While the contribution deadline for making both employee and employer contributions to a solo 401k plan is always the business tax return due date including extension, the solo 401k plan will need to be opened/adopted by 12/31/2024 for new solo 401k plans where the self-employed business is a C-corporation or an LLC taxed as a C-corporation in order to preserve the right to make employee contributions for 2024 in 2025 by April 15 or October 15 if you file a timely business tax return extension.
The 2024 solo 401k setup deadline is fast approaching if your business is taxed as a C-corporation or an LLC taxed as C-corporation. If you want to make employee pretax or employee Roth solo 401k contributions for the year 2024, then the solo 401k must be adopted by 12/31/2024. This means you simply need to sign the solo 401k plan documents by 12/31/2024 so that you can make a solo 401k contribution for 2024 in 2025 by your business tax return due date plus extension.
Otherwise, if you wait to open the solo 401k (i.e., sign the solo 401k documents) until 2025, you will be able to make employer profit sharing contributions and voluntary after-tax contributions but not pre tax employee or Roth solo 401k contributions. Click here to get started.
