Multiple SVN Repositories or single company repository

I’ve found that having a single Subversion repository aids in:

1. Transparency: it is easier to follow what is going on, and find code even in
   projects you may not be directly involved in.
2. Maintenance: it is not necessary to create repositories every time you wish to
   create a new project, and you can delete entire projects without fear of losing
   the record from Subversion.
3. Maintenance: it is only necessary to have one repository backed up.

EDIT:
Additional reasons:

• Global revision ids – by having revision ids be global it is:
  1. Easier to communicate (e.g. in a code review request, just specify the revision
     id, without a need to specify which project).
  2. Easier to guarantee atomicity when projects have dependencies on each other.
  3. Easier to see the order of commits to different projects.