White Coat Investor Podcast #443: From TSP to Solo 401(k): Real-Life Retirement Planning Questions Answered
Host: Dr. Jim Dahle
Date: October 30, 2025

Episode Overview

In this episode, Dr. Jim Dahle fields a series of listener questions that span the practical realities of moving funds out of the Thrift Savings Plan (TSP), navigating traditional vs. Roth retirement account options, handling deferred compensation plans (like the 457), nuances of using ETFs versus mutual funds, understanding 401(k) matches and true-ups, merging finances and IRA rollovers after marriage, and fine points on calculating Solo 401(k) contributions. Dr. Dahle brings his signature candid, no-nonsense approach, sharing both technical detail and practical wisdom for high-income professionals on their path to financial independence.

Key Discussion Points & Insights

1. Rolling Over the Roth TSP After Military Service ([01:34 – 05:50])

• Listener’s Question: Is there any real reason to keep money in the Roth TSP or should I roll it into a Roth IRA, despite the famed G Fund?
• Dr. Dahle’s Response:
  • The TSP used to be the best 401(k) due to extremely low expense ratios and unique funds, especially the G Fund.
  • The G Fund: Unique to TSP and offers Treasury bond yields with money market-like risk.
    • “The TSP basically gives you Treasury bond yield for money market risk. … The G Fund is unique to the TSP. There really is nothing that compares to it out there.” (03:35)
  • If you don’t specifically plan to use the G Fund, it’s fine to roll funds to a Roth IRA for simplicity.
  • Stick to reputable brokerages (Vanguard, Fidelity, Schwab), be wary of “gamified” platforms offering bonuses.
  • Other employer 401(k)s have improved, reducing TSP’s relative advantage.
  • Takeaway: Rolling over is reasonable if not interested in the G Fund, particularly for account simplification.

2. Marginal vs. Effective Tax Rate: Roth vs. Traditional Contributions ([07:53 – 12:47])

• Listener’s Question: When deciding between Roth and Traditional (pre-tax) contributions, should you compare your marginal tax rate now to your marginal or effective rate in retirement?
• Dr. Dahle’s Clarification:
  • The academically correct comparison is marginal to marginal: marginal rate at contribution vs. marginal at withdrawal—"for every dollar."
    • “The academically correct answer is it’s marginal to marginal. … That’s the academically correct answer.” (10:57)
  • References to effective rate are to remind that retirement withdrawals often fill the lower tax brackets first, effectively lowering overall tax.
  • Complex, individualized decision; both Roth and Traditional options have merits. Factors can be unknown/unknowable in advance.
  • Memorable Quote: “Anybody that tells you this is simple or that the right answer is always the same thing, they don’t understand the issue. It’s complicated.” (08:44)
  • If interested, see Dr. Dahle’s March 7, 2025 post, “Should You Do Roth Contributions and Conversions?” on whitecoatinvestor.com.

3. Deferred Compensation Plans & When to Use Them ([13:02 – 19:37])

• Listener’s Question: Should I maximize a deferred compensation (457) plan and what can be done with the distributions, especially while in a high income bracket?
• Dr. Dahle’s Insights:
  • Two Types of 457 Plans:
    1. Governmental: Money held in trust; can roll to an IRA/401(k); secure from employer creditors.
    2. Non-Governmental (Tax Exempt): Not held in trust; at risk to employer’s creditors (e.g., recent Steward bankruptcy case); limited, sometimes awkward withdrawal options.
    • “You definitely want to look at the employer’s, you know, financial stability when you’re contributing to these things.” (17:04)
  • Withdrawal options often rigid; must check if you can spread distributions or are forced to take lump sums while still employed.
  • Often used for early retirement withdrawals (before age 59.5).
  • Practical Advice: Governmental 457s are generally safe to maximize; use caution with non-governmental versions—risk of loss, withdrawal mechanics, and psychological stress (worrying if your money is safe).
  • Max out qualified accounts first; use taxable after if not comfortable with deferred comp risks.

4. Dealing with Multiple Brokerages & ETFs vs. Mutual Funds ([19:44 – 24:18])

• Listener’s Issue: Hates idle cash from ETF purchases across accounts and is annoyed by small cash leftovers; wonders if consolidating to mutual funds at fewer brokerages is better.
• Dr. Dahle’s Wisdom:
  • The frustration is relatable—a minor “OCD” issue many feel.
  • Limit orders rarely justify the time or risk of missing an investment window for such liquid ETFs.
  • “Get a grip on your ocdness, right?” (21:54)
  • Recommends using market orders for very liquid ETFs; minor cash drag is insignificant long-term.
  • On Brokerages: Having accounts at multiple places is common; using uniform ETFs (like VTI, VXUS, ITOT) ensures simplification without consolidation.
  • “It’s okay to have a little bit of money sitting in cash in every account. It’s not going to break the bank or anything.” (24:05)

