In this talk we discuss ergodic optimization problems for subadditive
sequences of functions
on a topological dynamical system. We show that for $t\rightarrow
\infty$ any accumulation point
of a family of equilibrium states is a maximizing measure.
We also show that the Lyapunov exponent and entropy of equilibrium
states converges in the limit $t\rightarrow \infty$
to the maximum Lyapunov exponent and entropy of maximizing measures.