Main Street vs. Wall Street

http://www.american.com/archive/2008/october-10-08/main-street-vs-wall-street

Harvard finance professor Robert Merton, a Nobel laureate, notes that one of the problems at large financial institutions is the gap between the executives and the financial engineers, or what I call the "suits" and the "geeks." The geeks possess knowledge that is highly specialized and extremely technical. Many suits have never even taken a course in the fundamentals of valuing complex financial instruments, even though the health of their firms depends crucially on that very issue.

Today, the suits are saying that mortgage-backed securities are undervalued, and that if the government just holds them to maturity it will make a profit. But the geeks will tell you that we cannot be certain these securities are undervalued.

The valuation of mortgage-backed securities is marked by an enormous asymmetry. If house prices rise, the security holder gains little. He or she is happy to be relieved of the risk of default, but he or she cannot share in the homebuyer's profit. On the other hand, each drop in house prices lowers the value of the security further.