The Hidden Disaster of Naming Co-Trustees in California (And Why It So Often Goes Wrong)

Quick Answer: Should You Name Co-Trustees in California?

No, in most cases. Co-trustees create more problems than they solve. Under California Probate Code §15620, co-trustees must act unanimously on all decisions, creating bottlenecks, conflicts, and shared liability that often leads to lawsuits and family disputes.

Better alternatives:

• Name a single capable trustee with clear successor trustees
• Use a professional trustee or trust company
• Give advisory roles instead of co-trustee authority

What Is a Co-Trustee in California?

A co-trustee is one of two or more individuals appointed to manage a trust together. Under California law, unless the trust document states otherwise, all co-trustees must agree on every decision (California Probate Code §15620).

Example: If you name your two adult children as co-trustees of your living trust, both must agree before they can:

• Sell your house
• Make investment decisions
• Distribute money to beneficiaries
• Pay bills from the trust
• Hire professionals

Co-Trustees vs. Single Trustee: California Comparison Table

On paper, naming co-trustees sounds like a great idea.

Two heads are better than one. Built-in accountability. Shared responsibility. Maybe even a little family harmony.

It feels fair.

It feels safe.

It feels like you’re preventing problems.

But in reality, naming co-trustees is one of the most common ways California families create conflict, delay, and outright legal disaster inside a trust.

After handling hundreds of trust administration cases in Sacramento and throughout Northern California, I can tell you: if you want to design a system that guarantees friction, slows down decisions, and increases the risk of lawsuits, co-trustees are a very effective way to do it.

Let me walk you through why.

The Big Problem Nobody Sees Coming: Everything Requires Agreement

Here’s the rule that quietly causes most of the trouble.

Under California Probate Code §15620, unless the trust says otherwise, co-trustees must act unanimously.

That means:

• Selling a house
• Making an investment
• Distributing money to beneficiaries
• Hiring attorneys or accountants
• Signing tax returns

All of it requires agreement. Every single decision.

Now think about real life.

You’re asking two human beings-often family members with different personalities, priorities, and financial instincts-to agree on every meaningful decision.

That’s not a system. That’s a bottleneck.

And when they don’t agree, the trust doesn’t move.

What Happens When Sacramento Co-Trustees Disagree? Nothing… Or Something Worse

When co-trustees disagree, one of two things happens.

First option: Nothing happens.

The trust freezes. Decisions get delayed. Bills go unpaid. Assets sit idle. Opportunities are lost.

I’ve seen Sacramento families lose real estate deals because co-trustees couldn’t agree on pricing. I’ve seen investment portfolios stagnate because siblings couldn’t agree on strategy.

Second option: Someone acts anyway.

And now you have a different problem.

Because if one co-trustee takes action that the other believes is improper, that disagreement can escalate into a legal dispute.

At that point, the solution isn’t a conversation.

It’s a court petition in Sacramento County Superior Court.

California Probate Code §17200 specifically allows a co-trustee to petition the court to resolve disputes or stop another trustee’s actions.

So instead of smooth administration, you get:

• Deadlock
• Delay
• Legal fees ($15,000+ easily)
• Family tension
• And in some cases, a full-blown lawsuit

It Gets Worse: You Can Be Liable for What the Other Trustee Does

Here’s where things become dangerous.

Most people assume that if there are two trustees, responsibility is split 50/50.

That’s not how California law sees it.

Under California Probate Code §16004, a co-trustee can be liable for another trustee’s mistake if they:

• Participate in it
• Approve it
• Ignore it
• Fail to stop it

Let that sink in.

You can be held personally responsible for something you didn’t even do.

If your co-trustee makes a bad investment and you did nothing to stop it, you may still be on the hook.

If you knew something was wrong and didn’t act, that alone can create liability under California’s trust law.

In fact, the rules are so broad that it’s difficult to imagine a situation where a co-trustee escapes responsibility entirely.

So now you have:

• Shared decision-making
• Shared risk
• Shared liability

That’s not a partnership. That’s mutual exposure.

The Myth of “Division of Duties”

Some Sacramento estate planning attorneys try to solve the co-trustee problem by dividing responsibilities in the trust document.

“One handles investments. The other handles distributions.”

Or: “One is the ‘money person’ and the other is the ‘family person.’”

Sounds logical.

But it doesn’t eliminate the problem.

Even when powers are divided under California Probate Code §16012, each trustee still has fiduciary duties and oversight responsibilities.

That means:

• You can’t completely ignore what the other trustee is doing
• You can’t blindly rely on their decisions
• You can’t delegate everything and walk away

If something goes wrong, “that wasn’t my job” is not a defense under California trust law.

You’re still expected to supervise.

