  We present a exactly soluble model for financial time series that mimics the
long range volatility correlations known to be present in financial data.
Although our model is `monofractal' by construction, it shows apparent
multiscaling as a result of a slow crossover phenomenon on finite time scales.
Our results suggest that it might be hard to distinguish apparent and true
multifractal behavior in financial data. Our model also leads to a new family
of stable laws for sums of correlated random variables.
