Keogh Plan: When It Makes Sense (and When It Doesn't) vs. SEP or Solo 401(k)

If you've been reading about retirement plans for self-employed people and come across references to "Keogh plans," you've encountered a term that used to be important and is now mostly a historical artifact. Keogh plans still exist. They still appear in IRS publications. But in almost every situation where a self-employed person might once have considered a Keogh, the Solo 401(k) or SEP IRA has replaced it.

This deep dive covers what a Keogh plan actually is, why it was significant, why it's largely obsolete, and the narrow circumstances where the term still matters.

The Keogh plan is named for Eugene Keogh, a New York congressman who championed the Self-Employed Individuals Tax Retirement Act of 1962. Before 1962, self-employed people had essentially no tax-deferred retirement plan options. Corporate employees had pension plans. Self-employed people had only personal IRAs (introduced later in 1974). The Keogh Act changed this by allowing self-employed people to establish retirement plans with tax treatment comparable to corporate plans.

For several decades after 1962, the Keogh plan was the main tax-deferred retirement vehicle for sole proprietors, partners, and other self-employed people. The rules evolved through various legislative changes, but Keogh plans retained a distinct regulatory identity.

Then came the equalization. A series of tax law changes, culminating largely in the Economic Growth and Tax Relief Reconciliation Act of 2001 (EGTRRA) and subsequent legislation, eliminated most of the distinctions between Keogh plans and regular qualified retirement plans. By 2002-2003, the term "Keogh plan" had lost most of its technical meaning. What had been uniquely Keogh-specific rules now applied broadly to qualified plans.

Today, "Keogh plan" is effectively a synonym for "qualified retirement plan established by a self-employed person." It can refer to a money purchase pension plan, a profit-sharing plan, a defined benefit plan, or various other structures — but each of these has a more specific modern name. The term "Keogh" has largely fallen out of professional usage, except in IRS publications and older textbooks.

When someone today refers to a Keogh plan, they generally mean one of the following:

A profit-sharing plan. Annual employer contributions at employer discretion, up to 25% of compensation (or approximately 20% of net self-employment earnings). Contributions can be skipped in any given year. Similar in most respects to the profit-sharing side of a Solo 401(k), without the employee elective deferral option.

A money purchase pension plan. Required annual employer contributions at a fixed percentage of compensation specified in the plan document. Less common today because the mandatory contribution requirement is inflexible compared to profit-sharing plans, which offer the same contribution limit with discretionary annual funding.

A combined profit-sharing and money purchase plan. Historically, this combination was used to reach higher contribution limits. Current law allows the same total contribution through a profit-sharing plan alone, rendering the combination obsolete.

A defined benefit plan. A plan that promises a specific retirement benefit funded through actuarially determined annual contributions. Defined benefit plans are covered in 3.4 — they're a genuinely useful tool for high-income older owners, but they're rarely called "Keogh plans" in modern practice.

Any qualified retirement plan established by a self-employed person. A broad colloquial use that encompasses all of the above plus Solo 401(k) plans.

The practical point: "Keogh plan" doesn't typically refer to a distinct plan type you can establish today. It refers to an ecosystem of plans, most of which have been superseded in practice by Solo 401(k) plans or SEP IRAs.

For self-employed people, the Solo 401(k) beats a traditional profit-sharing-only Keogh plan in nearly every dimension:

Contribution capacity. Solo 401(k) allows employee elective deferrals on top of profit-sharing contributions. A profit-sharing Keogh alone tops out at 20-25% of compensation; a Solo 401(k) can add $23,000+ in elective deferrals on top.

Catch-up contributions. Solo 401(k) allows catch-up contributions at age 50+; most profit-sharing Keogh structures don't.

Roth option. Solo 401(k) can accept Roth elective deferrals; traditional Keogh plans generally can't.

Loan provisions. Solo 401(k) can allow participant loans; Keogh plans historically could too, but the Solo 401(k) ecosystem has more robust vendor support for loan administration.

Plan document support. The Solo 401(k) market has mature, competitively-priced prototype plan documents from major vendors. The traditional Keogh plan document market is thinner.

The one dimension where a traditional profit-sharing plan (sometimes called a Keogh) matters: if you're not making employee elective deferrals and you want maximum administrative simplicity, a profit-sharing plan can be marginally simpler than a full Solo 401(k) with a plan document supporting all the Solo 401(k) features. But even this comparison usually tips in favor of the Solo 401(k) once you consider that the profit-sharing plan gives up future flexibility.

