Cost Basis Step-Up Explained (San Diego Living Trust Guide)

If you own a home, rental property, or stock accounts, one of the most important estate planning concepts to understand is the cost basis step-up (also called a basis step up or step-up in cost basis).

Throughout the estate planning process, many San Diego families focus on avoiding probate—but in reality, one of the biggest financial benefits of good estate planning is reducing taxes for your children and beneficiaries.

A cost basis step up can save your family thousands—or even hundreds of thousands—of dollars in capital gains taxes.

In this guide, we’ll explain what a cost basis step-up is, how it works, and why it matters for San Diego families.

What Is Cost Basis?

Cost basis is essentially the original value of an asset for tax purposes. In most cases, it will be the purchase price of the property, i.e. what did you buy real estate or stocks for.

When you sell an asset, your taxable gain is usually calculated as:

Sale price – cost basis = capital gain

That capital gain may be subject to state and federal capital gains taxes.

Example: Cost Basis for a Home

If you bought your home for $350,000 and later sell it for $1,200,000, your capital gain is generally:

$1,200,000 – $350,000 = $850,000 gain

Depending on exemptions and tax laws, all or a portion of that gain would be taxable.

What Is a Basis Step Up?

A basis step up occurs when someone inherits an asset after the owner dies. In many cases, the IRS allows the beneficiary to receive the asset with a new cost basis equal to the asset’s fair market value on the date of death.

This is called a step-up in cost basis.

Instead of inheriting the original purchase price, the beneficiary inherits the value at the time the owner passed away.

This can dramatically reduce capital gains taxes. If the beneficiary sells the asset before it appreciates, there will be no capital gains taxes at all! If the beneficiary sells the asset later, the profit subject to the capital gains taxes would only be the difference between the sales price and the fair maker value at the previous owner’s passing.

Step-Up in Cost Basis Example (Family Home)

Let’s say:

Parents bought a home in San Diego for $200,000
The home is now worth $1,500,000
The parents pass away and leave the home to their child

If a step-up applies, the child’s new cost basis will be $1,500,000.

So if the child sells the home soon after inheriting it for $1,500,000, the gain will most likely be $0.

Without the step-up, the child could owe capital gains tax on:

$1,500,000 – $200,000 = $1,300,000

That is an enormous tax difference.

Why Cost Basis Step-Up Matters for Middle-Class Families

Many people assume that only wealthy families need estate planning. But in San Diego County, even middle-class families often own:

A primary residence
A rental property
A brokerage account
Stocks or mutual funds
A small business

Over time, these assets may appreciate significantly.

That means the cost basis step up can become one of the biggest financial benefits you leave behind.

What Assets Qualify for a Cost Basis Step-Up?

A step-up in basis often applies to many common assets, including:

Primary residences
Rental properties
Vacation homes
Stocks
Mutual funds
ETFs
Brokerage accounts
Business interests

However, not every asset receives a step-up. Some assets have different rules, for example retirement accounts.

This is why it is important to work with a qualified estate planning attorney.

Cost Basis Step-Up for a Family Home

A family home is often the biggest asset passed down to children. If the home has been owned for decades, the appreciation can be substantial.

Why It Matters in San Diego

Homes in many San Diego neighborhoods—such as Carmel Valley, La Jolla, Del Mar, Clairemont, and Mira Mesa—have risen significantly in value over the past 20–40 years.

This means families who bought homes for $250,000 may now own homes worth $1.5 million or more.

A cost basis step-up may protect children from huge capital gains tax bills later.

Cost Basis Step-Up for Rental Property

Rental real estate is another area where step-up in basis is extremely important.

Rental properties often have:

Significant appreciation
Depreciation deductions over time
Complex tax reporting issues

A cost basis step up addresses all of the above by significantly reducing tax liability for the beneficiary inheriting the property.

Cost Basis Step-Up for Stocks and Investment Accounts

Stocks and brokerage accounts are commonly inherited assets.

If a parent bought stocks years ago and they appreciated, heirs may benefit from a step-up in cost basis.

Example:

Parent purchased $50,000 in stock
Stock is now worth $300,000
Parent passes away
Child inherits the stock with stepped-up basis

If the child sells soon after inheriting, there will likely be no taxable gain.

This is one of the easiest ways families can unintentionally lose money if they gift stock during life instead of planning properly.

What Happens If You Gift an Asset During Your Lifetime?

This is where many families make mistakes.

If you gift property while alive, your child typically receives your original cost basis, not a stepped-up basis.

This means gifting can transfer a major capital gains tax burden to your children. The value of the gift also counts against your lifetime gift and estate tax exemption and you will be required to file a gift tax return for all gifts above the annual gift tax exclusion ($19,000 per recipient in 2026).

Example: Gifting a Home

You bought your home for $300,000
It is now worth $1,400,000
You gift it to your child

Your child will inherit your $300,000 basis.

If they later sell for $1,400,000, they will owe capital gains tax on $1,100,000.

This can be financially devastating, especially for middle-class families.

