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An advisor’s guide to the benefits of solo 401(k)s

As you work with self-employed clients, here are five big reasons why a solo 401(k) may be right for them (and your firm).

By Betterment Editors

Published Feb. 27, 2025

An advisor’s guide to the benefits of solo 401(k)s Feb 27, 2025 8:00:00 AM As you work with self-employed clients, here are five big reasons why a solo 401(k) may be right for them (and your firm). A solo 401(k) might just be the biggest retirement savings growth hack for your self-employed clients — and you can help them navigate it. As more people shift toward freelance work, consulting, and small business ownership, RIAs are increasingly asked about retirement planning by clients who don’t fit the traditional W-2 profile. Enter the solo 401(k): A lesser-known retirement account that just might be the ultimate savings vehicle for self-employed clients of RIAs. However, many advisors overlook the solo 401(k) or assume it’s too complex. In reality, it can be a straightforward, flexible, and powerful option for those who have no full-time employees beyond themselves (and possibly a spouse). The basics: What exactly is a solo 401(k)? A solo 401(k) is a one-participant 401(k) plan for self-employed individuals of owner-only businesses. It works similarly to a standard 401(k)—with employee and employer contribution components—but is designed specifically for businesses that do not have full-time employees other than a spouse. It’s different from SEP IRAs (which only allow employer contributions) and SIMPLE IRAs (with lower contribution limits). For many advisors (and their clients) who are less familiar with solo 401(k)s, two misconceptions commonly get in the way of using one for savings: “Solo 401(k)s are too complicated.” Some solo 401(k) providers (like Betterment Advisor Solutions) offer streamlined setup and modern digital account management. This makes it simple to manage. Once the plan is established, annual maintenance is often minimal—though advisors and participants should be mindful of certain administrative requirements, such as filing Form 5500 once the plan balance exceeds $250,000. “They’re only for high-income earners.” Contribution limits are high (we’ll cover more on that in a minute), but that doesn’t mean a lower-income entrepreneur can’t benefit. Contributions are flexible each year, so clients can scale up or down depending on business performance. Solo 401(k)s are really a simple way for self-employed individuals to save for retirement. And, they offer some added financial benefits that savers can’t get through other plans. Top 5 benefits of solo 401(k)s for your clients As you work with self-employed clients, here are five big reasons why a solo 401(k) may be right for them (and your firm). Benefit 1: solo 401(k)s are tailored for solo entrepreneurs Sole proprietors, consultants, and gig workers have unique needs. They’re juggling business expenses, unpredictable income streams, and personal financial goals. A solo 401(k) allows them to save aggressively in profitable years, and dial back contributions if cash flow tightens. Solo 401(k)s also have the added benefit of allowing spousal contributions. If a spouse is also on the payroll, he or she can contribute just like the primary business owner. This effectively doubles the family’s retirement savings potential and can significantly reduce household taxable income if making pre-tax contributions. What does this mean for advisors? More opportunity. The rise of online platforms, remote work, and freelance marketplaces means self-employment is only becoming more popular. In fact, conservative figures estimate that there are 16 million self-employed Americans. By offering guidance on solo 401(k)s, you can expand your practice to a growing client segment that often has questions about retirement planning but limited employer-sponsored options. Your firm can offer an opportunity they may not have realized they had. Benefit 2: High contribution limits One of the biggest draws of the solo 401(k) is the dual role contribution approach: Employee contribution: In 2025, individuals can contribute up to 100% of compensation or $23,500 (or $31,000 if age 50 or over). Employer contribution: As the business owner, they can also contribute up to 25% of net self-employment income (20% for sole proprietors/partnerships). Total contributions to a participant’s account, not counting catch-up contributions for those age 50 and over, cannot exceed $70,000 for tax year 2025. Combined, dual-role contributions can lead to substantially larger total contributions than are available through SEP IRAs or SIMPLE IRAs. For instance, a SEP IRA lacks the employee deferral option, so having both an employee and employer bucket in a solo 401(k) can help maximize tax-advantaged savings. Benefit 3: Tax advantages