Startup Tax Calendar — Missouri & Federal
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C --> D["State\nDeadlines"]
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Disclaimer: Tax deadlines change. Verify all dates with your CPA and at irs.gov and dor.mo.gov each year. Missing tax deadlines results in penalties and interest.
Monthly Obligations (Ongoing)
| Obligation | Due | Where |
|---|---|---|
| Missouri Sales Tax (if registered, monthly filer) | 20th of following month | mytax.mo.gov |
| Federal Payroll Tax Deposits | Semi-weekly or monthly based on lookback period | EFTPS (eftps.gov) |
| Missouri Income Tax Withholding Deposits | Monthly (most small employers) | mytax.mo.gov |
| Missouri Unemployment Insurance | Quarterly (see below) | uinteract.labor.mo.gov |
Quarterly Obligations
| Obligation | Q1 Due | Q2 Due | Q3 Due | Q4 Due |
|---|---|---|---|---|
| Federal Estimated Tax (individuals/pass-through) | Apr 15 | Jun 15 | Sep 15 | Jan 15 next year |
| Missouri Estimated Tax | Apr 15 | Jun 15 | Sep 15 | Jan 15 next year |
| Employer Quarterly Federal Tax Return (Form 941) | Apr 30 | Jul 31 | Oct 31 | Jan 31 |
| Missouri Employer Tax Return (MO-941) | Apr 30 | Jul 31 | Oct 31 | Jan 31 |
| Missouri Unemployment Insurance (Form MODES-4) | Apr 30 | Jul 31 | Oct 31 | Jan 31 |
| Quarterly Sales Tax (Missouri, if quarterly filer) | Apr 30 | Jul 31 | Oct 31 | Jan 31 |
Annual Obligations
January
- Jan 31: W-2s to employees; W-3 to SSA
- Jan 31: 1099-NECs to contractors (≥ $600 paid); file with IRS
- Jan 31: Employer's Annual Federal Unemployment Tax (Form 940)
- Jan 31: Missouri Annual Reconciliation of Income Taxes Withheld (MO-W3)
March
- Mar 1: Delaware Franchise Tax (if Delaware C-Corp) — minimum $400, often higher
- Mar 15: S-Corporation tax return (Form 1120-S) — or extension request
- Mar 15: Partnership return (Form 1065) — or extension request
- Mar 15: Missouri S-Corp/Partnership return — same date as federal
April
- Apr 15: Individual income tax returns (Form 1040) — or extension request
- Apr 15: C-Corporation tax return (Form 1120) — or extension request
- Apr 15: Missouri individual income tax return — same date as federal
- Apr 15: First quarter estimated taxes due (federal and Missouri)
May–August
- May 15: Missouri Annual Report for LLCs and corporations (verify — tied to registration anniversary)
- Jun 15: Second quarter estimated taxes due
- Jul 31: Missouri Secretary of State annual report (varies by entity/anniversary month)
September
- Sep 15: Third quarter estimated taxes due
- Sep 15: Extended S-Corp and partnership returns due
October
- Oct 15: Extended individual and C-Corp returns due
December
- Year-end tax planning: Meet with CPA before Dec 31 to time income/expense
- Dec 31: Last day to make equipment purchases for Section 179 deduction
- Dec 31: Last day to make retirement plan contributions that affect current year (varies by plan type)
- Dec 31: Last day to recognize capital losses to offset gains
Missouri-Specific Annual Requirements
Missouri Secretary of State Annual Report
- LLCs: Annual registration fee due by anniversary of formation
- Corporations: Annual report due by anniversary
- Fee: ~$45 online
- File at: sos.mo.gov
- Consequence of missing: Administrative dissolution after ~2 years
Missouri Registered Agent
- Maintain a registered agent at all times
- Notify SOS within 30 days if registered agent changes
- File at: sos.mo.gov
Delaware Foreign Registration (if Delaware Corp operating in Missouri)
- Annual report to Missouri SOS
- Certificate of Good Standing from Delaware may be required annually
- Maintain Delaware franchise tax payments (March 1 annually)
Key Tax Forms for Startups
| Form | What It Is | Who Files |
|---|---|---|
| 1120 | C-Corporation income tax return | C-Corps |
| 1120-S | S-Corporation income tax return | S-Corps |
| 1065 | Partnership return | Partnerships, LLCs taxed as partnerships |
| 1040 + Schedule C | Sole proprietor / single-member LLC | Solo founders, single-member LLCs |
| 941 | Quarterly payroll tax return | Any employer |
| 940 | Annual federal unemployment tax | Any employer |
| W-2 | Employee wages and withholding | For each W-2 employee |
| 1099-NEC | Non-employee compensation | For each contractor paid ≥ $600 |
| 83(b) Election | Restricted stock tax election | Founders with vesting (file within 30 days) |
| MO-1120 | Missouri corporate income tax | Missouri C-Corps and foreign corps with MO income |
| MO-1040 | Missouri individual income tax | Missouri residents |
| MO-941 | Missouri employer withholding return | Missouri employers |
| MODES-4 | Missouri unemployment insurance | Missouri employers |
R&D Tax Credit — Don't Leave Money on the Table
Many Missouri tech startups qualify for R&D tax credits and don't claim them.
