Executive Summary: The California Decoupling Trap
While federal tax law allows a $1,250,000 Section 179 write-off for tax year 2026, California is one of the strictest non-conforming states in the nation. Under California Revenue & Taxation Code § 17201 and § 24356, the state Section 179 deduction is capped at $25,000 with a phase-out starting at $200,000. Furthermore, California completely disallows 100% federal bonus depreciation.
1. Federal vs. California Section 179 Comparison
| Provision | Federal (IRS) | California (FTB) |
|---|---|---|
| Section 179 Deduction Cap | $1,250,000 | $25,000 Maximum |
| Phase-Out Threshold | $3,130,000 | $200,000 (Phases out at $225k) |
| Bonus Depreciation (IRC § 168k) | 100% Conforming | 0% Disallowed (Full State Add-Back) |
| Primary Filing Form | IRS Form 4562 | Form FTB 3805P (Pass-Through) / FTB 3885 (Corp) |
| Top Tax Rates (2026) | 21% Corporate / 37% Individual | 8.84% Corporate / 13.3% Individual |
2. How the California State Add-Back Is Calculated
Because California disallows excess Section 179 and bonus depreciation in Year 1, your business must maintain two separate depreciation schedules: a Federal Schedule and a California Schedule.
📊 Worked Case Study: $100,000 Equipment Purchase in California
Assume a California manufacturing business purchases $100,000 in industrial equipment (7-year MACRS):
• Federal Return (IRS Form 4562): Claims full $100,000 Section 179 write-off in Year 1 → Federal Basis becomes $0.
• California Return (Form FTB 3805P): Can only claim $25,000 under CA Rev. & Tax Code § 17201.
• Remaining California Basis ($100,000 - $25,000): $75,000.
• California Standard MACRS Year 1 Deduction (14.29%): $75,000 × 14.29% = $10,718.
• Total California Year 1 Deduction: $25,000 + $10,718 = $35,718.
• California State Tax Add-Back Adjustment: $100,000 (Federal) - $35,718 (State) = +$64,282 added back to California taxable income!
3. S-Corporation & LLC Member Level Limitations
In California, the $25,000 Section 179 limitation applies at both the entity level AND the individual shareholder/partner level. If an individual is an owner in multiple California LLCs or S-Corps that each claim $25,000 in Section 179, the total allowable Section 179 deduction passing through to the owner's California personal return (Form 540) is still capped at $25,000.
Calculate Your California Tax Savings & Add-Backs
Select California in our interactive tax engine to compute your exact federal deduction, state $25,000 cap adjustment, and net cash savings.
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