On the Tax Calculations page there is a toggle button for Close tax year. See screenshot from this page:
The close tax year button serves one important function:
To prevent adding new transactions to previous year(s) after filing your tax forms and reports.
Adding new transactions to previous year(s) will trigger re-calculation of the cost basis for ALL transactions and may result in changes to your capital gains. To avoid this, you can (and should!) close the tax year when you are done with your tax reports for current year and want to block adding any new transactions.
How close tax year works:
- All previous year(s) must be closed before closing current year: Example: if you want to close the 2019 tax year, all previous years must be closed first (2016, 2017 and 2018)
- When year is closed, it is no longer possible to add transactions to that year (applies to API import, file upload and adding transactions manually). You will see a warning message if you try to add or import transactions to a closed tax year.
- It is not required to close the tax year when you are done with your taxes, but it is good practice and highly recommended