Best Retirement Plan for a Small Business Owner: Solo 401(k), SEP, SIMPLE, and Defined Benefit Compared

The best retirement plan for small business owner with no employees other than themselves (and possibly a spouse) is almost always the Solo 401(k). The plan allows both elective deferral and employer contribution components, which together can absorb $72,000 to $83,250 of annual contributions in 2026 depending on the owner’s age. The administration is minimal compared to a traditional 401(k) because there is only one participant (or two with a spouse), no non-discrimination testing applies, and Form 5500-SF only becomes required when plan assets exceed $250,000. The flexibility, the high contribution limits, and the low administrative burden make the Solo 401(k) the default choice for our typical S corporation client.

Comparing the Solo 401(k) to the SEP-IRA on identical compensation: an S corporation owner with $120,000 of W-2 wages can contribute $54,500 to a Solo 401(k) ($24,500 elective deferral plus $30,000 employer contribution) but only $30,000 to a SEP-IRA. The $24,500 differential is significant, and the elective deferral piece of the Solo 401(k) is what creates the advantage. The SEP has no employee elective deferral component; everything is employer contribution capped at 25 percent of compensation. For an owner who wants to make the most of retirement contributions, the Solo 401(k) wins on math every time at any compensation level.

The best retirement plan for small business owner with a spouse on payroll is still the Solo 401(k), now covering both spouses. Each spouse can contribute their own elective deferral up to $24,500 ($32,500 with catch-up) and receive their own employer contribution up to 25 percent of their compensation. For a couple with combined W-2 wages of $240,000 ($120,000 each), the combined Solo 401(k) contribution can reach $109,000 in 2026 ($49,000 elective deferral combined plus $60,000 employer contribution combined). The household tax savings on $109,000 of contributions at typical marginal rates exceeds $40,000 per year.

Roth elective deferrals to a Solo 401(k) are available and increasingly popular under SECURE 2.0. The Roth deferral is taxed in the contribution year but grows tax-free and is tax-free at withdrawal. For owners who expect to have substantial taxable account assets and want to diversify the tax character of their retirement portfolio, splitting the elective deferral between traditional and Roth is a reasonable approach. The employer contribution must be traditional (pre-tax), so the Roth option is limited to the $24,500 elective deferral piece. SECURE 2.0 also allowed Roth treatment of employer contributions under certain plan designs starting in 2023, but most plans have not adopted this feature yet.

The best retirement plan for small business owner who is over 50 gets a meaningful boost from the catch-up contribution. The $8,000 age-50 catch-up applies to the elective deferral, bringing the total elective deferral to $32,500. Combined with the $30,000 employer contribution on $120,000 of wages, the total Solo 401(k) contribution for a 55-year-old earning $120,000 is $62,500. SECURE 2.0 added a higher catch-up amount for ages 60-63 ($11,250 in 2026), which can push the contribution to $35,750 elective deferral plus the employer contribution for a 61-year-old.

Self-employed individuals (sole proprietors, single-member LLC owners not electing S status) have a slightly different Solo 401(k) calculation. The contribution is based on net earnings from self-employment minus one-half of self-employment tax minus the contribution itself (a circular calculation that the IRS Pub 560 worksheet handles). The effective employer contribution rate is roughly 20 percent of net SE earnings, not 25 percent. For a sole proprietor with $150,000 of net SE earnings, the combined Solo 401(k) contribution is roughly $53,500 to $54,500, similar to an S corp owner with $120,000 in wages. The math is different but the result is comparable.

The Solo 401(k) has a Form 5500-SF filing requirement once plan assets exceed $250,000 at year-end. Below the threshold, no annual filing is required, which keeps administration genuinely minimal. The Form 5500-SF is a simplified version of Form 5500 and takes 30 to 60 minutes to complete annually. Most plan custodians (Fidelity, Vanguard, Schwab, etc.) provide a year-end statement that has all the information needed for the filing. The cost of administering a Solo 401(k) beyond the basic custodial fee is essentially zero.

