A Fund Manager investment is any stock, mutual fund, bond, option, etc. An investment contains the transaction and pricing history for the assigned stock or fund. Each investment is saved to its own file. Investments are saved as files with the extension of *.dat. Investments can be added into sub-portfolios. Investments can be added into any number of sub-portfolios.
Each investment file can have an unlimited number of pricing and transaction data.
With Fund Manager you can track an unlimited number of investments, but you can only have a certain number open at once. This limit to the number of open investments varies depending on the version of Fund Manager:
Investment Properties Dialog