So now you have the worst of both worlds:

• Divided responsibilities
• Shared liability

The Delegation Trap in California Trust Administration

Here’s another issue that catches Sacramento families off guard.

Under California Probate Code §16012, co-trustees are not allowed to simply hand off responsibilities to each other.

With limited exceptions, trustees cannot delegate core fiduciary duties.

So even if one trustee is a Sacramento financial advisor and the other knows nothing about investing, the inexperienced trustee can’t just say: “You handle it.”

That can itself be a breach of fiduciary duty.

Now imagine this in a real California family:

• One sibling is financially savvy
• The other is not

The less experienced trustee either:

1. Gets deeply involved in decisions they don’t understand, or

2. Steps back and risks liability for not participating

Neither outcome is good.

The Documentation Nightmare

When you have co-trustees administering a California trust, everything needs to be documented.

Every decision.

Every discussion.

Every disagreement.

The safest practice under California law is for each trustee to approve or reject actions in writing, explaining their reasoning.

Why?

Because you have to assume that someday, a beneficiary will challenge what you did in Sacramento County probate court.

Now imagine the administrative burden:

• Emails
• Letters
• Written confirmations
• Records of conversations
• Formal trustee meeting minutes

This isn’t casual.

This is a paper trail designed for court.

When California Co-Trustees Don’t Get Along (Which Is Often)

Let’s talk about the real issue.

People.

In my Sacramento practice, co-trustees are often:

• Siblings
• Blended family members
• A child and a surviving spouse
• A professional trustee and a family member

These relationships are rarely neutral.

And when conflict arises, it doesn’t stay small.

California law even recognizes this.

In Estate of Gilmaker (2019), the California Court of Appeal held that hostility between co-trustees that interferes with administration can justify removing a trustee under Probate Code §15642.

Think about that.

The structure itself can fail simply because the people can’t work together.

Deadlock Is Not Rare in Sacramento Trusts. It’s Expected.

When you require unanimous decisions under California law, disagreement isn’t an exception.

It’s the default risk.

And when co-trustees regularly disagree, California law offers three main solutions:

1. One trustee resigns (Probate Code §15640)

2. One trustee is removed by court order (Probate Code §15642)

3. A third trustee is appointed to break ties

None of these are good outcomes.

They all involve:

• Legal fees
• Sacramento County court involvement
• Delay
• Family stress

So the system you thought would create stability actually creates instability.

The “Unavailable Trustee” Problem

Life happens.

One trustee is traveling. Sick. Busy. Unresponsive.

Now what?

California Probate Code §15620(c) allows one trustee to act in emergencies if necessary to prevent harm to the trust.

But this isn’t a clean solution.

Because now you have to justify:

• Why action was necessary
• Why the other trustee was unavailable
• Why the decision couldn’t wait

And yes, that should all be documented.

Again, more complexity. More risk.

Investment Decisions: Where California Co-Trustees Really Break Down

If there’s one area where Sacramento co-trustees struggle the most, it’s investments.

Different risk tolerance.

Different investment philosophies.

Different opinions about timing.

Under California’s Prudent Investor Rule (Probate Code §§16045-16054), trustees must invest prudently.

But when you have two trustees with different investment strategies, you get:

• Missed opportunities
• Overly conservative decisions (missing market gains)
• Or reckless compromises (to avoid conflict)

Even worse, one trustee may try to dominate the process, effectively taking control.

That can create improper delegation issues and additional liability for both trustees.

The Illusion of Control

Many Sacramento families name co-trustees because they want control.

They think:

“If I put two people in charge, they’ll keep each other in check.”

But what actually happens in California trust administration is this:

• Decisions slow down
• Responsibility becomes blurred
• Accountability weakens
• Conflict increases

Instead of control, you get friction.

Instead of protection, you get exposure.

Real California Example: Everyone Gets Sued

There’s a case referenced in California trust administration materials where three co-trustees made a bad investment.

The investment failed.

And all three trustees were held liable under California Probate Code §16004.

Not just the one who pushed for the investment.

All of them.

Why?

Because they were all involved. All responsible. All expected to act under California’s fiduciary duty standards.

That’s the reality of co-trustees in California.

Shared control means shared consequences.

Even Resigning Doesn’t Save You in California

Here’s a surprising twist under California trust law.

If you think something is wrong and you resign instead of dealing with it, that can still be a problem.

Under Probate Code §16004, if your resignation allows wrongdoing to continue, it can itself be considered a breach of fiduciary duty.

So you can’t:

• Ignore problems
• Walk away from problems
• Avoid responsibility by resigning

Once you’re a California trustee, you’re in.

Why Sacramento Families Still Choose Co-Trustees

Despite all of this, Sacramento families still choose co-trustees.

Why?