Loan provisions are available in many Solo 401(k) plan documents. The participant can borrow up to 50 percent of the vested balance or $50,000, whichever is less, with repayment within 5 years (or longer if the loan is for the purchase of a primary residence). The loan interest is paid back to the participant’s own account. This feature is useful as a backup liquidity source but is not the primary value of the Solo 401(k). The contribution and tax-deferral mechanics are the main benefit.

Our practice opens Solo 401(k) accounts for S corporation clients regularly and the recurring observation is that the plan over-delivers on contribution capacity for almost every small business owner. The best retirement plan for small business owner with a single-participant setup is the Solo 401(k), full stop. We typically recommend Vanguard, Fidelity, or Schwab as the custodian because their fees are minimal, their fund selection is broad, and their Solo 401(k) plan documents are well-tested. The setup takes 1 to 2 weeks once the entity is in place, contributions can be funded through ACH transfers directly from the corporate operating account, and the year-end paperwork is straightforward. The administrative simplicity combined with the maximum contribution limits makes the Solo 401(k) the right default for the vast majority of single-owner S corporations we work with.

One final note on the Solo 401(k) versus brokerage prototype plans. The major custodians offer a free prototype plan document that satisfies the IRS qualification requirements without any plan design fees. Custom plan documents (typically drafted by a third-party administrator) offer more features like in-service withdrawals, expanded loan provisions, after-tax contributions for mega-backdoor Roth conversions, or different vesting schedules. For most clients, the prototype is the right choice because the features they would add are not enough to justify the $500-$1,500 annual TPA fee. For owners specifically pursuing mega-backdoor Roth strategies (after-tax contributions converted to Roth within the plan), a custom document is required because most prototype documents do not allow after-tax contributions beyond the elective deferral limit. The decision turns on the specific strategies the owner wants to run inside the plan.

The best retirement plan for small business owner with 5 to 15 non-owner employees gets more complex because the plan must cover the employees under non-discrimination rules. The Solo 401(k) is no longer available; a corporation with non-owner employees needs a full 401(k) plan (or a SEP, SIMPLE, or defined benefit plan). The choice depends on what the owner wants to contribute for themselves, how much the owner is willing to contribute for employees, and the administrative complexity tolerance.

The full 401(k) plan (sometimes called a Safe Harbor 401(k) when set up to avoid annual non-discrimination testing) allows the owner to defer up to $24,500 and gives the corporation flexibility on employer contributions. The Safe Harbor 401(k) requires either a 3 percent non-elective contribution for all eligible employees or a 4 percent match (formally, 100 percent of the first 3 percent of compensation deferred plus 50 percent of the next 2 percent). The Safe Harbor design avoids the §401(k) ADP test and the §401(m) ACP test, which can prevent the owner from contributing the maximum if non-owner employees defer less.

The best retirement plan for small business owner trying to balance owner contributions with employee costs is often a Safe Harbor 401(k) plus profit sharing, with allocation formulas designed to favor the owner. A new comparability profit sharing allocation can allocate a much higher percentage of compensation to the owner than to employees if certain rules under §401(a)(4) are satisfied. For a corporation with the owner at $300,000 of compensation and 10 employees averaging $50,000, a well-designed new comparability plan can allocate 30 to 40 percent of the profit sharing to the owner and 5 to 7.5 percent to employees, dramatically increasing the owner’s contribution capacity while limiting employee costs.

Cash balance plans paired with a 401(k) are the more sophisticated approach for owners with employees who want to contribute very large amounts. The cash balance plan funds an owner benefit that can absorb $100,000 to $250,000+ per year, with corresponding (smaller) accruals for employees. The combined 401(k) plus cash balance structure can produce annual contributions of $200,000 to $350,000 for the owner, with $20,000 to $40,000 of employee contributions covering the workforce. The math works for owners earning $400,000+ in W-2 wages who want to make the most of tax-deferred contributions over a 10-15 year horizon to retirement.

