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IRC 1371: S-Corp Accumulated Earnings and Profits from Prior C-Corp Years

Last reviewed: July 2026  |  Americas Tax Practitioner Series

What IRC 1371 Does: Subchapter C Carries Over into the S Period

When a corporation makes an S election, it does not wipe the slate clean. IRC 1371 is the provision that governs how Subchapter C rules interact with the S period, and its most consequential message is this: accumulated earnings and profits earned during C-corp years survive the S election intact and remain on the books until the corporation actively distributes or purges them.

For practitioners advising clients that converted from C-corp status -- or acquired a business with C-corp history -- this is the central risk point. An S-corp with accumulated earnings and profits (AEP) from prior C-corp years faces a different distribution ordering, a potential corporate-level penalty tax on passive income, and the threat of automatic S election termination if the passive income problem persists long enough. None of those consequences exist for an S-corp with zero AEP.

This guide walks through the statutory mechanics of IRC 1371 S-corp accumulated earnings and profits: how AEP is measured and carried over, how it interacts with the IRC 1368 distribution ordering stack, when it triggers the IRC 1375 passive income penalty, and what practitioners can do to manage or eliminate it.

AEP Defined and Measured

Accumulated earnings and profits is a Subchapter C concept. It measures the cumulative undistributed, previously taxed earnings of a C-corporation, adjusted under the rules of Subchapter C (primarily IRC 312). AEP is not book retained earnings and it is not taxable income; it is a separate tax accounting concept that tracks the pool of economic value a C-corporation has generated and retained, minus amounts that have been distributed as dividends and minus certain adjustments for timing differences.

The most important distinction for S-corp practitioners is the difference between AEP and the accumulated adjustments account (AAA). They track different things:

Because AEP and AAA track different things and change under different rules, a profitable S-corp can build a large AAA over many years while its AEP from C-corp years sits untouched -- creating or perpetuating IRC 1375 exposure that the practitioner may not have noticed.

Common sources of AEP in a C-to-S conversion context include: retained earnings accumulated before the S election, E&P inherited through a corporate acquisition or reorganization during C-corp years, and E&P picked up through a merger with another C-corp. AEP does not include tax-exempt income that was never taxed at the C-corp level, and it is reduced by dividends paid during the C-corp years.

IRC 1371(a): The General Rule -- Subchapter C Does Not Apply

The general rule of IRC 1371(a) is that Subchapter C does not apply to an S-corporation during the S period, "except as otherwise provided." That exception phrase does significant work. It is the opening through which AEP, the IRC 1374 built-in gains tax, and certain other C-corp provisions reach into the S period.

For day-to-day S-corp compliance, the general non-applicability of Subchapter C means that an S-corp does not compute corporate-level income tax the way a C-corp does, does not use the dividends-received deduction, and does not accumulate E&P from its S-period operations. But the "except as otherwise provided" exception means the practitioner cannot simply ignore C-corp mechanics on conversion. The provisions that survive -- most importantly IRC 1371(c) on AEP carryover -- require active tracking throughout the life of the S-corp.

IRC 1371(c): Accumulated E&P Carryover into the S Period

IRC 1371(c) is the operative provision that carries AEP from the C period into the S period. Its core mechanics are:

  1. Opening AEP is fixed at the date of the S election. The corporation's AEP at the close of the last taxable year as a C-corp (or as of the effective date of the S election, if mid-year) becomes the opening AEP balance for the S period. That figure does not change simply because the corporation elected S status.
  2. S-corp income and loss do not touch AEP. Under IRC 1371(c)(1), the S-corp's income, gain, loss, and deduction recognized during the S period do not increase or decrease AEP. All of that activity flows through AAA. AEP is frozen from the S-corp's operational standpoint.
  3. AEP decreases only through distributions from the AEP tier. Under IRC 1368(c)(2), when a distribution exceeds the AAA balance and the corporation has AEP, the excess is treated as a dividend out of AEP, which reduces AEP dollar for dollar. AEP can also decrease through the bypass election, described below, which causes distributions to come from AEP before AAA.
  4. AEP does not appear prominently on Form 1120-S. The Unappropriated Retained Earnings column on Schedule M-2 is intended to track AEP, but it is not a formal E&P computation and can diverge from the true AEP balance if the underlying C-corp workpapers were not carried forward accurately. Practitioners must maintain a separate AEP workpaper, anchored to the final C-corp return, and update it annually for distributions from the AEP tier.
Practitioner note: AEP computation at conversion AEP from C-corp years does not include amounts attributable to income that was exempt from tax (such as tax-exempt bond interest) or amounts that were previously distributed as a dividend during the C-corp years. Practitioners computing AEP at the date of the S election should start from the C-corporation's most recent tax return E&P schedule and adjust for any interim distributions made after that return date but before the S election becomes effective.

