The difference between a trustee and a co-trustee comes down to how authority is held. A sole trustee holds all of it and acts alone. Co-trustees share it and generally must act together, which changes how decisions get made, who’s liable when something goes wrong, and what happens when a trustee leaves or disagreements set in.
Both roles carry the same fiduciary duties: loyalty to the beneficiaries, prudent management of assets, impartiality, and following the trust document. The split is structural, not about what the job requires.
Authority and Day-to-Day Control
A sole trustee is the single person or institution responsible for everything the trust requires. That covers investing assets, distributing funds, paying bills, keeping records, and filing the trust’s annual income tax return. The sole trustee doesn’t need anyone’s permission to sell an investment, write a distribution check, or hire an accountant. Decisions happen quickly, and administration stays efficient.
Co-trustees are two or more people or institutions managing the trust together. Each has a right to participate in administration and an obligation to stay engaged with what the trust is doing. Grantors often appoint co-trustees to blend strengths. A frequent pairing puts a family member who understands the grantor’s values alongside a corporate trustee, like a bank or trust company, that brings professional investment management and administrative infrastructure. The family member keeps the human element in distribution decisions while the institutional trustee handles portfolio management, tax compliance, and recordkeeping.
The tradeoff is speed. A sole trustee decides and acts. Co-trustees must agree before they can do anything, and that requirement reshapes everything about how the trust operates.
How Co-Trustees Reach Agreement
The trust document sets the rules for how co-trustees act. It can require unanimous consent, meaning every co-trustee must approve before anything happens. Or it can allow majority rule, where most co-trustees can outvote the rest. In states that have adopted the Uniform Trust Code, which covers roughly 35 states and the District of Columbia, the default rule when the trust document is silent is that co-trustees who cannot reach a unanimous decision may act by majority.
Unanimous Consent
When a trust requires unanimity, a single dissenting co-trustee can block any action. If three co-trustees are managing a trust and one opposes selling a piece of real estate, the sale cannot happen. That’s a strong safeguard against rash decisions, but it creates real deadlock risk. When co-trustees fundamentally disagree about investment strategy, distribution timing, or whether to sell property, the trust can grind to a halt. Deadlock doesn’t just delay decisions. It can actively harm beneficiaries who need distributions.
Majority Rule
Under majority rule, two out of three co-trustees can approve an action over the third’s objection. This prevents any single trustee from holding the trust hostage, and it’s why many estate planning attorneys recommend it for trusts with three or more co-trustees. The dissenting co-trustee still has the right to participate in deliberations and to be heard. They can also document their objection, which matters for liability purposes if the decision later turns out to be a mistake.
When Co-Trustees Deadlock
Even under majority rule, two co-trustees can deadlock. When the trust document doesn’t include a tiebreaker, the co-trustees may need to petition a court for instructions, which is expensive and slow. Experienced estate planners often build in safeguards: giving one co-trustee the deciding vote on specific categories of decisions, naming a trust protector who can break ties, or including a mandatory mediation clause. These provisions cost nothing to add during drafting and can save tens of thousands in legal fees later.
Dividing the Work
Acting together on every decision isn’t always practical. Under the Uniform Trust Code, a co-trustee can delegate specific administrative functions to another co-trustee as long as the trust document doesn’t prohibit it, and the delegation must be in writing. A family member co-trustee might delegate investment decisions to the corporate co-trustee while retaining authority over distribution requests.
Delegation has limits. A co-trustee cannot delegate a function the grantor reasonably expected the trustees to perform jointly. If the trust was clearly designed so that both a family member and a professional would weigh in on large distributions, one of them can’t simply hand that responsibility to the other. Delegation also doesn’t erase the delegating trustee’s responsibility. A co-trustee who delegates must still monitor what the other trustee is doing, and unless the delegation was irrevocable, the delegating co-trustee can take the function back at any time.
Co-trustees can also delegate certain functions to outside professionals, such as hiring an investment advisor to manage the trust’s portfolio. The trustee must use reasonable care in selecting the advisor, defining the scope of the delegation, and periodically reviewing performance. A trustee who follows those steps is generally not liable for the advisor’s decisions. A sole trustee has the same ability to hire outside professionals but no co-trustee to delegate to internally.
Liability When Something Goes Wrong
A sole trustee bears complete personal liability for any breach of fiduciary duty. A negligent investment that loses money, an improper distribution, a missed tax filing: the sole trustee is personally on the hook to make the trust whole.
