  We have completed our observational program to search for wide binary systems
with non-coeval components in the southern sky and report our results here. The
final set of four systems was spectroscopically investigated in this paper. No
binary systems with components of different ages were found among them. Taking
into account our previous studies, we estimate the fraction of such binaries
(i.e., binaries formed, presumably, by capture) not higher than 0.06~\%. The
study will be continued on the northern sky.
