12 tax deadlines California CFOs must track in 2026
Photo by Karola G
Miss a California tax deadline and the damage can be enormous. Penalties and interest start accruing immediately, cash forecasts get distorted, and what should be a routine filing can turn into a line item the board asks about.
For a CFO, this is a financial exposure in a state that stacks federal rules on top of aggressive state, county, and city requirements. With overlapping payroll deposits, estimated payments, information returns, property tax installments, and local filings, the margin for error is very thin.
The 12 deadlines below are the ones that decide whether you remain compliant or not.
1. January 15, 2026: Q4 2025 estimated tax payment (state & federal)
Individuals and corporations generally must remit the fourth quarter estimated tax for 2025 by January 15. Underpayment triggers penalties that can quickly exceed 10% of the balance due (and that’s before interest).
2. February 2, 2026: 1099/W-2 and information return filing deadline
Federal deadline for furnishing and filing Forms W-2 and many 1099 series (including 1099-NEC / 1099-MISC) move to February 2, 2026 when January 31 falls on a weekend. Distribution and filing late can trigger fines per form, often starting at roughly $60 or more if delayed. Plan for compliance early so your accounts payable and HR teams aren’t scrambling.
3. April 1, 2026: 1st quarter California payroll tax reports due
California’s Employment Development Department (EDD) requires quarterly payroll tax returns and deposits (DE 9, DE 9C, DE 3 series and deposits). The first quarter filings for Jan–Mar wages are due April 1, with delinquency after April 30. Payments sent electronically must settle by the timely settlement date to avoid a 15% penalty plus interest (state law).
4. April 15, 2026: Personal & C corporation income tax returns due
California personal income tax (Form 540) and C corporation returns (Form 100) are due on April 15. This date also aligns with first quarter estimated payments for 2026. Extensions to file (not pay) are automatic until October 15, but you must pay the tax by April 15 or face late payment penalties and interest.
In Los Angeles county, municipal business obligations layer on top of state rules. For CFOs managing complex multi-entity returns (especially in entertainment or real estate portfolios), outsourcing parts of compliance can be strategic. Services like KDA Inc Los Angeles tax preparation can streamline all the local filing nuances and help you avoid costly mistakes.
5. June 15, 2026: 2nd quarter estimated taxes
Both federal and state estimated taxes are due June 15. For cash-intensive sectors like real estate or seasonal entertainment enterprises, this is a major cash-flow planning checkpoint. If your fiscal year doesn’t sync with the calendar, deadlines move, so ensure your corporate controller aligns with tax counsel.
6. June 30/July 2, 2026: Property tax appeal window opens
Property taxes in California run on a fiscal cycle with liens assessed January 1. The window to file a property value appeal typically opens July 2 and runs until mid-September (or later if notices were late). The stakes for real-estate heavy portfolios can be in the tens of thousands.
7. July 1, 2026: 2nd quarter payroll filing deadline (CA)
Second quarter payroll tax activity (April–June) and deposits must be transmitted by July 1 to avoid delinquency. This is often overlooked amid mid-year financial reporting crunches.
8. September 15, 2026: 3rd quarter estimated taxes & appeal deadline
Third quarter estimated payments hit September 15. Meanwhile, property assessment appeal periods often close around this time. Filing by this deadline preserves your litigation rights if you’re challenging a county’s valuation, particularly in volatile markets like Los Angeles and San Francisco.
9. October 1/November 2, 2026: 3rd quarter payroll & final settlement window
Third quarter California payroll returns are due October 1; they become delinquent if not filed and paid by the next business deadline (often November 2). This deadline is crucial if your company’s withholding patterns make you a semi-weekly depositor.
10. November 1, 2026: Property tax installment due
The first installment of secured property taxes is legally due November 1, with typical “grace period” through early December in many counties, but penalties begin once that grace period lapses. For real estate portfolios, mis-timing even one large parcel can lead to significant finance charges.
11. January 15, 2027: 4th quarter estimated taxes
This is the fourth quarter due date for 2026 estimated tax liabilities (both state and federal). Meet this date to avoid underpayment penalties that the IRS and FTB enforce stringently.
12. January 31/February 2, 2027: Annual payroll & information returns
Federal annual payroll reconciliations (W-2, 940/941 summaries) and certain 1099 filings are due by January 31, with state information returns following soon after. Confirm state due dates for copies of 1099-K/1099-NEC with FTB because California often piggybacks on federal submission programs.
Sector nuances worth planning for
- Tech startups (VC-backed): Expect tight margins on estimated payments in early growth phases. In hubs like San Francisco, local gross receipts and payroll tax filings (e.g., February 28 San Francisco gross receipts) add complexity beyond state deadlines.
- Entertainment industry: Production tax credits and quarterly withholding can shift estimated tax strategies. Your schedules for passthrough owners’ tax obligations (PTE credits) may demand prepayment planning, especially with the elective PTE regime now extended into 2026-2030.
- Real estate portfolios: Property tax appeals and installment strategies affect cash flows. And missing appeal windows or mis-timing installments, especially for high-value properties, can incur disproportionate costs.
Staying ahead of California’s layered tax calendar means creating a compliance rhythm that ties into your cash-flow forecasts and board planning cycles. Integrate these deadlines into your internal reporting calendar now and loop in your tax advisors because even small changes in filing or deposit timing can have outsized impacts on your cost of capital and stakeholder confidence.