You posted in QBs Online, but I believe you are talking about QBs Premier Desktop.
With QBs Online I believe you can only have one Company per Acct. But with your QBs Desktop there is no limit. I would strongly suggest you create a folder for each Company to make things easier when you stop using one and go to Archive the files. When go to the File Menu and then Close Company, you'll end up on a screen that will show you the most current companies you've opened.
But if you have too many and they don't show up, you can go to the box at the bottom to Open or Restore an Existing Company and follow the prompts to search for the file you want. OR, just go to your QuickBooks Data folder (or whatever you call it) and brows for the Company you want then just click on the [company].QBW file and QBs will open.
