Thank you for your question....
Many users simply start with IAM3 by downloading their current holdings from their broker accounts, editing these to reflect accurate tax basis, and then going forward, downloading ongoing future activity. For these users of IAM3, entering historical data and past performance is not of concern. Rather, these users prefer to just set up their portfolio(s) to reflect current holdings, and then tracking activity and performance going forward from there. By the way, you can also initially create your portfolios by manually entering just your current tax lots instead of downloading if your broker is not listed in our supported broker list.
Alternatively, if you do want to measure performance based on all past historical activity, have a record of your past transactions, then you can create your portfolio(s) from inception. While this will require you to work thru past yearly broker statements from the start of the account, it does offer a more comprehensive accounting of your holdings from inception.
I suggest you visit our website video tutorials, reviewing the methods on the quick portfolio setup methods, as well as the steps for creating a historical accurate portfolio. the link is: https://www.investmentaccountmanager.com/video-tutorials.php
If you have any add'l questions, please contact our technical support team directly via email: firstname.lastname@example.org or by calling 262-241-3990.