The best retirement plan for small business owner with employees who want minimal administration is the SEP-IRA. The SEP must cover all employees who are at least 21 years old, have worked for the corporation in 3 of the last 5 years, and earned at least $750 in the current year. The contribution percentage must be the same for all eligible employees including the owner. So if the owner contributes 20 percent of compensation for themselves, the corporation must contribute 20 percent of compensation for every eligible employee. This makes the SEP expensive when there are non-owner employees, because the owner is essentially paying for the employees’ retirement contributions to access their own.

The SIMPLE IRA is another low-administration option but with lower contribution limits. The 2026 SIMPLE elective deferral limit is $16,500 ($20,000 with age-50 catch-up). The employer must match employee contributions up to 3 percent of compensation or make a non-elective 2 percent contribution. For an owner with $120,000 of wages and a workforce of 10 employees averaging $50,000, the SIMPLE costs the corporation $15,000 in employee matches (assuming all employees contribute enough to receive the full match) plus the owner’s own $16,500 contribution and $3,600 match. The total package is roughly $35,100 in contributions, of which the owner receives $20,100.

Comparing structures for a corporation with 10 non-owner employees and an owner earning $300,000 in W-2 wages: a Safe Harbor 401(k) with profit sharing can deliver $72,000 of contributions to the owner with $30,000 to $50,000 of employee costs. A SEP at the maximum 25 percent contribution rate delivers $72,000 to the owner but requires $125,000 of employee contributions (25 percent of $500,000 of combined employee compensation). The Safe Harbor 401(k) wins by a wide margin on cost efficiency. The cash balance plan layered on top can push the owner contribution to $200,000+ with employee costs around $50,000 to $75,000.

The best retirement plan for small business owner with high turnover or part-time employees needs eligibility rules carefully designed. SECURE 2.0 expanded coverage requirements for long-term part-time employees, requiring 401(k) participation after 2 consecutive years of working 500+ hours starting in 2025 (down from 3 years previously). The expanded coverage adds employees to the plan who might not have been eligible under prior rules, increasing the employer contribution cost. For employers with substantial part-time workforces, the rule change has material cost implications.

Our practice designs retirement plans for S corporation clients with employees regularly, and the best retirement plan for small business owner depends heavily on the specific facts. For corporations with 5-10 employees and owners earning $200,000+, the Safe Harbor 401(k) with profit sharing is the typical baseline, often with a cash balance plan layered on for owners over 45 who want to accelerate retirement savings. For very small workforces with low-paid employees, the SIMPLE can work as a transition plan before moving to a 401(k). We run the cost comparison annually for clients to confirm the plan structure still fits the current workforce and income profile, and we adjust the design when the math shifts. The plan that worked at $200,000 of owner compensation with 3 employees may not be the best fit at $400,000 of compensation with 12 employees, and proactive plan redesign captures the full available contribution capacity.

Worth flagging the SECURE 2.0 starter 401(k) for very small corporations. Under §401(k)(16), an employer can adopt a starter 401(k) plan with simplified rules: contributions are deferral-only (no employer match required), the elective deferral is capped at $6,000 for 2026 ($7,000 with catch-up), and most non-discrimination testing is waived. The starter plan is genuinely simpler than a full 401(k) but the contribution limits are too low for serious retirement savings. We rarely recommend it for clients because the trade-off (lower contributions for simpler administration) rarely makes economic sense once the owner is earning $100,000+ of W-2 wages. The plan exists primarily for very small employers who want to offer something to their employees as a benefit but cannot absorb the cost of a full 401(k).

The best retirement plan for small business owner over 55 who needs to accelerate retirement savings is almost always a defined benefit pension plan or a cash balance plan. The math works strongly in favor of older owners because the §415(b) benefit limit ($280,000 of annual retirement income for 2026) translates to higher present-value contributions when the owner is closer to retirement age. For a 55-year-old, the annual defined benefit contribution to fund the maximum benefit can run $150,000 to $200,000. For a 65-year-old, the same contribution can run $250,000 to $300,000.

