Abstract
The econometric analysis of UK M0 has, so far, been confined to linear models. Using quarterly data over the period 1970:4–1997:2 in a single-equation money demand system, this article shows that a linear error-correction equation of the demand for UK M0 contains significant non-linearity and parameter non-constancy of smooth transition regression (STR) type. A constant-parameter exponential STR (ESTR) equation is then estimated, suggesting that interest rate changes have been an important factor in explaining fluctuations in the demand for UK M0.