Interaction with IRC 1368: The Distribution Ordering Stack

Understanding AEP in isolation is not enough. The practical impact of AEP on a shareholder's tax liability depends on where AEP falls in the IRC 1368 distribution ordering. For an S-corp with AEP from C-corp years, distributions are ordered under IRC 1368(c) as follows:

  1. Tier 1: Accumulated Adjustments Account (AAA). The first dollars of a distribution are sourced from AAA and are tax-free to the shareholder to the extent of their stock basis. A distribution from AAA reduces the shareholder's stock basis dollar for dollar. Distributions do not reduce AAA below zero.
  2. Tier 2: Accumulated Earnings and Profits (AEP). Once AAA is exhausted (or under a bypass election), distributions come from AEP and are treated as dividends under IRC 1368(c)(2). AEP-layer distributions are taxable to the shareholder as qualified dividends at the preferential rates under IRC 1(h) (verify current applicable rates at IRS.gov). The corporation's AEP is reduced by the amount distributed from this tier.
  3. Tier 3: Other Adjustments Account (OAA). After AEP is exhausted, distributions come from OAA, which tracks tax-exempt income and related non-deductible expenses. OAA distributions are tax-free to the extent of stock basis; any excess is capital gain.
  4. Tier 4: Remaining stock basis, then capital gain. Once all three accounts are exhausted, distributions reduce remaining stock basis until basis reaches zero, at which point the excess is capital gain.

The AEP tier is the "stuck" layer in this stack. Under default ordering, a profitable S-corp that consistently generates AAA will distribute from AAA year after year and never touch AEP -- leaving the AEP balance from C-corp years in place indefinitely. That untouched AEP balance is the condition that keeps the corporation exposed to the IRC 1375 passive income penalty for as long as it holds any passive investment income.

Practitioner note: AEP persistence over time S-corp income and loss during the S period do not adjust AEP; only distributions from the AEP tier (under IRC 1368(c)(2)) reduce AEP. This asymmetry means AEP can persist for decades in an S-corp that consistently distributes from the AAA tier rather than making bypass elections. A client who converted from C-corp to S-corp 15 years ago may still carry the same AEP balance from the conversion date if no one has actively tracked or reduced it.

The IRC 1375 Passive Income Penalty: Why AEP Is the On/Off Switch

IRC 1375 imposes a corporate-level tax on an S-corporation's excess net passive income (ENPI) when two conditions are both present: (1) the corporation has AEP from C-corp years, and (2) passive investment income for the taxable year exceeds 25% of gross receipts. If either condition is absent, the tax does not apply. This is the most important planning consequence of AEP for long-lived S-corps.

Passive investment income for this purpose includes dividends, interest, rents, royalties, annuities, and gains from the sale or exchange of stock and securities -- the same categories defined in IRC 1362(d)(3)(C). An S-corp that holds investment assets, receives rental income, or has significant interest income is the most common candidate for IRC 1375 exposure.

The penalty tax is computed on "excess net passive income," which is the net passive income multiplied by the fraction: (passive investment income less 25% of gross receipts) divided by passive investment income. The statutory rate is 21% (verify current rate at IRS.gov, as rate changes may apply). The tax is imposed at the entity level -- separate from and in addition to the pass-through tax the shareholders pay on their pro-rata share of S-corp income.

The critical planning point is the on/off nature of the AEP condition. An S-corp with zero AEP cannot trigger IRC 1375, period -- regardless of how much passive income it earns. An S-corp with even a nominal AEP balance is exposed if passive income crosses the 25% threshold. This binary structure gives practitioners a clear objective: if the corporation has passive income, eliminate AEP.

The Bypass Election Under IRC 1368(e)(3)

The bypass election is a once-per-year tool that allows the corporation to reverse the default distribution ordering for a taxable year. Under the default ordering, distributions come from AAA before AEP. With the bypass election in effect, distributions come from AEP before AAA. This allows the corporation to draw down its AEP balance while leaving AAA intact.

