The Tax Checklist Your CPA Might Not Send You

As I'm sure everyone knows, the tax deadline of April 15 is quickly approaching.

I frequently help our clients review their tax returns before they file them.

This is not only to find potential mistakes, which is certainly possible, but also to make sure there are no planning opportunities that are missed.

With that in mind, I wanted to share my top 10 mistakes or omissions that I frequently see.

Please note this applies to clients who prepare their tax returns on their own and also those who work with a professional preparer.

So please don't skip this list even if you work with a good CPA!

1. Missing the IRA Contribution Window

This is a basic issue but almost every year at least someone will miss this one.

You have until April 15 of the current year to contribute to an IRA for the previous year.

Many people assume they cannot contribute if they do not have a personal income.

However, if you are married, you can potentially fund a spousal IRA based on your partner's earnings, subject to income phase-out thresholds.

Additionally, if you think you can't contribute to an IRA at all because of the income threshold, think again.

Anyone with earned income can make a nondeductible contribution to a traditional IRA and potentially even do a backdoor Roth contribution to take advantage of tax-free growth.

2. Forgetting Solo 401k Contributions

When compared to "traditional" or employer-provided 401k accounts, as a solo 401k plan owner, you actually have until April 15 or even the extension date to make the employer portion of your 401k contributions.

This gives you additional flexibility if you have cash flow issues or receive your income in a "lumpy" fashion throughout the year.

Important note for S-Corp owners. The rules differ depending on the contribution type.

Employee salary deferrals must be withheld from your W-2 paycheck through payroll before December 31.

Employer profit-sharing contributions, however, are made directly by the S-Corp to the plan and can be funded after year-end, up to your corporate tax filing deadline (March 15 or September 15 with extension).

3. Missing Catch-Up Contributions

If you are age 50 or older, you can contribute more to your retirement plans.

These extra amounts can significantly boost your savings as you approach retirement.

Qualified plans through an employer, like 401k's, 403b's and 457 plans, only allow for catch-up contributions to be made via payroll and thus have a year-end deadline.

But IRA accounts and solo 401k's allow for catch-up contributions to be made by the tax deadline.

Do not leave this extra savings on the table!

4. Underfunding Your Health Savings Account

The Health Savings Account (HSA) is a rare tool that offers a triple tax benefit.

Your after-tax, non-payroll 2025 contributions can be made right up until the April 15 deadline.

These contributions lower your taxable income and the money grows tax-free.

If you had a high-deductible health plan last year, check your records to see if you can still add funds to reach the maximum limit.

And don't forget, every person who contributes to or takes a distribution from an HSA must include Form 8889.

This form reports your total contributions and ensures your withdrawals were used for qualified medical expenses.

Missing this form can trigger a notice from the IRS and potential penalties.

5. Backdoor Roth Conversion and Overlooking Form 8606

If you completed a backdoor Roth conversion, your tax return must include Form 8606.

This form is essential because it tracks your after-tax basis.

Without it, the conversion will likely be treated as a regular contribution or recharacterization and will be taxable to you.

This is a very common issue!

6. Forgetting to Take Your Required Minimum Distribution (RMD)

If you missed a required minimum distribution and believe you qualify for a penalty waiver, you likely need Form 5329.

This form allows you to report additional taxes or request an exception for early withdrawals.

The bottom line is you really don't want to miss your RMD! But if it happened for any reason, you want to fix this issue as soon as possible.

7. Failing to Report All Income from Your 1099 Forms

The IRS receives copies of every 1099 form sent to you.

With the rise of digital payments and having accounts at multiple brokerages, it's easy to miss at least one Form 1099.

I can tell you we have clients who have to collect and report more than a dozen different 1099s each year.

What can you do about it? Stay organized and try to consolidate your accounts as much as possible.

8. Confusing the Extension to File with an Extension to Pay

If you cannot finish your return by April 15, you can file for a six-month extension.

However, this only gives you more time to file the paperwork.

It does not give you more time to pay the taxes you owe.

You should still estimate your balance and send a payment by the deadline to avoid interest and penalties.

This is a very common confusion, especially for those who haven't been dealing with their taxes for a long time.

9. Simple Clerical Errors

These include not triple-checking that your name, Social Security number and address are all entered correctly.

It also includes not entering your routing or account number correctly for any refunds or payments.

And even worse, this includes not signing the final signature box.

It sounds basic, but many returns are rejected simply because they were not signed.

10. Treating Tax Planning as a Seasonal Event

Here is the reality.

If you wait until the spring to think about taxes, you have already missed most opportunities.

Even the best CFP or CPA can only do so much when you reach out a few weeks before the deadline.

Real planning happens throughout the year, giving you time to adjust your income or move assets before the calendar turns.

A proactive approach is always better than a reactive one.

As Benjamin Franklin wisely noted, taxes are certain, so you might as well plan for them.