Usually for emotional reasons:

• ”I don’t want to pick one child over another”
• ”They’ll work it out”
• ”It keeps things fair”

But fairness in theory doesn’t translate to effectiveness in practice under California law.

In fact, it often creates the opposite.

A Better Approach for Sacramento Families

If the goal is to protect your family and avoid conflict, there are better options under California law:

1. Name a single, capable trustee

Give one person clear authority. Name successors if they can’t serve.

2. Use a professional trustee when appropriate

Sacramento has excellent professional trustees and trust companies who do this for a living.

3. Give limited roles to others instead of full authority

You can name a “trust protector” or “distribution advisor” without making them a co-trustee.

4. Use clear distribution standards

The clearer your trust instructions, the less room for disagreement.

You can still involve multiple people.

You just don’t need to give them equal authority over everything.

Frequently Asked Questions: Co-Trustees in California

Q: Can co-trustees split responsibilities in California?

A: Technically yes, under California Probate Code §16012, but it doesn’t eliminate liability. Each trustee is still responsible for supervising the other trustee’s actions. If you divided duties and the other trustee makes a mistake, you can still be held liable for failing to oversee their actions.

Q: What happens if co-trustees can’t agree in California?

A: The trust freezes until they resolve the disagreement or seek court intervention under Probate Code §17200. This can cost $15,000+ in legal fees and cause significant delays in trust administration.

Q: Can one co-trustee act alone in an emergency?

A: Under California Probate Code §15620(c), yes-but only if action is necessary to prevent harm to the trust and the other trustee is unavailable. This must be documented and justified.

Q: Are both co-trustees liable if one makes a mistake?

A: Yes. Under California Probate Code §16004, a co-trustee can be held liable for another trustee’s breach if they participated in it, approved it, ignored it, or failed to take reasonable steps to prevent it.

Q: How do you remove a co-trustee in California?

A: Either the co-trustee resigns voluntarily (Probate Code §15640), or you petition the court for removal under Probate Code §15642. Grounds include breach of trust, hostility that interferes with administration, or unfitness.

Q: Is naming co-trustees ever a good idea in California?

A: Rarely. The only situation where it might work is when:

• Both trustees are professional fiduciaries (not family)
• The trust document clearly defines decision-making authority
• There’s a tie-breaking mechanism built in
• The trustees have an established working relationship

Even then, a single professional trustee is usually more efficient.

Q: Can a California trust have 3 co-trustees?

A: Yes, but it makes the problems worse. Three co-trustees typically require unanimous decisions or majority approval (if the trust specifies). More trustees = more complexity, more potential for conflict.

Q: What’s better than naming co-trustees?

A: Name a single trustee with clear successor trustees. You can also give others advisory roles (trust protector, distribution committee) without making them co-trustees with full fiduciary liability.

Final Thought: Simple Is Strong. Complex Breaks.

California trusts work best when they’re simple.

Clear authority.

Clear responsibility.

Clear accountability.

Co-trustees introduce complexity at every level:

• Decision-making
• Communication
• Liability
• Family relationships

And complexity is where things break.

If you’re designing a California living trust, the question isn’t:

“Does this feel fair?”

The real question is:

“Will this actually work when emotions, money, and family collide?”

Because that’s when the structure is tested.

And that’s when co-trustees often fail.

About the Author

Dustin MacFarlane is a California State Bar Certified Specialist in Estate Planning, Trust & Probate Law (State Bar #262162) and founder of California Probate and Trust, PC. He has been helping Sacramento and Northern California families with estate planning since 2009.

California State Bar certification as a Certified Specialist requires passing a rigorous examination, substantial specialized experience, continuing education, and peer review recognition. Fewer than 10% of California attorneys hold this credential.

Dustin does not handle litigation-his practice focuses exclusively on estate planning, trust administration, and helping families avoid probate while minimizing taxes and preserving wealth for future generations.

California Probate and Trust, PC
6957 Douglas Blvd., Granite Bay, CA 95746
Phone: (866) 400-0058
Email: dustin@cpt.law
State Bar #262162 | Certified Specialist: Estate Planning, Trust & Probate Law

This article reflects California law as of March 2026. It is provided for general information only and does not constitute legal advice. Every situation is unique; consult with a qualified California estate planning attorney about your specific circumstances.

About the Author: Dustin MacFarlane, Esq.

California Licensed Attorney | Estate Planning Specialist

Dustin MacFarlane is the founder of California Probate and Trust, PC, with over 15 years of experience in estate planning, probate administration, and trust law. Licensed by the California State Bar, Dustin has helped thousands of California families protect their assets and plan for the future.

CA Bar License: Active | Practice Areas: Estate Planning, Probate, Trust Administration | Location: Granite Bay, CA