9 Tax Filing Mistakes Real Estate Investors Make Every Year

With tax season approaching, many real estate investors focus on strategies to reduce their tax bill: short-term rentals, cost segregation, or real estate professional status (REPS). But there’s another issue that often costs investors just as much money: tax filing mistakes.

According to Thomas Castelli and Nathan Sosa, a large percentage of the tax returns they review each year contain significant errors or missed opportunities. Some mistakes lead to penalties and interest, while others quietly cost investors tens of thousands in lost tax savings. Here are some of the most common tax filing mistakes they see—and how to avoid them.

1. Reporting Short-Term Rentals on Schedule C Instead of Schedule E

One of the most common errors involves misreporting short-term rental income. Many general CPAs incorrectly report Airbnb income on Schedule C, which is used for active businesses. The issue is that Schedule C income is subject to self-employment tax (15.3%). Most short-term rentals should instead be reported on Schedule E, which avoids self-employment tax. Schedule C is only appropriate if substantial services are provided, such as daily housekeeping, meals or catering, concierge services, or transportation—similar to a hotel. Simply being available to guests or providing occasional assistance does not qualify. Misclassification can create unnecessary tax liability.

2. Not Filing a Tax Extension

Many investors assume filing an extension increases audit risk, but extensions are very common—especially for real estate investors with complex returns. Delays often occur due to K-1 timing, partnership filings, multi-entity structures, and additional documentation requirements. The key rule is that extensions must be filed before the tax deadline. If not, penalties can apply immediately. This is particularly important for partnerships and S-corporations, which have earlier deadlines than individual returns.

3. Forgetting That Extensions Don’t Extend Payment Deadlines

An extension gives you more time to file—but not more time to pay. If taxes are owed, investors should make an estimated payment by the original filing deadline. Failing to do so can result in interest charges and underpayment penalties. While the interest rate may be relatively low, it’s still an unnecessary and avoidable cost.

4. Missing Deductions Due to Poor Recordkeeping

Another common issue is missing deductions entirely. Investors often overlook expenses like property taxes, insurance premiums, repairs and maintenance, management fees, and utilities. This typically happens when relying on manual spreadsheets or incomplete records. Better systems—such as bookkeeping software like QuickBooks, dedicated business credit cards, and regular bookkeeping reviews—can help ensure deductions are properly tracked and claimed.

5. Electing Out of Bonus Depreciation (Often Permanently)

This is one of the most expensive mistakes investors can make. When filing a return, a CPA may elect to opt out of bonus depreciation, which can sometimes be irreversible. Doing so may eliminate the ability to later perform a retroactive cost segregation study, potentially costing tens of thousands in missed deductions. While there are situations where electing out makes sense, it should never be done without careful planning.

6. Missing Real Estate Professional Status Grouping Elections

If you qualify for real estate professional status (REPS), you must also meet material participation requirements. Without a grouping election, you must meet these requirements for each property individually—something that becomes extremely difficult for larger portfolios. Grouping elections allow you to treat all rental properties as a single activity, making it much easier to qualify. Failing to make this election can significantly reduce the tax benefits of REPS.

7. Passive Loss Carryforwards Not Being Tracked

Passive losses are often suspended when they can’t be used immediately and are carried forward to future years using Form 8582. These losses can later offset passive income or reduce taxable gain when a property is sold. However, if they are not properly tracked and carried forward, they may be lost entirely—resulting in missed tax savings when you need them most.

8. Incorrect Entity Reporting

Incorrect entity classification and reporting is another frequent issue. Common mistakes include treating a multi-member LLC as a single-member entity, failing to file partnership returns, misreporting ownership structures, or placing rental properties into S-corporations improperly. Adding a spouse or partner to an LLC can unintentionally create a partnership filing requirement. Missing those filings can trigger penalties, and holding rental real estate in an S-corporation is often problematic and should be carefully evaluated.

9. Not Filing Tax Returns at All

One of the most surprising mistakes is simply not filing tax returns. This often happens when investors are waiting on K-1s or assume they don’t owe taxes. However, failing to file can lead to penalties, interest, audit exposure, and issues when applying for financing. Many investors eventually have to file multiple years of returns at once, which becomes far more complicated. Staying current with filings is always the safer approach.

Bonus: Missing Partial Asset Dispositions

A more advanced but frequently overlooked opportunity involves partial asset dispositions (PADs). When components of a property—such as roofs, HVAC systems, appliances, or structural elements—are replaced, the remaining basis of the old component may be deductible. Many general CPAs miss this entirely, and in some cases, identifying missed PADs has generated six-figure deductions for investors.

Why Real Estate Specialists Matter

Many of these mistakes occur because general CPAs are not familiar with the nuances of real estate taxation. Real estate investors face unique complexities involving depreciation strategies, entity structuring, material participation rules, passive activity limitations, and cost segregation opportunities. Working with a tax professional who specializes in real estate can help ensure these strategies are properly implemented and that costly mistakes are avoided.

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Disclaimer: This podcast summary was generated from the transcript and may contain some errors or miss key points from the audio recording.