The major phases of the ownership of PSL/PSA are shown in the following table:
| Date Range | Ownership of PSL/PSA |
| 1968 - circa 1983 | University of Michigan ISDOS Project |
| circa 1983 - circa 1987 | ISDOS Inc. |
| circa 1987 - circa 1990 | Meta Systems Ltd. |
| circa 1990 - 1996 | LBMS Ltd. |
| 1996 onwards | Geoffrey Darnton |
The last release generally available commercially was PSL/PSA Version 6.0 Release 3 around September 1990.
It is expected that the Problem Statement Language will be placed in the public domain and commercial exploitation will be done by anyone who wishes to implement the language. Copyright will be retained to ensure a mechanism to certify compliance and prevent abuse.
PSL/PSA, Related Tools and associated training can be provided now on reasonable
commercial to anyone who has a need or interest to use them.