FYI: AIX - not Solaris - but "old-school UNIX" in both cases.
And, yes - it is /bin/sh - which is the 'Bourne shell behavior" iirc, rather than ksh behavior, but the program is the default AIX (not solaris) ksh (see inode #)
26 -r-xr-xr-x 15 bin bin 1457 May 14 2012 hash
58 -r-xr-sr-x 1 root security 37092 Apr 25 2014 chsh
148 lrwxrwxrwx 1 root system 28 Feb 6 13:50 fcinit.sh -> /usr/sbin/rsct/bin/fcinit.sh
149 lrwxrwxrwx 1 root system 29 Feb 6 13:50 fcinit.csh -> /usr/sbin/rsct/bin/fcinit.csh
263 -r-xr-s--- 1 root system 5884 Mar 7 2014 refresh
331 -r-xr-xr-x 1 bin bin 918 May 14 2012 recsh
443 -r-xr-xr-x 1 bin bin 185344 Mar 7 2014 csh
460 -r-xr-xr-x 2 bin bin 2900986 Aug 20 2014 Rsh
460 -r-xr-xr-x 2 bin bin 2900986 Aug 20 2014 bsh
540 -rwxr-xr-x 1 root system 4690 May 6 2013 c_rehash
631 lrwxrwxrwx 1 bin bin 16 Dec 20 16:21 dsh -> /opt/csm/bin/dsh
829 -r-xr-xr-x 1 bin bin 287458 Mar 12 2013 msh
845 lrwxrwxrwx 1 root system 46 Dec 20 16:21 perfpmr.sh -> /data/prj/labserv/perf61-2014.04.30/perfpmr.sh
907 -r-sr-xr-x 2 root system 28270 Mar 8 2014 remsh
907 -r-sr-xr-x 2 root system 28270 Mar 8 2014 rsh
983 lrwxrwxrwx 1 root system 17 Dec 20 16:21 tclsh -> /usr/bin/tclsh8.4
986 -r-xr-xr-x 5 bin bin 292316 Jun 30 2014 ksh
986 -r-xr-xr-x 5 bin bin 292316 Jun 30 2014 psh
986 -r-xr-xr-x 5 bin bin 292316 Jun 30 2014 rksh
986 -r-xr-xr-x 5 bin bin 292316 Jun 30 2014 sh
986 -r-xr-xr-x 5 bin bin 292316 Jun 30 2014 tsh
1031 lrwxrwxrwx 1 root system 16 Dec 20 16:21 wish -> /usr/bin/wish8.4
AIX also supports ksh93 - but that is a different executable (different inode)
address@hidden:[/usr/bin]ls -li *ksh*
986 -r-xr-xr-x 5 bin bin 292316 Jun 30 2014 ksh
932 -r-xr-xr-x 2 bin bin 902655 Jul 11 2014 ksh93
986 -r-xr-xr-x 5 bin bin 292316 Jun 30 2014 rksh
932 -r-xr-xr-x 2 bin bin 902655 Jul 11 2014 rksh93