South Carolina Bonus Depreciation: Decoupled From §168(k).
South Carolina does not allow federal §168(k) bonus depreciation. S.C. Code §12-6-50 lists §168(k) among the Internal Revenue Code sections "specifically not adopted by this State" — naming it as bonus depreciation in the same clause — for both individuals and businesses. The federal deduction is unaffected; the South Carolina return simply doesn't mirror it.
Reviewed by Cost Seg Smart Editorial Team · Last verified against S.C. Code §12-6-50 — IRC sections specifically not adopted
The 30-second answer: South Carolina does not allow federal §168(k) bonus depreciation. S.C. Code §12-6-50 specifically lists §168(k) — along with §168(l), (m), and (n) — among the Internal Revenue Code sections "not adopted by this State," and says so for both individual and business taxpayers.
What that means in practice: the full federal Year-1 bonus is claimed on the federal return exactly as it would be anywhere else. On the South Carolina return, the reclassified components are instead depreciated under ordinary MACRS from year one — no Year-1 acceleration, and no later-year subtraction to make up for it, because nothing was deferred.
On a representative South Carolina single-family rental (the single-family rental band we publish, 9–32% of depreciable basis reclassified, 16% representative), the reclassified components alone generate an estimated $18K–$165K of federal Year-1 depreciation. At the 37% federal top bracket, that is roughly $6,660–$61,570 of federal Year-1 tax savings — a South Carolina-level figure would spread that same reclassified amount across the ordinary MACRS schedule instead of taking it in year one.
Federal vs South Carolina, Side by Side
For an individual investor's or South Carolina business's cost-segregation-reclassified components:
| Tax provision | Federal (IRC) | South Carolina |
|---|---|---|
| Bonus depreciation under §168(k) | 100% may apply to qualified property acquired and placed in service after January 19, 2025, subject to §168(k) eligibility, related-party/prior-use, binding-contract, and election rules | Not adopted. §12-6-50 specifically excludes §168(k) — and §168(l), (m), (n) — from South Carolina's Internal Revenue Code adoption |
| Applies to individuals and businesses | Not applicable | Both. The non-adoption applies "for purposes of this title and all other titles that provide for taxes administered by the department" |
| Recovery of the reclassified basis | Fully deducted in Year 1, if bonus-eligible | Recovered over the property's ordinary MACRS life from year one; no Year-1 bonus, no later subtraction |
| IRC conformity method | Not applicable | Fixed conformity date (amended through December 31, 2024 per §12-6-40, updated annually by act) — not a rolling-conformity state |
| Federal usability of the deduction | Subject to passive activity, at-risk, basis, and business-interest limits | Same federal limits govern the federal deduction; South Carolina's non-adoption applies independently |
| MACRS asset class lives | 5 / 7 / 15 / 27.5 / 39 yr per Rev. Proc. 87-56 | Same class lives; South Carolina depreciation is computed against them without the §168(k) allowance |
Source: S.C. Code §12-6-50 and §12-6-40; IRC §168(k). Federal bonus figures reflect current law; eligibility depends on acquisition and placed-in-service dates and elections.
What §12-6-50 actually says, and why it matters
S.C. Code §12-6-50 lists a set of Internal Revenue Code sections that are "specifically not adopted by this State." Federal bonus depreciation under §168(k) is named directly on that list, alongside the related §168(l), (m), and (n) provisions. This is not an inference from a general conformity date — the statute names the section.
The non-adoption clause is also written broadly: it applies "for purposes of this title and all other titles that provide for taxes administered by the department," which is why it reaches both individual and business taxpayers rather than one taxpayer class alone.
Separately, South Carolina adopts the Internal Revenue Code as of a fixed date under §12-6-40 — currently amended through December 31, 2024, and updated only when the legislature acts, rather than rolling forward automatically each year. That is a second, independent reason South Carolina would not simply follow a future federal change to bonus depreciation without its own legislative action — on top of §12-6-50's direct exclusion of §168(k) today.
Practically: depreciation for South Carolina purposes is computed under §168 without the §168(k) additional allowance. A component that would be fully deducted in Year 1 on the federal return instead recovers over its ordinary MACRS class life — 5, 7, 15, 27.5, or 39 years — on the South Carolina return, starting from year one rather than being deferred and returned on a schedule.
