# Tag Info

It is not negative returns that are an issue. Assume the following prices in two periods: $P_o = 100$ ; $P_1 = 99$ Standard percent calc: $$\frac{P_1}{P_0}-1 = -0.01$$ which is -1% . Using the natural logarithm you get $$ln(99)-ln(100) = -0.01005$$ which is essentially identical. Negative prices are an issue - but these are not observed for many economic ...