The tax benefits are very real when it comes to solo 401(k)s. By helping clients understand these benefits, you can have a significant impact on their tax burden, both now and in retirement. Pre-tax contributions: Similar to a traditional 401(k), clients who want immediate tax relief can fund their solo 401(k) with pre-tax dollars, reducing their current taxable income. This is particularly appealing to self-employed individuals, looking to lower their overall tax burden in years of high income. Roth contributions: Many solo 401(k) providers now allow Roth contributions. This means after-tax money goes in, but withdrawals in retirement are generally tax free. Offering both pre-tax and Roth options gives clients flexibility in managing their present and future tax situations. SECURE 2.0 Automatic Enrollment Tax Credit: Many miss this one, but under the SECURE 2.0 Act, if an eligible solo 401(k) adds an auto-enrollment feature to their plan, they can claim a tax credit of $500 per year for 3 years. Benefit 4: No income restrictions on contributions Unlike Roth IRAs, which have strict income limits, solo 401(k)s do not cap your ability to make Roth contributions based on income. High earners who would be locked out of a Roth IRA can still enjoy the potential for tax-free growth through a Roth solo 401(k). And let’s not forget about catch-up contributions: For clients over 50, an additional $7,500 (as of 2024) can be contributed to the employee deferral portion. This “catch-up” feature allows those who got a late start on saving to accelerate their retirement funding. Benefit 5: Prior year contributions for new plans The SECURE Act 2.0 introduced a key benefit for solo 401(k) plans: Business owners can establish a solo 401(k) by the previous year's tax filing deadline (including extensions). Employer contributions for the prior calendar year can be made up until the business’s tax filing deadline. Example: How prior contributions work If your client sets up a new solo 401(k) in March 2024, it can still count as a 2023 plan. Your client can make 2023 employer contributions until April 15, 2024 (or October 15 if they file an extension). This is a powerful opportunity for clients to catch up on retirement savings they might have overlooked during a busy year. Adding value: The advisor's role in a client’s solo 401(k) Although solo 401(k)s can be self-directed by a client, you have an opportunity to add value by guiding your client to the right plan for their overall retirement needs. Here are four ways your firm can help clients navigate solo 401(k)s: Contribution strategy: Help clients determine whether pre-tax or Roth contributions (or a mix) best suit their goals. Timing contributions strategically—especially near tax deadlines—can optimize tax savings and cash flow. Investment guidance: solo 401(k)s often offer a wide range of investment options. Advisors can provide asset allocation and diversification strategies based on each client’s risk tolerance and timeline. IRS rules and compliance: While solo 401(k)s are relatively straightforward, there are filing requirements (e.g., Form 5500 for account balances above $250,000) and rules about loans from the plan. Advisors can help keep clients on track. Long-term retirement planning: A solo 401(k) should be one part of a holistic retirement strategy. Advisors can integrate Social Security planning, insurance, and estate considerations to round out a client’s financial picture. Tips for getting started: Choosing a solo 401(k) provider When recommending or setting up a plan for your clients, look for a provider that offers transparent fees, an intuitive digital experience, and proven knowledge in compliance and recordkeeping. Also, consider the breadth of services a provider offers. Some providers also offer tools for RIAs, like custodial services or portfolio management, which can streamline your overall practice management. Introducing the Betterment solo 401(k) The Betterment solo 401(k) integrates smoothly with our all-in-one custodial platform purpose-built for independent RIAs. Modern, digital-first experience: Simplify plan set-up and ongoing management with a 100% digital process. We eliminate the administrative burden traditionally associated with solo 401(k)s by digitally opening and funding accounts with no paperwork required. Seamless ongoing management: We provide compliance support for your firm with no need to manually track contributions. Cost-effective plans: Minimize costs while maximizing savings potential for your self-employed clients. Give clients access to low-cost investments paired with the high contribution limits of a solo 401(k). Plus, clients can include spouses at no additional cost. Roth solo 401(k) option: Give your clients the flexibility to optimize their taxes by using a traditional solo 401(k) or a Roth, whatever is best for their situation.

