ST Group is a full-service accounting firm working with credit unions, non-profit organizations, construction companies, businesses, and individuals — wherever they are. Audit, tax, and advisory, handled with experience and delivered with care.
ST Group provides audit, tax, and advisory services to clients near and far — from our Sacramento office to businesses and individuals across the country, served securely through our encrypted client portal. We are a full-service firm with particular depth in credit unions, non-profit organizations, construction companies, and ERISA employee benefit plan audits — engagements that demand specialized regulatory knowledge — alongside the businesses and individuals who form the backbone of our practice.
The promise is simple: experienced work, fair pricing, and a CPA who's easy to talk to — the same person, every time, who actually knows your file. Your first consultation is always free: bring your questions and you'll get a plain answer on how we can help.
From annual audits to a quick QuickBooks question — one firm, full service, with specialized industry expertise.
Personal tax preparation and planning that protects what you've earned — deductions and credits fully used, filings done right and on time, and year-round guidance for life's bigger financial decisions.
Accounting, compilation, and advisory support that keeps your business compliant and efficient — clean books, meaningful financial statements, and practical advice for improving margins and cash flow.
Planning, compliance, and preparation for businesses, non-profits, and individuals. We work to make sure you never pay more than the law requires — and never less than it demands.
Setup, cleanup, and training for the most widely used small-business accounting software — so your day-to-day bookkeeping produces numbers you and your CPA can actually rely on.
Supervisory committee audits, agreed-upon procedures, and assurance work for credit unions — a regulatory niche we know deeply.
Audits, Form 990 preparation, and board-level advisory for non-profits — helping mission-driven organizations stay compliant and fundable.
Accounting, job-cost insight, and tax work built for contractors — from financial statements your bonding company will accept to entity and tax planning that fits the industry.
Independent audits of 401(k) and other employee benefit plans that meet ERISA and Department of Labor requirements — done efficiently, with minimal disruption to your HR and payroll teams.
Dates below reflect federal (IRS) and California (FTB) calendars for calendar-year filers. When a due date falls on a weekend or holiday, it moves to the next business day.
| Date | What's due |
|---|---|
| Sep 15, 2026 | Q3 2026 federal estimated tax payment · Extended S-corporation and partnership returns (Forms 1120-S, 1065) |
| Oct 15, 2026 | Extended individual returns (Form 1040) and extended C-corporation returns · Extended California personal returns |
| Jan 15, 2027 | Q4 2026 federal estimated tax payment · CA Q4 personal estimate |
| Feb 1, 2027* | W-2s and 1099-NEC forms due to recipients and to SSA/IRS (Jan 31 falls on a Sunday) |
| Mar 15, 2027 | S-corporation and partnership returns (or extensions) for 2026 tax year |
| Apr 15, 2027 | Individual and C-corporation returns (or extensions) · Q1 2027 estimates · 2026 IRA/HSA contribution deadline · CA personal returns and Q1 estimate |
| Jun 15, 2027 | Q2 2027 federal and CA estimates · CA LLC estimated fee |
California personal estimated payments are weighted — 30% (Q1), 40% (Q2), 0% (Q3), 30% (Q4) — so most CA individual filers make no state estimate payment in September. California LLCs also owe the $800 annual franchise tax by the 15th day of the 4th month of their tax year. Questions about which dates apply to you? Ask us — that's what we're here for.
Current news releases and plain-language tax tips, straight from the source:
On the live site, this section will update itself automatically with the newest IRS headlines.
Send tax documents and receive files back through our encrypted client portal — safer than email, and no account setup required to send us your first documents.
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Call, email, or stop by — we'll be happy to talk through your situation and give you a clear picture of how we can help.
Address 1860 Howe Ave, Suite 260
Sacramento, CA 95825
Phone (916) 424-6233
Fax (916) 424-8559
Email info@stgroupcpa.com