The election requires the consent of all shareholders who receive a distribution during the year. It is made on the corporation's Form 1120-S for the relevant tax year. The election is annual -- it does not carry forward automatically, and the corporation must affirmatively elect it each year if it wants to continue distributing from AEP first.

The shareholder-level consequence of the bypass election is that AEP-layer distributions are taxable as qualified dividends at the IRC 1(h) preferential rates (verify current applicable rates at IRS.gov). For shareholders who are in a lower bracket or who have significant qualified dividend room, this may be a favorable trade compared to the alternative: continued IRC 1375 corporate-level penalty taxes in future years when passive income is high.

The bypass election is most commonly recommended when:

AEP Purging Strategies

Eliminating AEP removes the precondition for both the IRC 1375 penalty tax and the IRC 1362(d)(3) automatic termination threat (described below). There are three primary mechanisms:

Cash Dividend Distributions from the AEP Tier

The most direct method is to distribute cash from the AEP tier using the bypass election. The corporation makes the bypass election on its timely filed Form 1120-S, distributions in that year are sourced from AEP to the extent of the AEP balance, and AEP decreases dollar for dollar. The shareholders recognize qualified dividend income. In subsequent years, if AEP has been fully eliminated, the bypass election is no longer needed and the corporation reverts to the simpler IRC 1368(b) distribution ordering.

The Bypass Election as a Multi-Year Strategy

Where the AEP balance is large relative to distributable cash, the bypass election can be used over multiple years to systematically draw down AEP. Each year, the corporation makes the bypass election and distributes cash from AEP in a controlled amount. The practitioner should model the timeline to full AEP elimination against the projected passive income ratio to ensure the elimination plan outpaces the IRC 1375 and IRC 1362(d)(3) risks.

Redemptions

A redemption that does not qualify as a sale or exchange under IRC 302(b) is treated as a distribution under IRC 301 and reduces AEP in the ordinary course. However, practitioners should not structure redemptions primarily to purge AEP without analyzing the IRC 302 treatment; an inadvertent sale-or-exchange classification eliminates the AEP-reduction effect. Redemptions are a secondary AEP-purging tool, not the primary one.

Practitioner note: AEP elimination as S-election preservation When an S-corp with AEP has passive investment income (dividends, interest, rents, royalties, annuities, and gains from stock and securities) exceeding 25% of gross receipts in three consecutive years, the S election is automatically terminated under IRC 1362(d)(3) -- independent of the IRC 1375 penalty tax. This is a harder consequence than the penalty tax: the corporation involuntarily returns to C-corp status. Practitioners should treat AEP elimination as an S-election preservation strategy, not just a tax minimization exercise. The three-year clock starts from the first year the passive income ratio is exceeded, and it resets only if the ratio drops below 25% or if AEP reaches zero.
Practitioner workflow: Managing AEP from conversion through ongoing S-corp years (1) On converting a C-corp to an S-corp, pull the final C-corp return E&P schedule and compute opening AEP; memorialize it in a workpaper retained indefinitely. (2) Track AEP annually in a dedicated workpaper outside of Schedule M-2; do not rely on the Unappropriated Retained Earnings column alone. (3) Model the IRC 1375 passive income ratio each year before the return filing deadline. (4) Decide annually whether to make the bypass election; if the answer is yes, make the election on the timely filed Form 1120-S. (5) Advise the client to purge AEP through planned distributions before passive income ratios become problematic, using a multi-year plan if the AEP balance is large.

OBBBA Considerations

The One Big Beautiful Bill Act (OBBBA) contains provisions that may affect AEP computation, S-corp distribution planning, and passive income calculations. Key areas to verify include: changes to bonus depreciation timing that affect the flow of deductions through AAA (and therefore the AAA balance available before the AEP tier is reached in each distribution year); modifications to the research expenditure capitalization rules under IRC 174 that affect timing of deductions; and any LIFO recapture provisions applicable to C-to-S conversions that affect the level of AEP at conversion.

All OBBBA provisions should be verified against current IRS.gov guidance and the final enacted text, as the legislation was subject to amendment and implementation rulemaking at the time of this writing. Do not rely on pre-enactment summaries or conference report descriptions for filing positions; confirm the operative statutory text and any issued regulations or IRS notices.

AEP Scenario Comparison: Key Fact Patterns

The table below compares ten fact patterns that practitioners commonly encounter when advising S-corps with C-corp history. Use it as a quick diagnostic to identify where AEP issues require active planning.

