How to Move Money From Your Business Checking Account to a Fidelity Solo 401(k) Without Mailing Forms or Checks

One surprisingly annoying part of using a Fidelity Solo 401(k) is figuring out how to actually move money from your business checking account into the plan.

Fidelity lists several contribution methods for its Self-Employed 401(k), including EFT from a bank, transfer from another Fidelity account, mobile check deposit, bank wire, bill pay from a non-Fidelity account, and direct deposit.  Fidelity also supports mailing a check with a 401(k) contribution remittance form, but that is not my favorite workflow for busy physicians and CRNAs.

Here is the cleaner method I found (I call it, the KENdelity Workaround...ok I'll stop):

The easiest workflow: use business bank bill pay

1. Log in to Fidelity and pull the routing and account numbers for each Fidelity Solo 401(k) account here:

   https://digital.fidelity.com/ftgw/digital/direct-deposit-information/

2. You should have separate account information for the pretax Solo 401(k) and Roth Solo 401(k), if you opened both (or 3 for custom solo 401k plans).

3. Log in to your business checking account.

4. Add each Fidelity Solo 401(k) account as a bill-pay payee/vendor.

5. Set up one-time or recurring payments from the business checking account to the appropriate Fidelity account.

6. Label each transfer clearly in your records, such as:

   • “2026 employee deferral – pretax Solo 401(k)”

   • “2026 employee deferral – Roth Solo 401(k)”

   • “2026 employer profit-sharing contribution”

     
     

This avoids the clunky process of mailing contribution forms and checks, and it creates a clean payment trail from the business account.

Important note for S-corp owners

If your physician or CRNA business is taxed as an S corporation, do not treat Solo 401(k) contributions casually. Employee deferrals should be supported by payroll records and a salary deferral election. Fidelity says incorporated businesses must make a written salary deferral election before deferrals begin and before

the end of the business tax year (we manage all that).

Also, Roth Solo 401(k) contributions are employee salary deferrals only. Fidelity states that only employee salary deferral contributions can be made into the Roth Self-Employed 401(k).  Employer profit-sharing contributions generally go to the pretax side.

Why this matters

A Solo 401(k) is one of the best retirement planning tools for independent physicians and CRNAs because it can allow large contributions, pretax tax deductions, Roth flexibility, and better planning options than a SEP IRA in many cases.

But the plan only works if the money actually gets contributed correctly and on time. Fidelity notes that, for ongoing plans, employee salary deferrals and company profit-sharing contributions generally must be completed by the business’s tax filing deadline, including extensions.

Final tip

Before automating payments, confirm three things:

1. The correct Fidelity account number for pretax vs. Roth.

2. The correct contribution type and tax year.

3. That your payroll, salary deferral election, and bookkeeping match the transfers.

   
   

This is exactly the type of setup we help independent physicians and CRNAs build into their accounting system so retirement contributions, payroll, tax projections, and business cash flow all work together. You can learn more about our tax and accounting plans here: https://www.keneremita.com/tax-and-accounting-integrated-plan-pricing