This paper demonstrates that in a standard flexible-price monetary model th
ere exists real indeterminacy whenever the nominal interest rate moves too
closely with either current or forecasted inflation. However, an aggressive
response to lagged inflation will ensure determinacy. These conclusions ar
e robust to a wide range of calibrations, and a monetary environment that a
llows for endogenous velocity. The results are affected by the inclusion of
investment spending in the transactions constraint. Journal of Economic Li
terature Classification Numbers: E4, E5. (C) 2001 Academic Press.