The Most Expensive S-Corp Mistakes

Mistake #1: No owner payroll, lots of distributions

The single biggest audit trigger. If your S-Corp distributed money to the owner and the owner did real work, the IRS expects W-2 wages. Owners who take $0 in salary but $150,000 in distributions are the textbook target for reclassification.

Fix: set up real payroll on day one. See our reasonable compensation guide and owner salary setup.

Mistake #2: Commingling business and personal funds

Running personal expenses through the business checking account or treating distributions like an ATM destroys the corporate veil and makes shareholder basis impossible to track. In an audit, commingling is often what tips an examiner from "let me check this" to "let me dig in."

• Use a dedicated business bank account and credit card
• Pay yourself salary via payroll and distributions via clearly-labeled transfers
• Reimburse personal expenses through an accountable plan, not by running them through the business directly

Mistake #3: Missing or late Form 1120-S

S-Corps file Form 1120-S annually by March 15 (or September 15 with extension). The penalty for late filing is $245 per shareholder per month, up to 12 months. A two-shareholder S-Corp filed six months late owes nearly $3,000 in penalties alone — even if you owe no tax.

Mistake #4: Mishandled shareholder loans

Pulling money out of the S-Corp and calling it a "loan" without proper documentation is one of the IRS's favorite reclassification targets. A real loan needs:

• A signed promissory note with a stated interest rate at or above the AFR
• A defined repayment schedule
• Actual repayments documented in the books
• Treatment as a loan on the balance sheet — not as a distribution

Without those, the IRS will recharacterize the "loan" as either wages or a taxable distribution.

Mistake #5: No reasonable-comp documentation

Setting your salary at $36,000 because that's what your friend pays themselves is not a defense. Document your salary methodology with:

• Bureau of Labor Statistics or RC Reports data for your role and region
• Hours worked per week
• Specific responsibilities (CEO duties vs. technical vs. sales)
• Annual review and update as the business grows

Mistake #6: Forgetting state-level S-Corp elections and multi-state payroll

A federal S-Corp election does not automatically apply at the state level. New York, New Jersey, and a handful of other states require a separate state election. And once you have employees (including the owner) working in multiple states, you must register and run payroll in each one. See multi-state payroll for the full breakdown.

Mistake #7: Not tracking shareholder basis

Distributions are tax-free only up to your basis. Once you exceed it, the excess becomes a capital gain. Owners who never track basis often discover years of unreported gains during a due-diligence sale or an audit.

How GuidedLedger prevents these mistakes

We set up payroll, build the chart of accounts to separate salary from distributions, document your reasonable comp methodology, maintain a basis schedule, and make sure your 1120-S is filed on time every year.

Frequently Asked Questions

Keep reading

• Reasonable compensation rules
• How to elect S-Corp status
• Revoking your S-Corp election
• Owner salary setup
• Multi-state payroll