Form 5500-EZ
Individuals with Solo 401k plan(s) with $250,000 or more in asset value as of December 31 of each year are likely required to file Form 5500-EZ for that year, by July 31 of the following year for calendar year plans. Solo 401k plans that are terminating are also required to file Form 5500-EZ, regardless of asset value.
As Plan Administrator you are ultimately responsible for the timely and accurate filing of Form 5500-EZ if required, along with all other tax filings for your Solo 401k plan.
Form 5500-EZ and more information on how to file is available from the IRS here: https://www.irs.gov/forms-pubs/about-form-5500-ez
Plan Information
You'll need your Solo 401k plan information to complete the form, which can be found by clicking on your profile icon in the top right -> Settings -> Accounts, or by clicking here: https://app.carry.com/settings/accounts
For IRS plan codes for a one-participant Carry Solo 401k plan, you should use: 2E, 2J, 3B, 3D
The IRS opinion letter for Carry plans is dated 06/30/2020 and the serial number is: Q704115a
Asset Value
To prepare an annual (non-terminating) Form 5500-EZ, you'll need the asset value of your plan as of 12/31, as well as loan balances and participant counts. Typically, the participant count for a Solo 401k would be 1, but if you have a spouse or any other owner-employees on the Solo 401k plan they may count.
Asset value as of 12/31 can be determined from your statements, available by clicking on your profile icon in the top right -> Documents -> Statements, and selecting Solo 401k and the previous year. If you have multiple tax types, you should include the asset value from all Solo 401k accounts.
If you hold off-platform assets, such as alternative assets or accounts with Kraken, Solera, or other financial institutions, that are Solo 401k investments (or accounts in the name of the Solo 401k plan), you will likely also have to value and include those assets.
Other Information
If you have any questions, you should reach out to an accountant who is familiar with employer benefit plan tax forms, or taxes for Solo 401k plans.