Illustrative numbers: a South Carolina single-family rental
Using the single-family residential (SFR) band we publish — 9–32% of depreciable basis reclassified into 5/7/15-year property, 16% representative — on a property priced between $250,000 and $650,000, with a 20% residential land allocation, and 100% federal bonus depreciation for eligible components under current law:
| Line item | Federal | South Carolina |
|---|---|---|
| Purchase price band | $250,000–$650,000 | Same property |
| Depreciable basis (20% land allocation) | $200,000–$520,000 | Same basis; no §168(k) allowance computed |
| Reclassified to 5/7/15-yr (9–32% of basis) | $18K–$165K | Recovered over ordinary MACRS life instead |
| Year-1 treatment | $18K–$165K deducted (100% bonus, if eligible) | Ordinary MACRS Year-1 depreciation only (no §168(k) allowance) |
| Later-year treatment | Not applicable (already deducted) | Reclassified basis continues recovering over its remaining ordinary MACRS life |
| Marginal tax rate | Up to 37% | South Carolina individual income tax rate (verify current year with the SC Dept. of Revenue) |
| Illustrative Year-1 federal tax savings on reclassified components | ~$6,660–$61,570 (37% × $18K–$165K) | Same dollars recovered on the ordinary MACRS schedule, not accelerated to Year 1 |
Figures are illustrative and use the site's published SFR reclassification band; your result depends on your basis, land allocation, bracket, component mix, and eligibility. Whether the full federal deduction is usable in the current year still depends on your passive-loss, at-risk, basis, and business-interest situation. The South Carolina column reflects the state's non-adoption of §168(k) under current law; confirm current-year South Carolina depreciation mechanics and rates with your CPA.
See a sample cost segregation report
Look at exactly what your South Carolina study delivers: the component-by-component 5/7/15-year schedule, the Form 4562-ready numbers, and the documentation your CPA files. Real reports are our best answer to "is this legit?"
Forms your CPA files for a South Carolina property
For a South Carolina investor or business, the workflow runs on both the federal return and the South Carolina return, because the two depreciation figures diverge from year one:
- Federal Form 4562: depreciation and amortization, including the §168(k) bonus deduction on eligible reclassified components. Flows to Schedule E (rental) or Schedule C (active business), or the applicable corporate return.
- Schedule E (or Schedule C): the accelerated federal deduction reduces federal taxable income in Year 1, subject to the federal passive-loss, at-risk, basis, and business-interest limits.
- South Carolina income tax return: depreciation is computed under §168 without the §168(k) additional allowance, per S.C. Code §12-6-50, so the South Carolina depreciation figure for reclassified components differs from the federal figure starting in year one.
- Ordinary MACRS recovery in later years: South Carolina continues recovering the reclassified basis over its remaining ordinary 5, 7, or 15-year life, since no bonus allowance was taken for state purposes at any point.
- Form 3115 §481(a) section: included only if this is a federal lookback method change on a property placed in service in a prior year (see below).
The reclassified schedule is the same engineered output for both books; what differs is that South Carolina never applies the §168(k) allowance to it, on either a current-year study or a prior-year Form 3115 catch-up.
Form 3115 lookback on a South Carolina property
If the property was placed in service in a prior tax year and depreciation was reported using a non-segregated method, a federal Form 3115 (Application for Change in Accounting Method) may allow a current-year §481(a) catch-up adjustment for the accelerated depreciation you missed, generally without amending prior returns. This is often the single biggest acceleration mechanism in cost segregation. Any catch-up dollars are illustrative and depend on placed-in-service date, prior depreciation claimed, bonus eligibility, land allocation, and component mix.
The federal §481(a) catch-up is the primary lever, subject to the federal passive-loss, at-risk, and basis limits. For South Carolina, the §168(k)-attributable portion of that federal catch-up is not mirrored on the state return, for the same reason a current-year study isn't: §12-6-50 excludes §168(k) regardless of whether the bonus arises from a current acquisition or a prior-year method change caught up through Form 3115.
See our full Form 3115 cost segregation guide for federal mechanics, partnership and LLC pass-through treatment, and timing rules.
Should you still do cost segregation in South Carolina?
Yes, for the federal reasons — South Carolina's non-adoption of §168(k) does not change the federal benefit at all. Go in with a clear picture of what changes at the state level:
- The full federal Year-1 bonus is intact. South Carolina's non-adoption applies only to the South Carolina return; the federal §168(k) deduction is claimed in full on the federal return. How much you use in the current year still depends on your passive-loss, at-risk, basis, and business-interest situation.
- The South Carolina deduction is not accelerated, but it is not lost. The reclassified basis recovers over its ordinary MACRS life on the state return — the same 5, 7, or 15-year schedule the components would use without bonus depreciation. Cost segregation's shorter class lives (versus a 27.5 or 39-year default) still apply on the South Carolina return; only the §168(k) first-year acceleration does not.
- Confirm current-year rates and forms with your CPA. South Carolina's fixed conformity date is updated annually by the legislature, so verify the current tax year's conformity language before filing, even though the §168(k) exclusion itself is a stable, named provision.
