The MPS file format does not indicate whether the objective should be maximized or minimized, and each solver interprets this differently. By default, Gurobi assumes the objective function in an MPS file should be *minimized*. To instead instruct Gurobi to maximize the objective function, add the lines

OBJSENSE
MAX

to the top of the MPS file. Note that `MAX` should be indented with four spaces.

### Further information