The defined benefit plan works by setting a target retirement benefit, then having an enrolled actuary calculate the contribution required to fund that benefit. The actuarial calculation factors in the owner’s age, expected retirement age, expected investment return, and current and projected plan assets. The required contribution is a deductible business expense for the corporation, reduces the corporation’s net income (and the shareholder’s pass-through income), and grows tax-deferred until the owner takes distributions in retirement. The combination of the large deduction and the tax-deferred growth makes defined benefit plans extraordinarily valuable for older high-income owners.

The best retirement plan for small business owner who is 60 and earning $400,000 with 5 years until retirement at 65 is a defined benefit plan with a high benefit target. The actuarial contribution to fund a $280,000 annual benefit over 5 years can run $250,000 to $300,000 per year. The corporation contributes that amount each year, deducts it, and builds a pension balance approaching $1.5 million by retirement (plus investment returns during the funding period). The owner’s lifetime retirement income is then funded through the plan, supplemented by Social Security and other personal savings.

Cash balance plans give the same high-contribution capacity as traditional defined benefit plans but express the benefit as an account balance with annual interest credits. For older owners, the cash balance plan often pairs well with a 401(k) to capture both the elective deferral piece and the large pension contribution. A 60-year-old earning $400,000 in W-2 wages with a 401(k) plus cash balance combination can absorb $300,000+ of annual contributions: $32,500 elective deferral, $30,000 of 401(k) profit sharing, and $250,000 in cash balance contributions. The current-year federal tax savings at the 37 percent marginal rate is about $115,600, plus state and city tax savings of another $30,000 to $50,000 depending on state.

The best retirement plan for small business owner over 55 with employees gets more complicated because the plan must cover the workforce. Defined benefit plans require a minimum benefit for non-owner employees, typically 5 to 7.5 percent of compensation depending on plan design. For a corporation with 5 employees averaging $50,000 each, the employee benefit cost runs $12,500 to $18,750 per year. The total plan cost (owner contribution plus employee contributions) is high but the tax savings on the owner’s piece dwarf the employee cost. The net economics favor the plan for owners contributing $100,000+ per year.

Funding flexibility is more limited with defined benefit plans than with defined contribution plans. The actuarial contribution is a hard number each year; the corporation cannot decide to contribute less without affecting the plan’s funding status. Underfunding triggers ERISA penalties, PBGC variable rate premiums (for PBGC-covered plans), and potential disqualification of the plan. Overfunding is also a problem because the excess assets are taxed at 50 percent under §4980 on plan termination if not used for benefits. The actuary works with the corporation each year to set the contribution within a permissible range, but the flexibility is much narrower than with a Solo 401(k).

Timing matters significantly for defined benefit plans. The plan should be in place well before the owner’s retirement age to allow time for the required contributions to fund the target benefit. Establishing a defined benefit plan one year before retirement is not enough time to fund a meaningful benefit. The typical setup is 5 to 15 years before retirement, with the plan running for at least 3 to 5 years to make the administrative cost worthwhile. SECURE 2.0 expanded the ability to establish a defined benefit plan retroactively through the extended filing deadline, which helps owners who decide late in the year to set up a plan.

Plan termination at retirement requires careful planning. The plan assets are distributed to the participants (the owner and any employees) at termination, typically through rollover to IRAs. The owner’s pension balance rolls to their IRA tax-free, and subsequent distributions from the IRA are taxed at the owner’s then-current marginal rate. Required minimum distributions begin at age 73 (rising to 75 over time under SECURE 2.0). For owners who retire before age 59½, the 10 percent early withdrawal penalty under §72(t) applies unless an exception is met. Planning the distribution timing to minimize tax exposure is a key part of the retirement transition.

Our practice designs defined benefit and cash balance plans for older S corporation owners regularly, and the best retirement plan for small business owner over 55 typically involves a defined benefit or cash balance component as the primary contribution vehicle, supplemented by a 401(k) for the elective deferral piece. The combined annual contribution can exceed the §415(c) defined contribution limit by a wide margin because the defined benefit limit is calculated separately. For a 60-year-old owner with $500,000 of W-2 wages, the combined contribution capacity can reach $400,000 per year, producing current-year federal tax savings of $148,000 plus state and city tax savings. Over a 5 to 10 year funding period before retirement, the cumulative tax savings can exceed $1.5 million while building a substantial retirement asset base. The administrative cost ($4,000 to $8,000 per year for plan administration) is trivial relative to the tax savings produced.