Scenario AEP Present? IRC 1375 Exposure? IRC 1368 Ordering Recommended Action
S-corp formed as S from inception; no C-corp history No None IRC 1368(b): basis then capital gain Confirm no predecessor C-corp AEP; file under 1368(b) ordering
C-to-S conversion; C-corp had zero E&P at conversion No None IRC 1368(b): basis then capital gain Document zero E&P with final C-corp return; confirm annually
C-to-S conversion; C-corp had positive AEP; corporation is an active operating business with minimal passive income Yes Low (passive income well below 25% of gross receipts) IRC 1368(c): AAA, then AEP, then OAA Track AEP; monitor passive income ratio annually; no immediate bypass election needed
S-corp with AEP; passive investment income below 25% of gross receipts Yes Threshold not met; no penalty in current year IRC 1368(c): AAA first under default Monitor passive ratio closely; model risk if passive income grows; consider proactive AEP reduction
S-corp with AEP; passive investment income exceeds 25% of gross receipts (IRC 1375 triggered) Yes Active; penalty tax applies at 21% (verify at IRS.gov) on ENPI IRC 1368(c): AAA first; AEP tier reached on excess distributions Model bypass election to begin AEP reduction; compute ENPI and report IRC 1375 tax; accelerate AEP purging plan
S-corp with AEP making bypass election under IRC 1368(e)(3) Yes, reducing Reduced as AEP decreases; watch 25% ratio AEP distributed first; AAA preserved Ensure all shareholders consent; make election on timely filed Form 1120-S; issue Form 1099-DIV for AEP-layer distributions
S-corp successfully eliminates AEP entirely in year one through large bypass election distribution No (post-purge) None after AEP reaches zero Reverts to IRC 1368(b) ordering once AEP is gone Document AEP zero balance in workpaper; confirm reversion to 1368(b); no further bypass election needed
S-corp converted from a C-corp that acquired AEP through a subsidiary liquidation under IRC 332 Yes (includes subsidiary E&P under IRC 381) Yes, if passive income threshold met IRC 1368(c): full AEP pool (including inherited subsidiary E&P) in ordering stack Reconstruct E&P through IRC 381 carryover; include in opening AEP workpaper at conversion; purge through bypass elections
S-corp whose election was terminated (C-corp period) and then re-elected; AEP from original C-corp years plus C-period accumulation Yes (both original and C-period AEP) Yes, if passive income threshold met IRC 1368(c): combined AEP pool from all C-corp periods Reconstruct AEP through each period (original C, first S, intervening C, second S); maintain continuous workpaper chain
Multi-state S-corp with differing state E&P definitions; federal AEP positive but state conformity varies Yes (federal); state treatment varies Federal IRC 1375 exposure based on federal AEP; state-level consequences vary Federal IRC 1368(c) ordering governs for federal; state may or may not conform Compute federal AEP under IRC rules; separately analyze each state's E&P conformity; consult state-specific guidance

Frequently Asked Questions: IRC 1371 S-Corp AEP

Does an S-corp that was always an S-corp (never a C-corp) have AEP?

No. An S-corporation that has been an S-corp since inception and has never been a C-corporation has no accumulated earnings and profits (AEP). AEP is a Subchapter C concept that measures the undistributed, previously taxed earnings of a C-corporation. Because a pure S-corp was never subject to Subchapter C tax on its earnings, it has no pool of AEP to carry. Such a corporation distributes under IRC 1368(b) -- the simpler two-tier regime -- rather than the AEP-sensitive three-tier regime of IRC 1368(c). Confirming the absence of AEP before applying the simpler ordering is itself an important compliance step; it requires reviewing any predecessor entity history, including mergers, acquisitions, and reorganizations.

How is AEP measured at the date a C-corp converts to an S-corp?

AEP at the date of the S election is measured under Subchapter C principles using the C-corporation's accumulated earnings and profits as of the close of the last taxable year as a C-corp. In practice, practitioners start with the E&P balance shown on the corporation's most recent C-corp return (Form 1120, Schedule M-2 or the equivalent E&P workpaper), then adjust for: (1) any dividends distributed during the final C-corp year that have not yet been reflected; (2) any tax-exempt income items that inflate book E&P but were never taxed and therefore may not belong in AEP; and (3) timing differences between book and tax E&P from prior years. The resulting figure is the opening AEP balance that carries into the S period. This computation should be memorialized in a formal workpaper and retained indefinitely, because AEP does not appear with precision on Form 1120-S Schedule M-2 and the underlying C-corp returns may eventually be unavailable.