5. Understanding 401(k) Match ‘True Ups’ ([24:23 – 27:59])

• Listener’s Scenario: Lost out on part of an employer match after adjusting per-paycheck contributions; employer had to “true up” at year-end.
• Dr. Dahle’s Take:
  • Many employees don’t realize employer matches can be affected by how you sequence contributions during the year.
  • Some plans require even contributions per paycheck to get the full match unless a “true up” (employer catch-up) is performed.
  • Action Items:
    • “Go into HR, get the 401k document, read the stupid thing. It’s your retirement we’re talking about.” (26:08)
    • Explicitly confirm with HR how matching and true-up mechanics work for your plan.

6. Merging Finances After Marriage: Rolling Over IRA or Converting to Roth? ([28:46 – 32:26])

• Ben in PA Scenario: Wife returning to school, low income this year, $80K IRA—should they roll into a Solo 401(k) or convert to Roth, to allow for future backdoor Roth contributions?
• Dr. Dahle’s Perspective:
  • Both are “the right thing,” but which is optimal depends on unknowable factors (future income, tax rates, etc.).
  • Roth conversion would cost $25–30K in taxes now, but locks in tax-free compounding.
    • “The fact that she’s in school suggests to me that she may have higher income later, which might suggest … that Roth conversion is actually a pretty good idea if you can afford it.” (31:42)
  • Rolling into Solo 401(k) sidesteps a high tax bill, enables backdoor Roth, and retains flexibility.
  • “Don’t beat yourself up too much about it … either one of them is a good option.” (31:29)
  • Strongly suggests reading the “Roth contributions” article from WCI for deeper factors.

7. Calculating Solo 401(k) Contributions Correctly ([32:31 – 35:08])

• Craig’s Technical Question: Is the employee emoyer contribution really 20% of net profit, or do you need to subtract half of self-employment tax first?
• Dr. Dahle’s Clarification:
  • Correct method: 20% of net business income minus the employer portion of self-employment tax.
    • “It’s 20% of your net income. … Net of the employer portion of self employment taxes.” (33:47)
  • Make sure to calculate on the post-SE-tax amount; not simply the Schedule C bottom line.
  • Reminds of three types of 401(k) contributions: employee deferral, employer, and after-tax (mega backdoor Roth)—know your plan’s capabilities.

Notable Quotes & Memorable Moments

• On TSP’s G Fund: “The G Fund is unique to the TSP. There really is nothing that compares to it out there.” (03:35)
• On Roth vs. Traditional: “Anybody that tells you this is simple or that the right answer is always the same thing, they don’t understand the issue. It’s complicated.” (08:44)
• On Non-Governmental 457s: “You definitely want to look at the employer’s, you know, financial stability when you’re contributing to these things.” (17:04)
• On ETF Cash Drag: “Get a grip on your ocdness, right?” (21:54)
• On 401(k) Match Documentation: “Go into HR, get the 401k document, read the stupid thing. It’s your retirement we’re talking about.” (26:08)
• On Decision Paralysis: “Don’t beat yourself up too much about it … either one of them is a good option.” (31:29)

Community and Resource Reminders ([06:00–07:44], [36:35–38:42])

• Extensive WCI communities exist on Reddit, Facebook, the Forum, and Instagram—crowdsource your personal finance questions.
• Dr. Dahle encourages listeners to give and get support, pay it forward, and educate peers.

Timestamps for Important Sections

• [01:34] – TSP to Roth IRA rollover/G Fund uniqueness
• [07:53] – Marginal vs. effective tax rate in Roth vs. Traditional decisions
• [13:02] – Deferred comp plans (457), employer bankruptcy risk, distribution options
• [19:44] – ETFs vs. mutual funds, managing cash at multiple brokerages
• [24:23] – 401(k) match “true up” scenarios and avoiding lost employer matches
• [28:46] – Merging finances: IRA to Roth conversion vs. Solo 401(k)
• [32:31] – Solo 401(k) calculation: self-employment tax nuance

Final Thoughts and Tone

Dr. Dahle reiterates the importance of prudent financial habits, continuing education, and participation in community for support and knowledge sharing. He acknowledges the difficult, often unknowable nature of some key financial decisions and encourages listeners not to stress over perfection when both options are fundamentally sound. The tone remains collegial, pragmatic, and supportive, with a mix of technical rigor and down-to-earth advice—a hallmark of WCI’s style.

For deeper dives and written references, search whitecoatinvestor.com for articles on “Roth contributions” and specific plan rules. Join a WCI community group to crowdsource your next financial question.