Sunday, October 27, 2013

Fact-checking The Economist

Here is a question for students who are learning about compounding.  What is wrong with the following passage from The Economist magazine?
Investors who bought Treasury bonds in 1946, when yields were around current levels, did not suffer a formal default. But over the following 35 years they lost money in real terms at a rate of 2% a year. The cumulative real loss was 91%. By that standard, Greek creditors, who recently suffered a 50% loss via default, were lucky.
Answer: The second number is inconsistent with the first.  Note that .98^35=.49, so we get only a 51 percent cumulative loss.

In fact, the price level from 1946 to 1981 rose by a factor of about 5, so holding currency with a zero nominal return led to a real loss of only about 80 percent.