A solo 401(k) might just be the biggest retirement savings growth hack for your self-employed clients — and you can help them navigate it.

As more people shift toward freelance work, consulting, and small business ownership, RIAs are increasingly asked about retirement planning by clients who don’t fit the traditional W-2 profile.

Enter the solo 401(k): A lesser-known retirement account that just might be the ultimate savings vehicle for self-employed clients of RIAs. However, many advisors overlook the solo 401(k) or assume it’s too complex. In reality, it can be a straightforward, flexible, and powerful option for those who have no full-time employees beyond themselves (and possibly a spouse).

The basics: What exactly is a solo 401(k)?

A solo 401(k) is a one-participant 401(k) plan for self-employed individuals of owner-only businesses.

It works similarly to a standard 401(k)—with employee and employer contribution components—but is designed specifically for businesses that do not have full-time employees other than a spouse.
It’s different from SEP IRAs (which only allow employer contributions) and SIMPLE IRAs (with lower contribution limits).

For many advisors (and their clients) who are less familiar with solo 401(k)s, two misconceptions commonly get in the way of using one for savings:

“Solo 401(k)s are too complicated.” Some solo 401(k) providers (like Betterment Advisor Solutions) offer streamlined setup and modern digital account management. This makes it simple to manage. Once the plan is established, annual maintenance is often minimal—though advisors and participants should be mindful of certain administrative requirements, such as filing Form 5500 once the plan balance exceeds $250,000.
“They’re only for high-income earners.” Contribution limits are high (we’ll cover more on that in a minute), but that doesn’t mean a lower-income entrepreneur can’t benefit. Contributions are flexible each year, so clients can scale up or down depending on business performance.

Solo 401(k)s are really a simple way for self-employed individuals to save for retirement. And, they offer some added financial benefits that savers can’t get through other plans.

Top 5 benefits of solo 401(k)s for your clients

Benefit 1: solo 401(k)s are tailored for solo entrepreneurs

Sole proprietors, consultants, and gig workers have unique needs. They’re juggling business expenses, unpredictable income streams, and personal financial goals. A solo 401(k) allows them to save aggressively in profitable years, and dial back contributions if cash flow tightens.

Solo 401(k)s also have the added benefit of allowing spousal contributions. If a spouse is also on the payroll, he or she can contribute just like the primary business owner. This effectively doubles the family’s retirement savings potential and can significantly reduce household taxable income if making pre-tax contributions.

What does this mean for advisors? More opportunity.

The rise of online platforms, remote work, and freelance marketplaces means self-employment is only becoming more popular. In fact, conservative figures estimate that there are 16 million self-employed Americans. By offering guidance on solo 401(k)s, you can expand your practice to a growing client segment that often has questions about retirement planning but limited employer-sponsored options. Your firm can offer an opportunity they may not have realized they had.

Benefit 2: High contribution limits

One of the biggest draws of the solo 401(k) is the dual role contribution approach:

Employee contribution: In 2025, individuals can contribute up to 100% of compensation or $23,500 (or $31,000 if age 50 or over).
Employer contribution: As the business owner, they can also contribute up to 25% of net self-employment income (20% for sole proprietors/partnerships).

Total contributions to a participant’s account, not counting catch-up contributions for those age 50 and over, cannot exceed $70,000 for tax year 2025.

Combined, dual-role contributions can lead to substantially larger total contributions than are available through SEP IRAs or SIMPLE IRAs. For instance, a SEP IRA lacks the employee deferral option, so having both an employee and employer bucket in a solo 401(k) can help maximize tax-advantaged savings.

Benefit 3: Tax advantages

The tax benefits are very real when it comes to solo 401(k)s. By helping clients understand these benefits, you can have a significant impact on their tax burden, both now and in retirement.

