Workers who retire with a large block of employer shares locked inside a 401(k) face a tax decision that can shift tens of thousands of dollars between ordinary-income rates and the lower capital-gains rate. Federal law carves out a specific election, called net unrealized appreciation, that lets those shares leave the plan with only the original cost basis taxed as ordinary income. The gain built up while the stock sat in the plan is excluded from gross income at distribution and later taxed as a capital gain when the shares are sold. With the top ordinary-income bracket at 37 percent and the top long-term capital-gains rate at 20 percent, the spread between those two rates makes NUA one of the most consequential choices a departing employee can make.
How the NUA election works under Section 402
The statutory authority sits in Section 402(e)(4) of the Internal Revenue Code, which governs the taxability of a beneficiary of an employees’ trust. Under that provision, a participant who takes a lump-sum distribution that includes employer securities can exclude the NUA portion from gross income at the time of distribution. Only the plan’s cost basis in the shares is treated as ordinary income. The remaining appreciation sits untaxed until the participant sells the stock, at which point it is treated as capital gain.
Treasury regulations flesh out the mechanics. The regulation at 26 CFR Section 1.402(a)-1 defines how NUA is computed: the fair market value of the securities at distribution minus the plan’s cost basis. That same regulation specifies that the NUA amount is not included in basis at distribution and becomes capital gain when realized in a later taxable transaction. A separate regulation, Section 1.402A-1, confirms the same capital-gain outcome applies to employer securities held inside designated Roth accounts, cross-referencing Section 402(e)(4)(B) directly.
The IRS retained these rules when it finalized regulations described in Internal Revenue Bulletin 2007-22. That bulletin’s preamble confirmed the agency’s decision to keep the existing treatment for distributions of employer securities, preserving the NUA election without material changes. For reporting purposes, plan custodians use IRS Form 1099-R, which includes a dedicated Box 6 for the NUA amount so the election can be tracked on the recipient’s tax return.
Why the 2007 regulatory freeze left an education gap
Treasury’s decision to leave the NUA rules intact after 2007 removed any regulatory uncertainty about whether the break would survive. That stability, however, did not translate into widespread awareness among plan participants. No publicly available IRS Statistics of Income tables or SOI Bulletin releases quantify how many lump-sum distributions actually claim the Section 402(e)(4) election or the total dollars of NUA deferred across the tax-filing population. Without that data, it is impossible to confirm whether plans whose sponsors added NUA-education materials after the 2007 regulations saw a measurable rise in lump-sum stock distributions relative to plans that did not. The hypothesis is plausible on its face, because awareness of a tax break typically drives uptake, but the federal data needed to test it does not appear to exist in published form.
In practice, the education gap shows up in two places. First, many plan participants never learn that NUA is available until after they have already rolled employer stock into an IRA, at which point the election is lost. Second, even those who have heard of the concept often misunderstand the all-or-nothing nature of the lump-sum requirement and the need to distribute the entire plan balance in one tax year. Missteps on either point can convert what might have been capital gain into fully taxable ordinary income.
When NUA tends to help-and when it does not
Because NUA shifts appreciation from ordinary income to capital gain, it is most attractive when employer stock has a low cost basis and the participant expects to be in a relatively high ordinary-income bracket in retirement. A long-tenured employee who accumulated company shares through matching contributions, with decades of growth inside the plan, is the classic candidate. By contrast, if the stock has only modest appreciation, or if the retiree expects to rely heavily on standard deductions and lower brackets, the benefit narrows and may not justify the loss of tax-deferred status on the distributed shares.
Concentration risk also matters. Electing NUA means holding employer stock in a taxable account, where the participant bears market risk without the diversification rules that often apply inside qualified plans. In some cases, selling immediately after distribution and recognizing capital gain can still be preferable to keeping a concentrated position inside the plan and eventually paying ordinary income on the same growth. The analysis is highly fact-specific, which is why individualized tax advice is critical.
Where participants and advisors can find guidance
Because the Internal Revenue Code and regulations are dense, most retirees rely on professionals to navigate the NUA rules. The IRS maintains an online directory of credentialed preparers and firms through its tax professional search, which can help participants locate practitioners familiar with retirement-distribution planning. For questions about how a specific 401(k) or stock bonus plan will process a lump-sum distribution, participants can also contact the plan administrator and, if necessary, seek clarification from the IRS using its online account tools and published guidance.
Ultimately, the NUA election is not a loophole created by aggressive planning but a long-standing feature of the tax code. Its value depends on timing, market performance, and personal tax circumstances. Without better aggregate data, policymakers and researchers cannot say how often it is used or by whom. For individual workers approaching retirement with significant employer stock, however, understanding Section 402(e)(4) before funds leave the plan can mean the difference between an avoidable tax bill and a more efficient, legally sanctioned path to accessing long-accumulated savings.
