What types of business tax returns do you prepare?

We prepare all business entity tax returns including Form 1120 (C-Corp), Form 1120S (S-Corp), Form 1065 (Partnership), Schedule C (Sole Proprietor), and multi-member LLC returns. We also handle franchise tax reports, sales tax filings, and payroll tax returns for Texas businesses.

How much does business tax preparation cost?

Our business tax preparation starts at $750 for simple Schedule C filings and ranges up to $3,500+ for complex multi-state corporate returns. After our initial consultation, we provide a transparent quote based on your specific entity type, number of transactions, and complexity. There are never hidden fees.

When are business tax returns due?

It depends on your entity type. Partnerships and S-Corps are due March 15th, while C-Corps and sole proprietors (Schedule C) are due April 15th. We can file extensions if needed, giving you until September 15th or October 15th respectively. Texas franchise tax reports are due May 15th annually.

Should my business be an LLC or S-Corp?

The right entity depends on your income level, business type, and growth plans. Generally, S-Corps can save on self-employment taxes once your net income exceeds $60,000, but LLCs offer more flexibility. We provide entity selection consulting to analyze your specific situation and can help you convert if beneficial.

What business expenses can I deduct?

Common deductions include office rent, equipment, supplies, professional services, insurance, travel, meals (50% deductible), home office expenses, vehicle costs, and employee wages. We review your expenses to ensure you're capturing all legitimate deductions while maintaining proper documentation.

Do you provide year-round support or just at tax time?

We provide comprehensive year-round support including quarterly tax planning sessions, estimated tax calculations, quick questions via email or phone, and proactive tax-saving recommendations. You work with the same team throughout the year, not just during tax season.

Home > Business Tax Services > The Complete Guide to C-Corporation Taxation > C-Corporation Tax Services

C-Corporation Tax Services

Strategic C-Corp tax preparation for startups, growth companies, and established corporations. Form 1120, QSBS planning, and proactive tax strategy.

Get Started on your 1120

C-Corporation Tax Services at a Glance:

Form 1120 preparation with all required schedules (K, L, M-1, M-2)
QSBS (Section 1202) planning and compliance
Entity selection analysis: C-Corp vs S-Corp vs LLC
Quarterly estimated tax calculation and payment planning
State corporate tax filings for all 50 states
Year-round tax planning to minimize double taxation

What You Need to Know About C-Corp Taxation:

C-Corps pay a flat 21% federal income tax rate on all taxable income
Double taxation applies when profits are distributed as dividends (corporate tax + shareholder dividend tax)
QSBS (Section 1202) can exclude up to $15 million in capital gains under OBBBA 2025
Form 1120 is due April 15 for calendar-year corporations (6-month extension available)
Most small businesses should NOT be C-Corps unless raising VC, pursuing QSBS, or reinvesting all profits

Complete C-Corporation Tax Services

Everything your C-Corp needs for accurate, strategic tax compliance

Form 1120 Preparation

Comprehensive preparation of your corporate income tax return

Form 1120 main return
Schedule K (shareholders and ownership)
Schedule L (balance sheet)
Schedule M-1 (book-to-tax reconciliation)
Schedule M-2 (retained earnings analysis)
All required attachments and elections

QSBS Planning & Compliance

Maximize Section 1202 qualified small business stock benefits

QSBS eligibility analysis
Stock basis tracking and documentation
Holding period monitoring
Gross asset threshold compliance
OBBBA 2025 tiered exclusion planning
Exit strategy coordination

Entity Selection & Conversion

Determine the right structure and navigate conversions

C-Corp vs S-Corp vs LLC analysis
Entity conversion planning
Built-in gains tax modeling
E&P and AAA tracking
State-level considerations
Ongoing structure optimization

Tax Planning & Strategy

Proactive planning to minimize overall tax burden

Double taxation minimization strategies
Reasonable compensation analysis
Retirement plan optimization
Fringe benefit structuring
Estimated tax planning
Multi-year projections

Who We Work With

C-Corporation Clients We Serve: From startups to established corporations

VC-Backed Startups

Companies raising institutional capital need C-Corp structure. We help with entity setup, QSBS compliance from day one, and coordination with your fundraising timeline.

Founder-Led Growth Companies

Business owners building toward significant exits benefit from QSBS planning. We track qualification requirements and optimize your exit strategy.

Established C-Corporations

Mature C-Corps need ongoing compliance and strategic planning. We handle annual Form 1120 preparation and look for opportunities to reduce your tax burden.

S-Corps Converting to C-Corp

Companies converting for VC raises or QSBS planning face complex transitions. We manage the conversion process and restart your QSBS clock properly.

LLCs Electing C-Corp Taxation

LLCs can elect C-Corp taxation via Form 8832 for QSBS benefits. We handle the election and ongoing compliance.

Delaware Corporations

C-Corps are standard for VC-backed companies. We handle both federal and Delaware franchise tax requirements.

Our C-Corp Tax Preparation Process

From documents to filed return in 5 steps

Initial Consultation

We review your corporate structure, ownership, and tax situation. For new clients, we assess whether C-Corp is the right structure and discuss QSBS planning opportunities.

Document Collection

We provide a customized checklist for your situation. Secure portal for uploading financial statements, prior returns, and supporting documentation.

Return Preparation

Our team prepares your Form 1120 with all required schedules. We reconcile book and tax differences, calculate any estimated tax adjustments, and prepare state returns.

Review & Approval

You review the complete return package. We discuss tax planning opportunities, QSBS status, and strategies for the upcoming year.

