A commingled trust fund is a pooled investment vehicle that a bank or trust company creates by blending assets from multiple fiduciary accounts, most often employer retirement plans, into a single portfolio it manages as trustee. Pension plans, profit-sharing plans, and other institutional trust accounts buy units of the pool, gaining the diversification and pricing power of a much larger investor. The vehicle looks a lot like a mutual fund from the outside, but it lives under banking regulation rather than securities regulation, and that single fact drives almost every practical difference.
What a Commingled Trust Fund Actually Is
A CTF is a trust, not a corporation. A bank creates it by drafting a foundational document called a Declaration of Trust, sometimes just called the Plan. That document spells out the investment strategy, the fee structure, the rules for joining and leaving, and how the bank will value the assets. Every operational detail flows from it.
The commingling itself is straightforward. The bank takes money from separate fiduciary accounts it already manages and blends those assets into one large portfolio. Pooling lets the bank buy larger blocks of securities, negotiate better pricing, and access strategies that require high minimums. A corporate pension with $5 million in assets couldn’t touch many institutional strategies on its own. Combined with dozens of similar accounts in a CTF, it can.
The legal structure matters because it determines who regulates the fund and who can invest in it. A national bank maintaining a CTF answers to the Office of the Comptroller of the Currency, whose rules at 12 CFR Part 9 govern collective investment funds.1Legal Information Institute. 12 CFR Part 9 – Fiduciary Activities of National Banks State-chartered banks answer to their state banking regulators under parallel fiduciary standards. Federal securities laws carve CTFs out of registration requirements as long as the fund stays within its lane: it must serve as an aid to the bank’s fiduciary administration, interests can’t be advertised or offered to the public, and fees must be consistent with fiduciary principles.
How It Compares to a Mutual Fund
The comparison is inevitable because both vehicles pool investor money into a diversified portfolio. The similarities are mostly surface-level. Mutual funds are typically structured as corporations or trusts registered with the SEC under the Investment Company Act of 1940, and they’re available to anyone with a brokerage account.2Securities and Exchange Commission. Investment Company Registration and Regulation Package CTFs are trusts maintained by banks and restricted to institutional fiduciary accounts.
That regulatory gap produces differences you’ll feel as a plan sponsor or trustee. CTFs don’t issue a prospectus. They don’t publicly disclose their holdings on a set schedule the way mutual funds must. They tend to be significantly cheaper, because skipping SEC registration and retail marketing lowers operating costs, and those savings typically pass through as lower management fees.
The trade-off is transparency and portability. If your plan uses a CTF and you switch to a recordkeeper whose bank doesn’t offer the same fund, you may need to liquidate the position entirely. Mutual fund shares can generally follow you from one custodian to another. CTFs also lack the independent board of directors that the Investment Company Act requires for mutual funds; governance sits with the bank’s own trust committee.
Who Can Invest
You can’t walk into a bank and buy units of a CTF the way you’d buy mutual fund shares. Participation is limited to accounts for which the bank already serves in a fiduciary capacity. Under OCC regulations, a national bank can maintain two main types of collective investment funds.3eCFR. 12 CFR 9.18 – Collective Investment Funds
- Funds for fiduciary accounts, holding money the bank manages as trustee, executor, administrator, guardian, or custodian under a uniform gifts to minors act.
- Funds restricted to tax-exempt retirement assets, holding only money from pension, profit-sharing, stock bonus, or other trusts exempt from federal income tax. Here the bank can serve in any fiduciary capacity, including as agent, as long as the fund itself qualifies for tax exemption.
In practice, the largest users are 401(k) plans, defined benefit pensions, profit-sharing plans, and certain governmental plans. The common thread is a pre-existing fiduciary relationship with the managing bank. Individual retail investors, IRAs in most cases, and accounts where the bank acts in a non-fiduciary role don’t qualify. The bank’s trust committee reviews each account seeking admission.
This restriction isn’t just policy preference. It’s the mechanism that preserves the fund’s exemption from securities registration. The moment a CTF opens its doors to the public, it looks like a mutual fund in the eyes of federal securities law and would have to register as one.
