Sy_ActivityLog not showing CompanyCode field.

Hello,

I am trying to do a SQL query to see which users have had activity on a specific company ABC by doing a SQL query on the SY_ActivityLog table. 

When I do a query where CompanyCode = 'ABC', I get MOST of the users that have had activity on ABC. However, My personal user account did not show up on the list, and when I checked on the CompanyCode for my UserLogon, the field CompanyCode is blank, and a few other users who work on company ABC also have a blank space where CompanyCode should be ABC. The comanycode does, however, have TS1 in some spots where it recognized that I had activity on the test company, but nothing shows for ABC.

I would appreciate any help in this, as I have been troubleshooting for a while and I can't seem to get it.