How to Get a Cost Basis Step-Up

Many people ask: how do you get a cost basis step up?

In most cases, a step-up happens when assets are transferred at death, not during lifetime.

Here are common ways the step-up is achieved:

1. Inheritance Through a Living Trust

A properly drafted trust often allows assets to transfer to beneficiaries after death while still preserving the step-up in basis.

This is why many families ask about:

living trust cost basis step up

A trust does not automatically “create” a step-up—but a properly structured estate plan often allows the step-up rules to apply.

2. Inheritance Through Probate

Even if someone does not have a trust, heirs may still receive a step-up if the asset is inherited through probate.

However, probate can be expensive, time-consuming, and stressful.

Many families use a trust to avoid probate while still preserving tax advantages.

3. Joint Ownership (Sometimes)

In certain cases, spouses may receive a step-up when one spouse dies, especially in community property states like California.

But joint ownership can be complicated, and the rules depend on how title is held.

This is why it’s important to consult with a qualified estate planning attorney before changing deeds.

Does a Living Trust Provide a Cost Basis Step-Up?

A common question is:

Does a living trust get a step-up in basis?

In many cases, yes—assets held in a revocable living trust may still qualify for a step-up in cost basis because the trust is treated as part of the person’s estate.

This is one of the major benefits of using a living trust for estate planning.

However, not all trusts are the same. The structure matters.

If you are working with a living trust attorney in San Diego, they can ensure your trust is drafted correctly and properly funded.

Why Step-Up in Basis Is Especially Important Under Prop 19

Many California families want to transfer their home to their children to protect property tax benefits under Proposition 19.

But they may accidentally trigger a different financial problem:

Losing the Step-Up in Basis

Families sometimes add children to title or gift property too early, believing it will help avoid probate or preserve property taxes.

But doing so may eliminate the step-up in basis and create massive capital gains taxes later.

For many middle-class families, capital gains tax consequences can be far more damaging than property taxes.

Common Mistakes Families Make With Step-Up in Basis Planning

Here are some of the most common mistakes we see:

Mistake #1: Adding a Child to the Deed Without Legal Advice

This can trigger:

reassessment issues
gift tax reporting
loss of control
creditor exposure
complications if the child divorces or is sued

Mistake #2: Gifting Rental Property Too Early

Rental properties often have major appreciation and depreciation history, making tax consequences complex.

Mistake #3: Assuming a Trust Automatically Handles Everything

A trust must be properly structured and properly funded. If the home is not transferred into the trust correctly, probate may still be required.

Mistake #4: Not Coordinating Estate Planning With Tax Strategy

Estate planning and tax planning must work together. A good estate plan should help preserve wealth, not accidentally create tax burdens.

Should Middle-Class Families in San Diego Consider a Living Trust?

The answer is yes.

A living trust may help:

avoid probate
transfer assets efficiently
protect beneficiaries
preserve cost basis step-up opportunities
reduce legal conflict after death

If you own a home in San Diego County, a living trust is often one of the most practical estate planning tools available.

Families in Carmel Valley, in particular, often have significant home equity and investment accounts, making proper planning especially important.

If you are searching for a living trust lawyer in Carmel Valley, it may be worth scheduling a consultation to understand your options.

How Much Does a Living Trust Cost in San Diego?

Many clients ask about pricing before getting started.

The cost of a living trust depends on complexity, but for many middle-class families in San Diego, a typical estate planning package may cost significantly less than the long-term cost of probate or capital gains mistakes.

Working with a living trust attorney in San Diego can help ensure your trust is legally valid and customized to your goals. Our fee schedule is transparent and clearly published here:

Flat Fees for Estate Planning Services – San Diego

Frequently Asked Questions (FAQ)

What is a cost basis step up?

A cost basis step-up is a tax rule that allows an inherited asset’s cost basis to increase to its fair market value at the owner’s date of death.

How do you get a step-up in basis?

A step-up usually occurs when assets are inherited after someone dies, often through a trust or probate process.

Does a living trust provide a step-up in basis?

In many cases, yes. Assets in a revocable living trust may still qualify for a step-up in basis because they remain part of the person’s taxable estate.

Does step-up in basis apply to stocks?

Yes, stocks and brokerage accounts are common assets that may receive a step-up in basis when inherited.

Does step-up in basis apply to rental property?

In many cases, yes. Rental properties may receive a step-up in basis at death, which can reduce capital gains taxes for heirs.

Is it better to gift a house or leave it in a trust?

For many families, leaving the home in a trust is better because gifting during life may eliminate the step-up in basis and create major tax consequences.

Speak With a Living Trust Attorney in San Diego

Understanding the cost basis step up is one of the most important parts of protecting your family’s financial future.

Before gifting a home, transferring rental property, or adding children to title, it is critical to understand how the step-up in basis works and how it impacts your estate plan.

At San Diego Trust Lawyer, we help families create customized living trusts designed to protect their assets and preserve tax advantages whenever possible.

If you live in San Diego or Carmel Valley and want to create a plan that protects your family, contact our office to schedule a consultation.

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