The exit strategy for a defined benefit plan deserves dedicated planning attention. When the owner retires and the plan terminates, the lump-sum payout rolls to an IRA. The owner is then subject to RMDs starting at age 73 (rising to 75 over time). Roth conversions during the gap years between retirement and RMD age can convert traditional dollars to Roth at lower marginal rates, which is one of the most valuable post-retirement tax planning opportunities available. We model the conversion ladder for clients in advance of the plan termination so the post-retirement tax picture is clear before the lump sum lands. The combination of large pre-retirement deductions through the defined benefit plan and post-retirement Roth conversions at lower rates captures the full tax-planning value of the structure.

Retirement plan contributions interact with the §199A qualified business income deduction in ways that affect the calculation of the best retirement plan for small business owner. The §199A deduction is 20 percent of qualified business income from a pass-through entity, subject to various limitations. Retirement plan contributions made by the corporation reduce the pass-through income on which §199A is calculated, so a $50,000 retirement contribution reduces the QBI by $50,000 and reduces the §199A deduction by $10,000 (20 percent of $50,000). The current-year tax savings on the retirement contribution exceeds the lost §199A deduction at typical marginal rates, but the math is more nuanced than simple deduction analysis suggests.

For an S corporation owner with $300,000 of W-2 wages and $200,000 of pass-through income before retirement contributions, the §199A deduction at the unlimited level is $40,000 (20 percent of $200,000). A $50,000 retirement plan contribution that comes out of the pass-through income reduces QBI to $150,000 and the §199A deduction to $30,000. The net tax savings from the $50,000 contribution at a 32 percent marginal rate plus the §199A interaction is $50,000 × 32 percent (the contribution deduction) minus $10,000 × 32 percent (the lost §199A deduction), or $12,800. The effective tax savings rate on the retirement contribution is roughly 25.6 percent rather than the headline 32 percent.

The §199A wage limit makes the analysis more complicated for high-income owners. For taxpayers above the phase-out thresholds ($403,500 joint, $201,750 single for 2026), the §199A deduction is limited to the greater of (1) 50 percent of W-2 wages paid by the business, or (2) 25 percent of W-2 wages plus 2.5 percent of unadjusted basis in qualified property. The W-2 wage limit binds for service businesses (specified service trades or businesses or SSTBs are subject to the limit; certain other businesses also reach it at very high income levels). Solo 401(k) elective deferrals reduce Box 1 wages but not Box 3 wages used for the §199A wage limit calculation, which preserves the wage limit even after the deferral.

The best retirement plan for small business owner above the §199A phase-out thresholds depends on whether the business is an SSTB. SSTBs (consulting, law, accounting, financial services, performing arts, athletics, and other service businesses where the principal asset is the reputation of one or more employees) lose the §199A deduction entirely above the upper phase-out threshold ($383,900 joint, $191,950 single for 2026 fully phased out). For these high-income SSTB owners, the §199A is gone regardless of retirement contributions, so the contribution analysis ignores §199A entirely. The retirement contribution deduction is worth the full marginal rate of 37 percent federal plus state and city, which makes high contributions especially valuable.

Non-SSTB businesses (real estate operations, manufacturing, retail, distribution, most trades) above the upper phase-out threshold use the W-2 wage limit. The §199A deduction is the lesser of 20 percent of QBI or the W-2 wage formula. Retirement contributions that reduce QBI without reducing the W-2 wages preserve the wage limit. For an owner with $500,000 of QBI and $300,000 of W-2 wages, the §199A deduction is the lesser of $100,000 (20 percent of QBI) or $150,000 (50 percent of wages), so $100,000 is the deduction. Reducing QBI by $50,000 through a retirement contribution drops the QBI-based deduction to $90,000 and the §199A deduction to $90,000. The retirement contribution still saves more in current-year tax than it costs in §199A reduction.

