Resources
Tax & Accounting Resources
Deadlines, checklists, and reference links for individuals and small businesses working with a Certified Public Accountant in San Mateo.
Key tax deadlines
- January 15 — Q4 estimated tax payment due for the prior year.
- January 31 — W-2 and 1099-NEC forms due to recipients and the IRS.
- March 15 — Partnership and S corporation returns due (calendar-year filers).
- April 15 — Individual returns, C corporation returns, and Q1 estimates due.
- June 15 — Q2 estimated tax payment due.
- September 15 — Q3 estimates and extended partnership / S corp returns due.
- October 15 — Extended individual returns due.
Dates shift to the next business day when they fall on a weekend or holiday. Call the office to confirm deadlines that apply to your situation.
Tax document checklist
- • Photo ID and Social Security numbers for everyone on the return
- • W-2s, 1099s, K-1s, and retirement or Social Security statements
- • Mortgage interest (1098), property tax, and charitable giving records
- • Business income and expense summaries, including mileage logs
- • Brokerage and digital asset transaction reports with cost basis
- • Health coverage forms (1095-A/B/C) and HSA statements
- • Estimated tax payments made during the year
- • Last year's federal and state returns, if you are new to the firm
Guides by topic
Individual tax resources
Withholding and estimated payments, itemizing versus the standard deduction, education and childcare credits, and how California conformity differs from federal rules.
Small business tax resources
Entity selection, reasonable compensation for S corporation owners, payroll tax deposits, 1099 filing obligations, and recordkeeping systems that hold up under review.
Digital asset tax information
Every sale, swap, or spend of a digital asset is generally a taxable event. Keep exchange exports, wallet histories, and cost-basis records for each transaction so gains and losses can be reported accurately.
Recordkeeping guidance
Keep supporting documents for at least three years after filing — seven for records tied to property, worthless securities, or bad debts.
Secure client portal
Send tax documents to our office without email. The portal lets you upload W-2s, 1099s, statements, and business records to a private, encrypted area, and exchange secure messages with us about your return.
Open the client portalStill have questions?
Read our frequently asked questions or call the San Mateo office directly.