  Increased day-trading activity and the subsequent jump in intraday volatility
and trading volume fluctuations has raised considerable interest in models for
financial market microstructure. We investigate the random transitions between
two phases of an agent-based spin market model on a random network. The
objective of the agents is to balance their desire to belong to the global
minority and simultaneously to the local majority. We show that transitions
between the "ordered" and "disordered" phases follow a Poisson process with a
rate that is a monotonically decreasing function of the network connectivity.
