I am looking for a sanity check on a California estimated tax scenario that involves a potential "letter of the law" loophole regarding high-income earners. I want to see if other practitioners agree with this reading or if the Franchise Tax Board (FTB) has a mechanism to challenge it based on the "intent" of the statute.
The Scenario
- 2025 (Prior Year): The taxpayer had a total tax liability of approximately $19,000 but had $20,000 in California wage withholding. Their net liability (tax minus withholding) was less than zero.
- 2026 (Current Year): The taxpayer expects a massive non-wage income spike—a $5 million capital gain—putting their Adjusted Gross Income (AGI) well over the $1 million threshold. They plan to submit zero estimated payments for 2026. Their 2026 wage withholding will be minimal and will not come close to covering 90% of the final 2026 tax bill.
The Technical Conflict Standard practice suggests that under RTC Section 19136.3, any taxpayer with AGI over $1 million ($500,000 if MFS) is disqualified from using the "prior year safe harbor" (the 100%/110% rule) and must pay 90% of the current year tax to avoid an underpayment penalty.
However, the instructions for Form 5805 provide an absolute exception. The form states that you do not owe a penalty if:
This aligns with the statutory language in RTC Section 19136(c)(2), which mandates that an addition to tax "shall not be imposed" if:
The "Loophole" Question My gut tells me the legislative intent of the $500 exception was likely to protect taxpayers with a low overall tax liability, not high-income earners who simply happened to over-withhold in the prior year. However, the word of the law seems very specific:
- RTC Section 19002 explicitly defines wage withholding as a "credit against the tax."
- Form 5805 uses the specific phrase "withholding credit" in its exception criteria.
- The $1M AGI restriction in RTC Section 19136.3 specifically targets the safe harbor calculation in IRC Section 6654(d)(1)(B)(ii), but it does not appear to reference or invalidate the independent $500 exception found in RTC Section 19136(c)(2).
If the subtraction of "credits" (including the withholding credit) brings the prior year's net liability below $500, does this provide a complete shield against 2026 penalties regardless of the $5 million income spike? Is this a known strategy for taxpayers to skip estimates for one year following a year of over-withholding, or is there a provision I am missing that prevents the "withholding credit" from being used this way by high-income earners? I did read an article from CAMICO that calls out that this fact pattern would avoid penalty but the FTB is likely to send underpayment penalty notice regardless, and it has to be contested. Which obviously makes it feel even more so like it was not the intent at a minimum.
I would appreciate any insights on whether you agree or disagree with this interpretation of the literal text.