在本期《Motley Fool Hidden Gems 投资播客》的周六个人理财特辑中，主持人罗伯特·布罗坎普将本集致力于探讨401k计划中一些独特、鲜为人知且经常未被充分利用的功能，此前不久是2026年9月10日的全国401k日。他在讨论开始前指出，并非所有401k计划都提供这些功能，但他鼓励听众如果他们的计划缺乏这些功能，可以向雇主询问是否可以添加。 讨论的第一个功能是**自主管理型经纪账户**。这允许参与者投资标准401k计划中典型的15-25种共同基金之外的资产。此类账户可以提供更广泛的共同基金、个股或债券的投资选择。尽管约有20%至30%的401k计划包含此功能，但只有1%至3%的符合条件的参与者实际使用它，这通常是由于缺乏了解。布罗坎普强调，计划提供者可能因信托责任而犹豫是否提供此类账户，他们担心员工可能会做出不慎重的投资选择。然而，他认为更多的选择有利于投资者，使他们能够追求个股、更广泛的股票基金和ETF，甚至为其投资组合中非股票部分寻找更复杂的选择，而不仅仅局限于一两种基本债券基金。他敦促听众检查其计划的功能，如果此选项不可用，则要求添加。 接下来，布罗坎普深入探讨了**巨额后门罗斯**策略。他首先提醒听众标准的401k供款限额（2026年为24,500美元，加上50岁及以上人士的追加供款）。然而，他指出一个鲜为人知的总限额：2026年，总供款（员工的传统/罗斯供款、雇主配对供款、利润分享）最高可达72,000美元（加上追加供款金额）。如果员工的合计供款低于这个更高的限额，他们可以通过**税后供款**来补足差额，前提是他们的计划允许这样做。这些税后供款是已纳税的，其增长是税收递延的。尽管供款本身在提款时是免税的，但任何收益都会作为普通收入征税，这可能看起来不如应税经纪账户有吸引力。 “巨额后门”的实现是通过转换来实现的。离开雇主时，税后供款可以转入罗斯IRA（免税），而产生的收益可以转入传统IRA。这使得罗斯IRA未来的所有增长和提款都免税，并避免了**强制性最低提款 (RMDs)**。更好的是，一些401k计划允许在受雇期间进行**计划内罗斯转换**或转账。这使得参与者可以将他们的税后供款转换为401k内的罗斯资产。转换税后本金通常是免税的，但转换这笔钱产生的任何收益都是应税的。因此，理想的做法是尽快转换这些供款，最好通过一些计划提供的自动每日或按薪转换，以最大程度地减少应税收益。布罗坎普提醒说，这项策略复杂，需要谨慎执行，通常需要寻求金融专业人士的建议。一个主要的障碍是，许多计划由于**非歧视性测试**而未能提供税后供款或计划内转换，该测试旨在防止计划不成比例地惠及高薪员工。如果没有足够的非高薪员工进行税后供款，高薪员工的税后供款可能会被退还。 最后，布罗坎普讨论了**55岁规则**，这是在59岁半之前从税收优惠账户提前提款通常会遭受10%罚款的一个例外。这项规则特别适用于401k计划（以及类似的计划，如403b计划和联邦节俭储蓄计划）。如果员工在年满55岁的日历年或之后离职（无论是自愿还是非自愿），他们可以从*该特定401k计划*中提款，而无需承担10%的提前分配罚款。关键条件适用：它仅涵盖员工在年满55岁或以上时参与的计划，并且资金必须保留在该雇主的计划中；将其转入IRA或新雇主的计划将丧失此项福利。旧的401k计划可以在离职前转入当前雇主的计划，以便根据此规则整合资金。对于一些合格的公共安全员工，存在一个增强版本，允许在50岁或服务满25年后（以较早者为准）进行免罚款分配。务必记住，虽然55岁规则免除了罚款，但提款所适用的所得税仍然适用。 布罗坎普最后重申了理解这些功能的重要性，并倡导将其纳入个人的职场退休计划。

On this Saturday Personal Finance Edition of the Motley Fool Hidden Gems Investing Podcast, host Robert Brokamp dedicated the episode to exploring a few unique, lesser-known, and often underutilized features of 401k plans, following the recent National 401k Day on September 10th, 2026. He prefaced the discussion by noting that not all 401ks offer these features, but encouraged listeners to inquire with their employers about adding them if their plans are lacking. The first feature discussed is the **self-directed brokerage account**. This allows participants to invest beyond the typical 15-25 mutual funds offered in standard 401ks. Such accounts can provide access to a broader range of mutual funds, individual stocks, or bonds. While about 20% to 30% of 401k plans include this feature, only 1% to 3% of eligible participants actually use it, often due to lack of awareness. Brokamp highlighted that plan providers might be hesitant to offer these accounts due to fiduciary responsibilities, fearing employees might make imprudent investment choices. However, he argued that more choices benefit investors, allowing them to pursue individual stocks, a wider array of stock funds and ETFs, or even more sophisticated options for the non-stock portion of their portfolio beyond just one or two basic bond funds. He urged listeners to check their plan's features and request this option if it's not available. Next, Brokamp delved into the **mega backdoor Roth** strategy. He began by reminding listeners of the standard 401k contribution limits ($24,500 for 2026, plus catch-up contributions for those 50 and older). However, he