Co-trustee liability is more complicated and, in some ways, more dangerous. The general rule is joint and several liability, meaning each co-trustee can be held responsible for the full amount of any loss, not just a proportional share. A beneficiary who suffers a $300,000 loss due to mismanagement can sue any one co-trustee for the entire amount. That co-trustee’s recourse is to seek contribution from the others afterward, which offers cold comfort if the other co-trustees lack the assets to pay.
The Duty to Watch Your Fellow Trustees
Co-trustees can’t stay in their own lane and ignore what the other trustees are doing. Each co-trustee has an affirmative duty to monitor the others and take reasonable steps to prevent or remedy a breach of trust. A co-trustee who looks the other way while another co-trustee makes self-dealing investments is liable, not for committing the breach, but for failing to stop it. The same applies to a co-trustee who delegates administration to a fellow trustee without checking in.
This is where co-trusteeship gets uncomfortable. Passive negligence, like never reviewing account statements or skipping trustee meetings, can create personal liability just as surely as active wrongdoing. Even resigning won’t necessarily cut off liability if the resignation was designed to clear the way for a breach the resigning trustee knew or should have known was coming. A sole trustee has no monitoring duty of this kind, simply because there’s no one else to monitor.
Compensation
Trustees are entitled to be paid for their work. When the trust document specifies compensation, that amount controls, though a court can adjust it if the trustee’s actual duties turn out to be significantly different from what the grantor anticipated, or if the specified amount is unreasonably high or low.
When the trust document is silent, the trustee is entitled to “reasonable compensation.” Factors include the complexity of the trust assets, the time commitment, the trustee’s skill and expertise, the results achieved, and what professional trustees in the community typically charge. Corporate trustees commonly charge an annual fee based on a percentage of trust assets, often in the range of 0.5% to 1.5% depending on size and complexity.
Compensation works differently for co-trustees in a way worth understanding before accepting the role. The total paid to all trustees combined is based on the total services provided, not multiplied by the number of trustees. Two co-trustees managing a trust don’t each get a full trustee fee; they split compensation that reflects the overall work performed. If outside professionals like investment advisors handle functions that would otherwise fall to the trustees, their fees are taken into account when setting what the trustees themselves should be paid. Trustees in either structure can be reimbursed for legitimate out-of-pocket expenses, such as insurance premiums, property repairs, or professional fees.
What Happens When a Trustee Leaves
Trusteeships don’t always last as long as the trust does. Trustees resign, become incapacitated, die, or get removed. How the trust absorbs that change is one of the practical differences between the two structures.
Under the Uniform Trust Code model, a trustee can resign without court approval by giving at least 30 days’ written notice to the grantor (if living), all qualified beneficiaries, and any co-trustees. The trust document can modify this process. Resigning doesn’t automatically discharge a trustee from liability for actions or inactions during their service.
Courts can remove a trustee for several reasons, including a serious breach of trust, unfitness or persistent failure to manage the trust effectively, or a substantial change in circumstances where all qualified beneficiaries request removal. One ground applies specifically to co-trustees: lack of cooperation among them that substantially impairs administration. That recognizes that personality conflicts or philosophical disagreements between co-trustees can make a trust unmanageable even when no one has technically done anything wrong.
When a vacancy occurs in a co-trusteeship, the remaining co-trustees can continue to act for the trust without filling the vacancy. If one co-trustee is temporarily unavailable due to illness, travel, or other incapacity and action is urgently needed, the remaining co-trustees can act without the absent trustee to protect the trust. If all co-trustees are gone, the vacancy must be filled, typically by a successor named in the trust document, by agreement of the beneficiaries, or by court appointment. A sole trusteeship has no such backup. If the sole trustee becomes incapacitated, someone must petition a court or invoke a successor trustee provision before anything can happen.
Which Structure Fits Your Trust
Neither structure is inherently better. The right choice depends on the trust’s complexity, the people available to serve, and the grantor’s priorities.
A sole trustee tends to fit when the trust is straightforward, a highly competent and trustworthy individual or institution is available, speed of decision-making matters, and the grantor doesn’t want the overhead of coordinating multiple trustees.
Co-trustees tend to fit when the trust involves complex assets that benefit from both personal knowledge and professional management, when the grantor wants built-in checks and balances, when no single person has all the skills needed, or when the grantor wants a family member involved but doesn’t fully trust them to act alone.
The most common mistake grantors make is appointing co-trustees who can’t work together. Naming two siblings who don’t get along as co-trustees of a parent’s trust is a recipe for deadlock, court petitions, and legal fees that drain the very assets the trust was created to protect. If the grantor insists on multiple trustees, the trust document should include clear decision-making rules, a deadlock-breaking mechanism, and defined areas of responsibility for each co-trustee. Those safeguards won’t eliminate conflict, but they give the co-trustees a framework for resolving it without a judge.