How Units, Pricing, and Withdrawals Work
CTFs use a system called unitization that works much like mutual fund shares. Total net assets are divided into units of participation, and each account owns a number of units proportional to its investment. A plan contributing $1 million buys units at the current price; a plan withdrawing money redeems units.
Each unit’s price is the fund’s net asset value per unit: total market value of assets minus liabilities, divided by outstanding units. OCC rules require banks to value readily marketable assets at least once every three months, and assets that aren’t readily marketable at least once a year.3eCFR. 12 CFR 9.18 – Collective Investment Funds Many equity and bond CTFs price daily, matching the cadence of mutual funds. Funds holding real estate or private investments may value only monthly or quarterly.
Every purchase or redemption must occur at the NAV determined on a valuation date, and the bank must approve the request on or before that valuation date. No changes are allowed after the cutoff. This prevents any single participant from timing its transactions to gain an advantage over others in the pool.
There’s no universal federal notice period for withdrawals. Each fund’s written Plan specifies its own admission and withdrawal terms. A CTF invested in publicly traded stocks might allow redemptions on any business day with a day or two of notice. A fund holding commercial real estate or private equity could require 30, 60, or 90 days’ notice, and may cap how much can be redeemed in any given period. The bank must make the Plan available for public inspection at its main office or on its website, and must provide a copy on request. If you’re evaluating a CTF for a retirement plan, that document is where the liquidity terms live.
Tax Treatment
A common trust fund is not subject to federal income tax and is not treated as a corporation for tax purposes. Income flows through to the participating accounts. Each participant includes its proportionate share of the fund’s short-term capital gains, long-term capital gains, and ordinary income when computing its own taxable income, whether or not the income was actually distributed.4Office of the Law Revision Counsel. 26 USC 584 – Common Trust Funds The fund’s taxable income is computed much like an individual’s, but the fund itself cannot claim deductions for charitable contributions or net operating losses.
For most participants, this pass-through is invisible. The bulk of CTF money sits inside tax-exempt retirement plans, so income flowing through isn’t taxed at the participant level either. The fund’s tax-exempt status simply prevents a layer of taxation that would otherwise eat into returns before they reach the plan. For non-retirement fiduciary accounts such as personal trusts or estates, the pass-through income does appear on the account’s own tax return.
Risks and Trade-Offs to Weigh
CTFs offer genuine cost and diversification advantages, but they come with trade-offs that plan sponsors and fiduciaries should weigh carefully.
- Limited transparency. CTFs aren’t required to file a prospectus or publicly disclose portfolio holdings on a regular schedule. You’ll get periodic reports from the bank, but the level of detail is governed by the Declaration of Trust and banking regulations, not the more prescriptive SEC disclosure rules that apply to mutual funds.
- No independent board. Mutual funds must have boards with independent members who oversee fund management. CTFs have no such requirement. The bank’s trust committee provides governance, without a structural check from outside directors representing participants’ interests.
- Portability constraints. If your plan changes recordkeepers or trust companies, you likely can’t transfer CTF units to the new provider. The investment exists only within the managing bank’s trust structure. Moving typically means liquidating and reinvesting elsewhere, which can trigger transaction costs and timing gaps.
- Variable liquidity. CTFs that invest in less liquid assets may restrict how often and how quickly participants can withdraw. The terms are in the Plan document, and they vary widely from fund to fund.
- No leverage or illiquidity caps. Banking regulations don’t impose the same limits on illiquid holdings or borrowing that the Investment Company Act places on mutual funds. A CTF can hold a larger share of hard-to-sell assets without triggering regulatory restrictions, which can become a problem in a downturn when multiple participants want out at once.
None of these limitations make CTFs inherently risky. They make due diligence more important. A plan fiduciary selecting a CTF should review the Declaration of Trust carefully, understand the valuation and redemption terms, compare the fee structure against comparable mutual fund options, and confirm the bank’s track record managing similar strategies. The cost savings are real, and so is the responsibility to understand what you’re buying into.