Even before the crisis hit in the United States, there was talk about how foolish it is to get balloon mortgages, with low teaser rates for a few years. Yet people where going for them, either because they had expectations of strong income growth, or because they were time inconsistent or very impatient. Or people do not understand the true cost of the loan.
Johan Almenberg and Artashes Karapetyan document a phenomenon that is in some ways similar in Sweden. Mortgage interest is deductible from taxes for personal loans, but not when a co=op takes a loan. Yet people seem to favor financial situations that shift debt from personal to co-op loans. On average, the equivalent of US$540 a year are left on table. This can be explained by what is termed salience of debt. People only care about the costs they directly see, and the interest payments of the co-op are not itemized in the fees. The authors survey co-op apartment owners on how they think about their finances. It turns out people a very aware of their personal finances, but completely ignorant of the co-op finances. They never considered the trade-off between personal and co-op debt. That last point may indicate that ignorance may be more important than salience, though. This is reinforced by the fact that market price do not seem to reflect the tax difference.