Vissa delar stämmer absolut in på den svenska bostadsmarknaden. Det som saknas är mer direkt spekulation, dvs att det köps och hålls bostäder enbart för att kunna tjäna på prisuppgången.
