When most people in King County hear the term “tax basis,” they assume it only matters when they sell a home or investment. In reality, tax basis affects capital gains taxes, inheritance planning, real estate investments, small business ownership, and even some retirement and stock transactions.
For residents of King County, where property values have risen dramatically over the past decade, understanding basis can potentially save tens or even hundreds of thousands of dollars in taxes.
What Is Tax Basis?
Tax basis is generally what you have invested in an asset for tax purposes.
For example:
- You buy a home for $600,000.
- You spend $100,000 on qualifying improvements.
- Your adjusted tax basis becomes $700,000.
If you later sell the property for $1,200,000, your gain is generally calculated using the difference between the sale price and your adjusted basis.
Why It Matters So Much in King County
Many homeowners in areas such as Seattle, Bellevue, Redmond, and Kirkland purchased homes years ago that have appreciated substantially.
Consider a homeowner who:
- Purchased a home for $350,000 in 2005.
- Sells it today for $1.4 million.
Without proper basis documentation, they could pay significantly more capital gains tax than necessary.
Maintaining records of improvements such as:
- Room additions
- Major remodels
- New roofs
- HVAC systems
- Kitchen renovations
- Certain landscaping improvements
can increase basis and reduce taxable gain.
Basis and Inherited Property
One of the most important tax rules for King County families involves inherited assets.
When someone inherits property, the asset typically receives a “step-up in basis” to its fair market value at the date of death.
Example:
- Parent purchased a Seattle home in 1985 for $150,000.
- Home is worth $1.8 million when inherited.
- Heirs generally receive a basis of approximately $1.8 million.
If the property is sold shortly thereafter for $1.85 million, only a relatively small gain may be taxable.
Without the step-up rule, heirs could face taxes on over $1.6 million of appreciation.
This makes basis tracking a critical component of estate planning for many King County families.
Basis for Rental Properties
Many King County residents own rental homes, duplexes, or investment properties.
Basis affects:
- Depreciation deductions
- Gain on sale
- 1031 exchange calculations
- Passive activity losses
A common mistake is failing to properly separate:
- Land value
- Building value
- Capital improvements
This can lead to incorrect depreciation and potential IRS issues later.
Basis in Stocks and Investments
Tax basis also applies to:
- Individual stocks
- Mutual funds
- ETFs
- Employee stock purchase plans
- RSUs and stock options
This is especially relevant for employees of major regional employers such as Microsoft and Amazon, where equity compensation can create complicated basis calculations.
If basis is reported incorrectly, investors can end up paying tax twice on the same income.
Basis and Washington’s Capital Gains Tax
Washington’s capital gains tax can apply to certain gains from the sale or exchange of long-term capital assets above the annual exemption threshold.
Because gain is determined using basis, accurate basis records are essential for calculating potential Washington capital gains tax exposure as well as federal capital gains taxes.
Basis and Small Business Owners
For owners of S corporations, partnerships, and LLCs, basis can determine:
- Whether losses are deductible
- Whether distributions are taxable
- Gain or loss when selling the business
- Tax consequences when a business closes
Many business owners discover basis issues only when preparing a tax return or selling the company.
Common Basis Mistakes
The most common issues tax professionals see include:
- Missing records for home improvements
- Incorrect rental property depreciation schedules
- Failure to document inherited property values
- Double-counting or undercounting stock basis
- Not tracking partnership or S-corporation basis annually
- Losing records after moving or changing accountants
Why Basis Planning Is Becoming More Important
In King County’s high-appreciation environment, basis has become one of the most valuable tax concepts for homeowners, investors, and business owners. A well-documented basis can reduce taxable gains, support deductions, and prevent costly disputes with tax authorities.
For many families, basis records are worth preserving just as carefully as wills, trusts, property deeds, and business ownership documents because they can have a direct impact on future tax liability. For more please give this office a call (206) 838-3800 or email info@ygacpa.com.