Any number!  Each company is licensed individually.  You will need to purchase a license key for each company that you wish to create.  Contact Sales for a quote.

AcctVantage Client licenses are bound to your AcctVantage Server, not a specific company. Meaning you do not need to specify which company an AcctVantage Client license belongs to.

Let's say you have a 10 user AcctVantage license for a single company today.  When you add a second company, you do not need to add more AV Client user licenses.  You will still be allowed a total of 10 connections to your Server.  You could have 8 active connections in Company A and 2 active in Company B.  Or 6 in Company A and 4 in Company B. So long as you do not exceed 10 total combined connections you will not need to purchase anything additional.

The answer here is simple.  None.  Every record in your AcctVantage database will be marked with a Compay ID.  There are no "shared" records at all among your different company files.

The helps to prevent blurred lines for tax, audit and legal purposes.

While no records are shared, AcctVantage Support can help you with consolidated financial reporting and operational reports that cross company files.  Contact Support for assistance.

No.  There is a clear division between company records, including your User records.  You will need to create unique User records in each company data file for each person that requires access.

For example, if you have an AP clerk that will access both company files, that person will have two (2) unique log in names and passwords, 1 for each company.

Each time you log into AcctVantage Server, you will be asked which company you wish to connect to.

If you are already logged into a company, and wish to switch to a different company, you do not need to log out of AcctVantage Client.  Select Tools > Change User to log in and select the desired company.