If administrative simplicity is the priority, the SEP IRA beats the traditional Keogh plan:

No plan document. SEP IRA is established with Form 5305-SEP. Keogh plans require more substantial plan documents.

No annual filing. SEP IRA has no Form 5500 filing requirement. Keogh plans require Form 5500-EZ once assets exceed $250,000 (same as Solo 401(k)).

Same contribution limit. For a solo owner, the SEP IRA and a profit-sharing Keogh have essentially the same contribution limit (25% of compensation or 20% of net SE earnings).

Establishment flexibility. SEP IRAs can be established and funded up to the tax filing deadline. Keogh plans typically need to be established by the end of the tax year.

If the only retirement plan feature you want is the employer profit-sharing contribution (no elective deferrals, no catch-ups, no Roth), the SEP IRA delivers it with less administrative overhead than a traditional Keogh plan.

One modern use case where the "Keogh" terminology still appears with some regularity: defined benefit plans for self-employed individuals. High-income older self-employed people sometimes establish defined benefit plans — sometimes called defined benefit Keogh plans — to shelter much larger amounts annually than any defined contribution plan allows.

Defined benefit plans are covered in detail in 3.4. The short version: if you're 50+ and high-income, defined benefit plans can allow annual contributions of $100,000-$300,000+ in ways no defined contribution plan can match. The actuarial complexity is significant, and the annual administrative cost is higher ($2,000-$5,000+ for actuarial and compliance work). But for the right owner, the tax savings dwarf the administrative cost.

When a defined benefit plan for a sole proprietor is called a "Keogh plan," it's really just a defined benefit plan established by a self-employed person. The term is colloquial rather than technically distinct.

A few narrow historical or technical artifacts around Keogh plans that sometimes matter:

Existing Keogh plans established decades ago. If you have an active Keogh plan from before the 2002 equalization, it may still be operating under legacy rules. These plans typically have been updated through amendments to match current law, but the structure matters for ongoing administration. Owners of long-running plans should review the plan document with a qualified plan consultant periodically to ensure it reflects current law.

Plan termination. Terminating a Keogh plan has specific procedural requirements. Most business owners who want to replace a legacy Keogh with a modern Solo 401(k) or SEP IRA should coordinate the termination and replacement carefully to avoid prohibited transactions or compliance issues.

Rollover treatment. Keogh plan balances are generally rollover-eligible to IRAs and other qualified plans under the same rules that apply to other qualified plans. A Keogh balance can be rolled into a Solo 401(k) or IRA when the Keogh is terminated.

Nomenclature in IRS publications. The IRS still uses "Keogh plan" in some publications and instructions, typically as a reference to qualified plans established by self-employed people. If you see the term in instructions for Form 5500, Schedule K-1, or tax publications, it generally refers to any self-employed person's qualified plan.

The practical answer: almost never use that specific terminology. If you're establishing a retirement plan as a self-employed person today, you should be evaluating:

• Solo 401(k) if you want maximum flexibility and contribution capacity.
• SEP IRA if you want maximum simplicity.
• SIMPLE IRA if you have employees and want modest administrative overhead (covered in 3.5).
• Defined benefit plan if you're older, high-income, and want to shelter large amounts (covered in 3.4).
• Combination plans (Solo 401(k) + defined benefit) for high-income older owners wanting to maximize total contributions.

None of these are called "Keogh plans" in modern practice. If a broker, advisor, or plan administrator offers you a "Keogh plan" today, ask what specific plan type they're proposing. In almost every case, there's a modern alternative that's at least as good and usually better.

If you encounter the term "Keogh plan" in retirement planning reading, don't let it confuse you. The substance is just a qualified retirement plan established by a self-employed person. The specific features (contribution limits, rules, filing requirements) match whatever plan type the Keogh represents in that context — typically profit-sharing or defined benefit.

For planning purposes, work with the modern terminology: Solo 401(k), SEP IRA, SIMPLE IRA, or defined benefit plan. These are the plans you'll actually encounter when shopping for providers, reading plan documents, and managing your retirement strategy. "Keogh plan" is a historical name for a broader category that no longer maps cleanly to specific modern plan products.

The one time to care about Keogh-specific terminology: if you have an existing Keogh plan from years or decades ago. In that case, a review with a qualified plan consultant makes sense — both to ensure the plan is compliant with current law and to evaluate whether replacing it with a modern Solo 401(k) or SEP IRA would serve you better. For most owners with legacy Keogh plans, replacement is the right move.