  Persistence is studied in a financial context by mapping the time evolution
of the values of the shares quoted on the London Financial Times Stock Exchange
100 index (FTSE 100) onto Ising spins. By following the time dependence of the
spins, we find evidence for power law decay of the proportion of shares that
remain either above or below their ` starting\rq values. As a result, we
estimate a persistence exponent for the underlying financial market to be
$\theta_f\sim 0.5$.