Pre-tax contributions: Similar to a traditional 401(k), clients who want immediate tax relief can fund their solo 401(k) with pre-tax dollars, reducing their current taxable income. This is particularly appealing to self-employed individuals, looking to lower their overall tax burden in years of high income.
Roth contributions: Many solo 401(k) providers now allow Roth contributions. This means after-tax money goes in, but withdrawals in retirement are generally tax free. Offering both pre-tax and Roth options gives clients flexibility in managing their present and future tax situations.
SECURE 2.0 Automatic Enrollment Tax Credit: Many miss this one, but under the SECURE 2.0 Act, if an eligible solo 401(k) adds an auto-enrollment feature to their plan, they can claim a tax credit of $500 per year for 3 years.

Benefit 4: No income restrictions on contributions

Unlike Roth IRAs, which have strict income limits, solo 401(k)s do not cap your ability to make Roth contributions based on income. High earners who would be locked out of a Roth IRA can still enjoy the potential for tax-free growth through a Roth solo 401(k).

And let’s not forget about catch-up contributions: For clients over 50, an additional $7,500 (as of 2024) can be contributed to the employee deferral portion. This “catch-up” feature allows those who got a late start on saving to accelerate their retirement funding.

Benefit 5: Prior year contributions for new plans

The SECURE Act 2.0 introduced a key benefit for solo 401(k) plans:

Business owners can establish a solo 401(k) by the previous year's tax filing deadline (including extensions).
Employer contributions for the prior calendar year can be made up until the business’s tax filing deadline.

Example: How prior contributions work

If your client sets up a new solo 401(k) in March 2024, it can still count as a 2023 plan. Your client can make 2023 employer contributions until April 15, 2024 (or October 15 if they file an extension). This is a powerful opportunity for clients to catch up on retirement savings they might have overlooked during a busy year.

Adding value: The advisor's role in a client’s solo 401(k)

Although solo 401(k)s can be self-directed by a client, you have an opportunity to add value by guiding your client to the right plan for their overall retirement needs.

Here are four ways your firm can help clients navigate solo 401(k)s:

Contribution strategy: Help clients determine whether pre-tax or Roth contributions (or a mix) best suit their goals. Timing contributions strategically—especially near tax deadlines—can optimize tax savings and cash flow.
Investment guidance: solo 401(k)s often offer a wide range of investment options. Advisors can provide asset allocation and diversification strategies based on each client’s risk tolerance and timeline.
IRS rules and compliance: While solo 401(k)s are relatively straightforward, there are filing requirements (e.g., Form 5500 for account balances above $250,000) and rules about loans from the plan. Advisors can help keep clients on track.
Long-term retirement planning: A solo 401(k) should be one part of a holistic retirement strategy. Advisors can integrate Social Security planning, insurance, and estate considerations to round out a client’s financial picture.

Tips for getting started: Choosing a solo 401(k) provider

When recommending or setting up a plan for your clients, look for a provider that offers transparent fees, an intuitive digital experience, and proven knowledge in compliance and recordkeeping. Also, consider the breadth of services a provider offers. Some providers also offer tools for RIAs, like custodial services or portfolio management, which can streamline your overall practice management.

Introducing the Betterment solo 401(k)

The Betterment solo 401(k) integrates smoothly with our all-in-one custodial platform purpose-built for independent RIAs.

Modern, digital-first experience: Simplify plan set-up and ongoing management with a 100% digital process. We eliminate the administrative burden traditionally associated with solo 401(k)s by digitally opening and funding accounts with no paperwork required.
Seamless ongoing management: We provide compliance support for your firm with no need to manually track contributions.
Cost-effective plans: Minimize costs while maximizing savings potential for your self-employed clients. Give clients access to low-cost investments paired with the high contribution limits of a solo 401(k). Plus, clients can include spouses at no additional cost.
Roth solo 401(k) option: Give your clients the flexibility to optimize their taxes by using a traditional solo 401(k) or a Roth, whatever is best for their situation.