Does S-corp net income or loss affect AEP during the S period?

No. S-corp income, gain, loss, and deduction during the S period do not adjust AEP. AEP is frozen at the amount inherited from the C-corp years and changes only when distributions reach the AEP layer under IRC 1368(c)(2), reducing AEP by the amount distributed from that tier. This asymmetry is the central mechanical point of IRC 1371(c): S-corp operations flow through AAA, not AEP. A profitable S-corp can operate for decades, growing its AAA substantially, while the AEP balance from its C-corp years remains static -- unless the corporation actively distributes from or purges the AEP tier.

What is the IRC 1375 passive income penalty tax rate, and when does it apply?

The IRC 1375 passive income tax is imposed at the corporate level on an S-corporation's excess net passive income (ENPI). It applies only when the corporation has accumulated earnings and profits (AEP) from C-corp years and when passive investment income exceeds 25% of gross receipts for the taxable year. The statutory rate is 21% (verify current rate at IRS.gov, as rate changes may apply). ENPI is the portion of net passive income attributable to the excess of passive investment income over 25% of gross receipts, computed under the formula in IRC 1375(b). The tax is in addition to, not a substitute for, the shareholder-level pass-through tax on S-corp income. If AEP is zero, IRC 1375 cannot apply regardless of how much passive income the corporation earns.

Can an S-corp eliminate AEP through a stock redemption rather than a cash dividend?

Generally, no -- at least not directly. A stock redemption reduces AEP (as a distribution under IRC 301) only if it does not qualify as a sale or exchange under IRC 302(b). If the redemption qualifies as a sale or exchange (meeting one of the IRC 302(b) tests: substantially disproportionate, complete termination, or not essentially equivalent to a dividend), it is treated as a capital transaction at the shareholder level and does not reduce the corporation's AEP in the ordinary distribution sense. Practitioners should not plan redemptions primarily as AEP-purging vehicles without first confirming the IRC 302 treatment, because a mischaracterized redemption can produce an unexpected dividend to the redeeming shareholder rather than capital gain, while failing to reduce AEP as intended.

What happens to AEP if the S-corp election is terminated and then re-made?

When an S-corp election terminates, the corporation returns to C-corp status. During the C-corp period, the entity again accumulates (or reduces) earnings and profits under Subchapter C rules. When the corporation subsequently makes a new S election, AEP at the start of the new S period equals the AEP at the end of the prior S period (unchanged by S-period operations), adjusted for any C-period activity between the termination and re-election. Importantly, new C-corp losses accrued during the intervening C period can reduce AEP before the re-election takes effect. Practitioners advising clients with a termination-and-re-election history must reconstruct the AEP account through each period rather than relying solely on the most recent Form 1120-S Schedule M-2.

If the S-corp makes the bypass election under IRC 1368(e)(3), does that mean all distributions that year come from AEP first?

Yes, but only to the extent AEP exists. Under IRC 1368(e)(3), with the consent of all shareholders, the corporation may elect to treat distributions as coming from AEP before AAA. The election is all-or-nothing for the tax year in which it is made: once in effect, distributions run through AEP (to the extent AEP exists) before any amount is treated as coming from AAA. The election does not carry forward to subsequent years; a new election must be made each year the corporation wishes to continue bypassing AAA. The practical effect is that AEP distributions create qualified dividend income for shareholders in the year of the election, rather than tax-free AAA distributions. This is intentional: the goal is typically to zero out AEP and thereby eliminate future IRC 1375 exposure.

How does an S-corp with AEP report distributions on Schedule M-2 of Form 1120-S?

Schedule M-2 of Form 1120-S tracks three accounts in separate columns: AAA, OAA, and Unappropriated Retained Earnings (which reflects the AEP from C-corp years). Distributions reduce each column in the IRC 1368(c) ordering sequence. Under the default ordering, distributions reduce AAA first; once AAA reaches zero, the AEP column is reduced for the portion of distributions treated as coming from the AEP tier. The key compliance risk is that Form 1120-S does not require a formal E&P schedule comparable to the C-corp Form 1120 Schedule M-2; the AEP column on the S-corp Schedule M-2 may not reconcile accurately to the true AEP balance if the practitioner has not maintained a separate workpaper. Any AEP-tier distribution must be reported to shareholders on Form 1099-DIV as a qualified dividend; failure to issue Form 1099-DIV is a reportable compliance error.

Have an S-Corp Client with C-Corp History?

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