Federal R&D Credit (Section 41):
- For pre-revenue startups: Can offset up to $500,000/year in payroll taxes (employer FICA)
- For profitable companies: Credit reduces income tax liability
- Qualifying activities: Software development, product R&D, process improvement, testing
- What qualifies: Employee wages, contractor costs, and supply costs for qualifying activities
- Typical credit: 6–8% of qualifying R&D spend (simplified method)
Missouri R&D Credit:
- 15% of Missouri qualified research expenses above a base amount
- Carryforward: 10 years
- Apply separately at dor.mo.gov
Practical steps:
- Track time spent by developers on qualifying activities (time logs or estimates)
- Engage an R&D tax credit specialist (many work on contingency)
- File Form 6765 with federal return; MO-TC with Missouri return
Firms specializing in startup R&D credits: alliantgroup, Leyton, Source Advisors
Section 179 and Bonus Depreciation
Section 179 Deduction:
- Deduct the full cost of qualifying equipment and software in the year purchased
- 2024 limit: $1,160,000 (verify current year limit)
- Qualifying property: computers, servers, software, office equipment, vehicles (limits apply)
- Must be placed in service by December 31
Bonus Depreciation:
- Additional first-year depreciation on qualifying property
- 2023: 80%; 2024: 60%; phases down each year (check current year)
- Can create a loss that carries forward
Practical note: Buy equipment before December 31 if you want the deduction this year.
Startup Tax Strategy Checklist
YEAR 1
[ ] Choose correct entity type (LLC vs. C-Corp) — this affects lifetime tax
[ ] File 83(b) elections within 30 days of stock grants
[ ] Register for all applicable Missouri taxes before first transaction
[ ] Set up payroll properly before first W-2 employee
[ ] Separate personal and business finances immediately
[ ] Track all expenses with receipts from day one
EVERY YEAR
[ ] Meet with CPA in November for year-end tax planning
[ ] Review R&D tax credit eligibility
[ ] Track equipment purchases for Section 179
[ ] Review entity structure — still optimal?
[ ] File estimated taxes quarterly (avoid underpayment penalty)
[ ] Maintain clean books — don't let reconciliation slip
BEFORE FUNDRAISING
[ ] Ensure clean cap table
[ ] Confirm all founder equity is properly documented
[ ] Verify 83(b) elections were filed on time
[ ] QSBS qualification confirmed with attorney (if C-Corp)
[ ] Review any state tax credits available
BEFORE AN ACQUISITION
[ ] QSBS analysis — how much is excludable?
[ ] Structure of deal (asset vs. stock) has massive tax implications
[ ] Installment sale treatment for earn-outs
[ ] Engage M&A tax advisor early in processNonpartisan informational resource for Missouri — District 2 — not legal, medical, or financial advice. Source: dougdevitre/access-to-business.
Paid for by Matt Grant for Congress.