The nuance to flag with your CPA is precise, not vague: the federal deduction is real and unaffected, the South Carolina deduction for the same reclassified components exists but is spread over the ordinary MACRS schedule rather than taken in Year 1, and neither fact should be blended into the other when you're estimating your total benefit.
Frequently asked
Does South Carolina allow bonus depreciation?
No. South Carolina is decoupled from federal §168(k) bonus depreciation. S.C. Code §12-6-50 lists §168(k) among the Internal Revenue Code sections "specifically not adopted by this State," and names it as bonus depreciation in the same clause. An individual investor or a South Carolina business still claims the full federal Year-1 bonus on the federal return (100% may apply to qualified property acquired and placed in service after January 19, 2025, subject to §168(k) eligibility, related-party/prior-use, binding-contract, and election rules), but that bonus is not available on the South Carolina return. South Carolina depreciation is computed under §168 without the bonus allowance and recovers over the property's ordinary MACRS life instead.
Is this an add-back, or does South Carolina never allow the deduction at all?
South Carolina never grants the deduction in the first place, which is a different mechanic from an add-back-and-return state. Some decoupled states (Minnesota, Connecticut) let a taxpayer take a partial bonus deduction and then add back the rest, recovering it later through scheduled subtractions. South Carolina isn't that: §12-6-50 specifically excludes §168(k) from the state's adopted Internal Revenue Code, so the bonus allowance is never computed for South Carolina purposes at all. There is no later-year subtraction to look forward to, because nothing was deferred — the property simply depreciates under ordinary MACRS on the South Carolina return from year one.
Does South Carolina's non-adoption apply to individuals, businesses, or both?
Both. §12-6-50 states that the non-adopted Internal Revenue Code sections, including §168(k), do not apply "for purposes of this title and all other titles that provide for taxes administered by the department" — language that is not limited to one taxpayer class. An individual investor filing a South Carolina personal income tax return and a South Carolina corporation both compute depreciation without the federal bonus allowance.
Is South Carolina a rolling-conformity state that might pick up bonus depreciation automatically?
No, and this is a separate fact from the non-adoption above, not the same one restated. South Carolina uses a FIXED IRC conformity date under §12-6-40 — currently amended through December 31, 2024, updated annually by the legislature rather than rolling forward automatically. Even setting the §12-6-50 exclusion aside, South Carolina would not automatically adopt a federal change through rolling conformity; the legislature would need to act. Combined with §12-6-50's specific carve-out of §168(k), South Carolina's non-conformity to bonus depreciation is not a temporary lag waiting to catch up — it is a deliberate, named exclusion.
Is cost segregation still worth it if I own property in South Carolina?
Yes, for the federal deduction — which is unaffected by South Carolina's position and is usually the dominant driver of the benefit. The honest South Carolina-specific point is that the state-level Year-1 acceleration doesn't exist: your South Carolina depreciation deduction for reclassified components is computed under ordinary MACRS from year one, not accelerated the way the federal deduction is. The study still reclassifies your components into shorter federal recovery periods, which is what drives the federal Year-1 benefit; South Carolina simply doesn't mirror that timing. Whether the full federal deduction is usable in the current year also still depends on federal passive-activity, at-risk, basis, and business-interest limits.
Can I use Form 3115 on a South Carolina property I bought years ago?
Often, yes, at the federal level. If the property was placed in service in a prior tax year and depreciation was reported using a non-segregated method, a federal Form 3115 (Application for Change in Accounting Method) may allow a current-year §481(a) catch-up for the accelerated depreciation you missed, generally without amending prior returns. For South Carolina, the same non-adoption applies to the catch-up as to a current-year study: the §168(k)-attributable portion of the federal catch-up is not mirrored on the South Carolina return, and the reclassified basis instead follows ordinary MACRS recovery for state purposes.
What does a South Carolina cost segregation study rely on for its numbers?
The study reclassifies building components into IRS-recognized MACRS class lives (5, 7, and 15-year) per Rev. Proc. 87-56, using an engineering-based methodology that follows the IRS Cost Segregation Audit Techniques Guide (Publication 5653). The reclassified components may then qualify for federal §168(k) bonus depreciation on the federal return (100% for qualified property acquired and placed in service after January 19, 2025, subject to eligibility and election rules). South Carolina computes its own depreciation under §168 without the bonus allowance, per S.C. Code §12-6-50, and recovers the reclassified basis over the ordinary MACRS life on the state return instead. The engine ships our own calibrated, nationally-recognized construction cost data.
Related guides
- Bonus depreciation by state: overview
- All 50 states: conformity reference table
- North Carolina bonus depreciation (partial conformity, 15% Year 1)
- Georgia bonus depreciation (decoupled)
- Virginia bonus depreciation (decoupled)
- Form 3115 cost segregation lookback: §481(a) mechanics
- What is cost segregation: the full primer
- Sample cost segregation reports