  We analyse two classes of $(1+2)$ evolution equations which are of special
interest in Financial Mathematics, namely the Two-dimensional Black-Scholes
Equation and the equation for the Two-factor Commodities Problem. Our approach
is that of Lie Symmetry Analysis. We study these equations for the case in
which they are autonomous and for the case in which the parameters of the
equations are unspecified functions of time. For the autonomous Black-Scholes
Equation we find that the symmetry is maximal and so the equation is reducible
to the $(1+2)$ Classical Heat Equation. This is not the case for the
nonautonomous equation for which the number of symmetries is submaximal. In the
case of the two-factor equation the number of symmetries is submaximal in both
autonomous and nonautonomous cases. When the solution symmetries are used to
reduce each equation to a $(1+1)$ equation, the resulting equation is of
maximal symmetry and so equivalent to the $(1+1)$ Classical Heat Equation.
