What are the biggest tax mistakes business owners make?

Asked by: Blaze Dach DVM  |  Last update: July 3, 2026
Score: 4.1/5 (28 votes)

The biggest tax mistakes business owners make include mixing personal and business finances, inadequate record-keeping, failing to pay quarterly estimated taxes, and misclassifying employees as independent contractors. These errors often lead to missed deductions, severe IRS penalties, and audit risks.

What are common tax mistakes small businesses make?

Here are a few mistakes small business owners should avoid:

  • Underpaying estimated taxes. ...
  • Depositing employment taxes. ...
  • Filing late. ...
  • Not separating business and personal expenses. ...
  • More information:

What is the $600 rule in the IRS?

The IRS $600 rule refers to a change in reporting requirements for third-party payment apps (like Venmo, PayPal) for taxable income from goods and services, where platforms must send a Form 1099-K if you receive over $600 in a year, intended to capture gig economy/side hustle income, though delays and phased implementation have adjusted the timeline, with current rules for 2024 using a higher threshold ($5,000) before fully phasing to $600 for future years, but remember all taxable income, regardless of form, must always be reported.
 

What is a common mistake that small business owners make?

A common mistake that small business owners make is not having a budget, which causes them to overspend and wastes valuable time and money. With a budget, you can track your business' cash flow and understand how much you spend on a monthly basis.

What is the IRS $10,000 rule?

The IRS "10k rule" primarily refers to the requirement for businesses and financial institutions to report cash transactions over $10,000 by filing Form 8300 (for businesses) or a Currency Transaction Report (CTR) (for banks), under the Bank Secrecy Act. This rule helps combat money laundering, tax evasion, and terrorist financing, requiring reporting for single transactions or related transactions totaling over $10,000 in cash within a year, with penalties for non-compliance.

7 BIG Tax Mistakes Business Owners Make & How to Fix Them

39 related questions found

What is the 20k rule?

The "20k rule" refers to the traditional IRS threshold for reporting income from payment apps and online marketplaces on Form 1099-K: over $20,000 in gross payments AND more than 200 transactions in a calendar year. While a law (the American Rescue Plan) temporarily lowered the threshold to $600, recent legislation, the One Big Beautiful Bill Act (OBBBA) (OBBBA), has reinstated the $20,000/200-transaction rule for tax years starting in 2025, providing relief for casual sellers and gig workers. 

What business expenses are 100% deductible?

Yes, interest paid on business loans is generally 100% tax-deductible as a business expense. This includes interest on business credit cards, lines of credit, mortgages for business property, and equipment loans.

What is the IRS hobby income limit?

The IRS doesn't have a specific dollar limit for hobby income; instead, it focuses on profit motive: if you intend to make a profit, it's a business, but if it's for fun, it's a hobby, and you must report all income but can't deduct losses. Key is that you report all hobby income on Form 1040 as "other income," and if net earnings from self-employment are $400 or more, you owe self-employment tax, even if it's a side gig. The main difference from business is that you can't deduct hobby expenses (under current law) and must report all profits.

What qualifies as a capital improvement for the IRS?

To qualify as a capital improvement, the IRS states that the property must meet the following conditions: The improvement “substantially adds” value to your home. The improvement prolongs the useful life of the property. The improvement is permanent.

What is the $27.39 rule?

The "27.39 rule" (often rounded to $27.40) is a simple financial strategy to save $10,000 in one year by consistently setting aside $27.40 every single day, making it an achievable micro-saving habit to build wealth or an emergency fund. It turns the daunting goal of saving $10,000 into a manageable daily action, emphasizing consistency over large lump sums.

Can I gift my child $100,000 tax free?

Yes, you can give your son $100,000 tax-free in 2025 by utilizing the annual gift tax exclusion and your lifetime exemption, but you'll need to report the gift to the IRS on Form 709 since it exceeds the $19,000 annual limit, though you won't pay tax unless you exceed your much larger $13.99 million lifetime gift/estate tax exemption. The gift is considered yours (the giver) for tax purposes, not your son's. 

What is the IRS 90% rule?

The IRS will not charge you an underpayment penalty if: You pay at least 90% of the tax you owe for the current year, or 100% of the tax you owed for the previous tax year, or. You owe less than $1,000 in tax after subtracting withholdings and credits.

How far back can the IRS audit?

How far back can the IRS go to audit my return? Generally, the IRS can include returns filed within the last three years in an audit. If we identify a substantial error, we may add additional years. We usually don't go back more than the last six years.

What is the biggest mistake small businesses make?

The biggest mistake small businesses make is neglecting to plan thoroughly.

What is the #1 reason businesses fail?

1. They run out of cash. This usually happens because they do not have adequate funding from the beginning. Many owners underestimate how much it will cost and how long it will take the business to become profitable.

Are 36% to 53% of small businesses sued every year?

Yes, statistics indicate a high frequency of lawsuits, with 36% to 53% of small businesses facing legal action annually, and a significant portion (around 90%) experiencing litigation at some point in their lifespan, highlighting pervasive legal risks, often stemming from contract disputes or liability issues, making proactive legal protection essential.