Given that the Poisson event occurs (i.e., some important information on the
stock arrives), then there is a ‘drawing’ from a distribution to determine the
impact of this information on the stock price. I.e., if S(r) is the stock price at
time t and’Y is the random variable description of this drawing, then, neglecting
the continuous part, the stock price at time t +/I, S(! +A), will be the random
variable S(r+h) = S(r) Y, given that one such arrival occurs between I and
(!+h). It is assumed throughout that Y has a probability measure with compact
support and Y 2 0. Moreover, the { Y) from successive drawings are independently
and identically distributed.