The best retirement plan for small business owner below the §199A phase-out has the simplest math. For these taxpayers, the §199A deduction is 20 percent of QBI without any wage or property limits. A retirement contribution reduces QBI dollar-for-dollar and reduces the §199A deduction by 20 percent of the contribution. The effective marginal rate on the retirement contribution is reduced by the §199A interaction by 20 percent of the marginal rate, or roughly 5 to 7 percentage points at typical brackets. A $50,000 contribution that would have produced $16,000 of current-year savings (at 32 percent marginal) actually produces about $13,800 of net savings after the §199A interaction. Still positive but smaller than the headline rate suggests.

Cash balance plans and defined benefit plans amplify the §199A interaction because the contributions are typically much larger. A $200,000 defined benefit contribution that reduces QBI by $200,000 reduces the §199A deduction by $40,000. At a 32 percent marginal rate, the §199A loss is $12,800. The contribution still produces $64,000 of current-year federal tax savings (32 percent of $200,000), so the net is $51,200. Plus state and city tax savings of another $30,000 to $40,000. The total current-year savings on a $200,000 defined benefit contribution can exceed $80,000 to $90,000 in NYC, which is enough to pay for several years of retirement plan administrative fees.

savings between W-2 wages and retirement contributions matters at the margin. For S corporation owners with W-2 wages set at the reasonable comp minimum and pass-through income above the §199A thresholds, increasing W-2 wages can increase the W-2 wage limit and preserve the §199A deduction even when retirement contributions reduce QBI. The trade-off is that higher W-2 wages mean higher payroll tax exposure under §3121 and §3401. The optimal split between wages and pass-through income depends on the specific income level, the marginal rates, and the §199A interaction. We run the savings annually for clients to set the wages and the retirement contribution to make the most of the after-tax outcome.

Our practice models the §199A interaction with retirement contributions for S corporation clients each year. The best retirement plan for small business owner is rarely changed by §199A alone, but the contribution size sometimes is. For owners well below the §199A thresholds, contribution decisions are made independently of §199A. For owners in the phase-out range, the §199A interaction can shift the optimal contribution by $10,000 to $30,000 per year. For owners above the upper phase-out (especially SSTB owners), §199A is no longer a factor and the retirement contribution decision is driven by ordinary marginal rate analysis. The differential between an improved retirement contribution and a default contribution can be $5,000 to $15,000 of current-year tax savings, which justifies the annual planning conversation. The best retirement plan for small business owner is whichever plan, sized appropriately, captures the most after-tax value across the owner’s specific income and §199A position.

The best retirement plan for small business owner has deadlines that vary by plan type and contribution component. For Solo 401(k) plans, the plan itself must be established by December 31 of the year for which contributions will be made. SECURE 2.0 allowed some flexibility for plans established after year-end with retroactive employer contributions, but elective deferrals still require the plan to exist by year-end. The employee elective deferral must be made through payroll deduction during the year (with the actual transfer to the custodian within 7 business days for plans with fewer than 100 participants). The employer contribution can be made through the corporation’s extended filing deadline (October 15 for an S corporation that filed an extension).

SEP-IRA contributions have the most flexible deadline. The plan can be established and funded as late as the corporation’s extended filing deadline (October 15 for an S corporation that extended). This is unique among retirement plans; most others require the plan to be in place by year-end. The flexibility allows the corporation to see the year’s results, decide on the contribution amount, and establish the plan retroactively in the following October if desired. For owners who are uncertain about their year-end results, the SEP is the most forgiving plan to set up.

The best retirement plan for small business owner using a SIMPLE IRA has specific October 1 timing. The SIMPLE must be established by October 1 of the year for which it will be effective. A new SIMPLE cannot be set up after October 1 for the current year; the corporation must wait until the following year. Employee elective deferrals through payroll deduction must be transferred to the custodian within 30 days of the payroll date. Employer matching contributions can be made through the corporation’s extended filing deadline. The October 1 establishment deadline is the SIMPLE’s main inflexibility relative to other plans.