pointed out a less-known overall limit: in 2026, total contributions (employee's traditional/Roth, employer match, profit-sharing) can go up to $72,000 (plus catch-up amounts). If an employee's combined contributions fall below this higher limit, they might be able to contribute the difference via **after-tax contributions**, provided their plan allows it. These after-tax contributions are post-tax, and their growth is tax-deferred. While the contributions themselves are tax-free upon distribution, any gains are taxed as ordinary income, which might seem less appealing than a taxable brokerage account. The "mega backdoor" aspect comes into play through conversions. When leaving an employer, after-tax contributions can be rolled into a Roth IRA (tax-free), and the attributable gains into a traditional IRA. This makes all future growth and distributions from the Roth IRA tax-free and avoids Required Minimum Distributions (RMDs). Even better, some 401k plans allow for **in-plan Roth conversions** or transfers while still employed. This enables participants to convert their after-tax contributions into Roth assets within the 401k. Converting the after-tax basis is generally tax-free, but converting any earnings on that money is taxable. Therefore, it's ideal to convert these contributions as quickly as possible, ideally through automatic daily or per-payroll conversions offered by some plans, to minimize taxable earnings. Brokamp cautioned that this strategy is complex and requires careful execution, often warranting advice from a financial professional. A significant hurdle is that many plans don't offer after-tax contributions or in-plan conversions due to **non-discrimination testing**, which prevents plans from disproportionately benefiting highly compensated employees. If not enough non-highly compensated employees make after-tax contributions, highly compensated employees might have theirs refunded. Finally, Brokamp discussed the **Rule of 55**, an exception to the usual 10% penalty for early withdrawals from tax-advantaged accounts before age 59½. This rule applies specifically to 401ks (and similar plans like 403bs and the Federal Thrift Savings Plan). If an employee separates from service (voluntarily or involuntarily) during or after the calendar year they turn 55, they can withdraw from *that specific 401k* without incurring the 10% early distribution penalty. Key conditions apply: it only covers the plan the employee participated in when turning 55 or older, and the funds must remain in that employer's plan; rolling them into an IRA or a new employer's plan forfeits this benefit. Old 401ks can be rolled into the current employer's plan before separation to consolidate funds under this rule. An enhanced version exists for some qualified public safety employees, allowing penalty-free distributions at age 50 or after 25 years of service, whichever is earlier. It's crucial to remember that while the Rule of 55 waives the penalty, applicable income taxes on withdrawals still apply. Brokamp concluded by reiterating the importance of understanding these features and advocating for their inclusion in one's workplace retirement plan.