Defined benefit plans follow the corporate filing deadline including extensions for contributions, but the plan documents must be in place by the year-end for which the contribution is intended. SECURE 2.0 expanded the ability to adopt a defined benefit plan retroactively through the extended filing deadline. The actuarial certification of the contribution must be completed before the contribution is made, which requires the actuary to receive the prior year’s plan information and the current year’s compensation and demographic data. The typical timing is a December or January meeting with the actuary to set the current-year contribution, contribution in the spring or summer based on the actuarial recommendation.

Form 5500 annual filing is required for most retirement plans. The Form 5500 reports plan assets, contributions, distributions, and participant counts. The deadline is the last day of the seventh month after the plan year-end (July 31 for a calendar-year plan), with a one-time 2.5-month extension available on Form 5558 (filed by July 31 to extend to October 15). The form has different variants: Form 5500 for plans with 100+ participants, Form 5500-SF for small plans, and Form 5500-EZ for one-participant plans with assets over $250,000. Missing the Form 5500 deadline triggers DOL penalties up to $2,710 per day under ERISA §502(c)(2).

Solo 401(k) plans with assets under $250,000 at year-end have no Form 5500 filing requirement. Above $250,000, the Form 5500-EZ is required. The form is short (4 pages) and asks for basic plan information, contribution totals, and asset values. Plan custodians provide the year-end statement that has the necessary information. Most plan documents also require the plan administrator (typically the corporation) to maintain plan documents, amendments, and participant records. The administrative burden is genuinely minimal for a single-participant plan, but it is not zero.

Plan documents must be amended periodically to comply with changes in the Code and regulations. SECURE 2.0 introduced many changes (Roth treatment of employer contributions, expanded catch-up for ages 60-63, etc.) that require plan document amendments. The IRS has provided a remedial amendment period for these changes, typically through December 31, 2025 or later for most provisions. After the remedial period, plan amendments must be adopted by the deadlines specified in the relevant guidance. Plan custodians typically handle the amendments for their pre-approved documents, but the corporation should confirm the amendments are being adopted timely.

Distributions from retirement plans have their own deadlines and reporting. Required minimum distributions begin at age 73 under SECURE 2.0 (rising to 75 by 2033). The first RMD is due by April 1 of the year after the participant turns 73. Subsequent RMDs are due by December 31 each year. Missing an RMD triggers a 25 percent excise tax under §4974 (reduced from 50 percent by SECURE 2.0), with the option to reduce to 10 percent if corrected within the correction window. The 1099-R reporting requirements apply to all distributions, and the plan administrator (typically the custodian for self-directed plans) handles the issuance.

Our practice tracks the calendar of retirement plan deadlines for clients each year to make sure nothing slips. The best retirement plan for small business owner from a compliance perspective is the one whose deadlines fit the corporation’s other compliance rhythms. For most S corp clients, the cycle is: December to January meeting to set wages, retirement contributions, and other year-end planning. February to March for the prior year’s contribution finalization. March 15 for Form 1120-S filing (or extension to September 15). October 15 for any extended retirement contributions. July 31 (or extended October 15) for Form 5500. The administrative cycle is predictable and the deadlines are met on a rhythm. Skipping deadlines or trying to retroactively establish plans after the fact creates compliance gaps that are harder to fix than maintaining the regular schedule. The best retirement plan for small business owner is the one that gets set up correctly on time and maintained without drama through the years of contribution and accumulation.

One additional administrative point that catches owners off-guard: required notices. Safe Harbor 401(k) plans require an annual notice to participants by December 1 describing the safe harbor contribution and employee rights. Automatic enrollment plans require their own notices. Defined benefit plans require annual funding notices under ERISA §101(f). Missing these notices does not always trigger immediate penalties but it does create a compliance defect that the IRS or DOL can use to disqualify the plan in an audit. Most plan administrators handle the notices automatically, but the corporation should confirm the notices are going out each year. We add notice distribution to the year-end checklist for every client with an employee-covered plan, alongside the contribution funding and Form 5500 prep.