Filing & Year-Round Support

We file your return and confirm acceptance. Vouchers for estimated taxes, available planning updates, and any mid-year changes.

Documents Needed for C-Corp Tax Preparation

Prior year Form 1120 (if applicable)
Year-end financial statements
Trial balance or general ledger
Bank and brokerage statements
Shareholder ownership records

Payroll records and W-2 summaries
Officer compensation details
Asset purchases and dispositions
Loan documents (shareholder loans)
State registrations and filings

Transparent C-Corporation Pricing

Upfront estimates based on complexity

Service	Includes	Best For	Starting Price
Form 1120 - Basic	Federal return, all schedules, e-filing	Simple C-Corps, single state, minimal transactions	$1,500
Form 1120 - Standard	Federal + state returns, depreciation schedules, M-1/M-2	Operating C-Corps, multiple assets, distributions	$2,500
Form 1120 + QSBS Tracking	Standard return + QSBS compliance documentation	Startups and growth companies planning exits	$3,500
Multi-State C-Corp	Federal + multiple state returns, apportionment	C-Corps operating in 3+ states	$4,000
C-Corp Tax Planning Package	Return preparation + quarterly planning + projections	Growing companies needing year-round strategy	$6,000/year
Entity Conversion Planning	S-Corp to C-Corp or C-Corp to S-Corp analysis	Companies considering structure changes	$1,500

* Prices are starting points based on typical complexity. Final quote provided after initial consultation. State returns priced separately if not included in package.

Special C-Corp Situations We Handle

QSBS Exit Planning

Coordinating stock sales to maximize Section 1202 exclusion. Pre-OBBBA vs. post-OBBBA stock tracking, tiered holding period optimization, and Section 1045 rollover strategies.

VC Fundraising Preparation

Getting your books and tax compliance ready for due diligence. Clean cap table documentation, proper stock issuance records, and QSBS qualification verification.

S-Corp to C-Corp Conversion

Converting for fundraising or QSBS benefits. Timing the revocation, restarting the QSBS clock, and coordinating with investors.

C-Corp to S-Corp Conversion

Converting to avoid ongoing double taxation. Built-in gains tax analysis, E&P distribution planning, and AAA tracking setup.

Reasonable Compensation Analysis

Documenting market-rate compensation to support salary deductions. IRS reasonable compensation standards and industry benchmarking.

Accumulated Earnings Tax Planning

Avoiding the 20% penalty tax on excess retained earnings. Documenting business purposes for retained profits and planning strategic distributions.

Why Business Owners Choose SDO for C-Corp Taxes

Entity Structure Expertise
We don't just file returns—we help you determine if C-Corp is right for your situation. Many clients come to us after realizing their current structure isn't optimal. We provide honest analysis of whether C-Corp, S-Corp, or LLC serves you better.

QSBS Planning Focus
QSBS can save millions in taxes on a successful exit, but only if you plan properly from the start. We track QSBS qualification requirements, monitor holding periods, and coordinate exit timing to maximize your exclusion under OBBBA 2025 rules.

Year-Round Relationship
C-Corps need quarterly attention—estimated taxes, planning opportunities, and mid-year adjustments. We don't disappear after filing season. Monthly and quarterly touchpoints keep your tax strategy on track.

Startup & Growth Company Experience
We work with VC-backed startups, founder-led growth companies, and businesses planning significant exits. We understand the unique tax considerations for high-growth C-Corps.

Ready to Optimize Your C-Corp Tax Strategy?

Whether you need Form 1120 preparation, QSBS planning, or want to evaluate if C-Corp is right for your situation, we can help.

Schedule C-Corp Consultation

C-Corporation Tax FAQs

Common questions about 1120 taxation and our services

What tax rate do C-Corporations pay?

C-Corporations pay a flat 21% federal income tax rate on all taxable income, regardless of the amount. State corporate income taxes add 0-12% depending on your state. When profits are distributed as dividends, shareholders pay an additional 0-23.8% (qualified dividend rate plus potential Net Investment Income Tax), creating the "double taxation" that C-Corps are known for.

When is Form 1120 due?

Form 1120 is due on the 15th day of the 4th month after your fiscal year-end. For calendar-year corporations (most common), this means April 15. A 6-month automatic extension is available via Form 7004, extending the deadline to October 15. The extension is to file, not to pay—estimated taxes are still due by the original deadline.

What is QSBS and how does it benefit C-Corp owners?

Qualified Small Business Stock (Section 1202) allows shareholders to exclude capital gains when selling C-Corp stock. Under OBBBA 2025, the exclusion is up to $15 million (increased from $10M) with tiered holding periods: 50% exclusion at 3+ years, 75% at 4+ years, and 100% at 5+ years. For founders with successful exits, QSBS can mean zero federal tax on millions in gains.

Should my startup be a C-Corp?

If you're raising venture capital, likely yes—VCs typically require C-Corp structure. If you're bootstrapping and taking profits as distributions, probably not—S-Corp or LLC may result in lower overall taxes. The decision depends on your funding plans, expected exit timeline, and whether QSBS benefits apply to your situation.

How do I minimize double taxation in a C-Corp?

Strategies include: (1) paying reasonable salary to owner-employees (deductible to the corp, taxed once), (2) maximizing retirement contributions, (3) reinvesting profits instead of distributing dividends, (4) structuring shareholder loans with deductible interest, and (5) utilizing tax-advantaged fringe benefits. If you're building for a QSBS-eligible exit, the "double taxation" on an eventual sale may be eliminated entirely.

Can I convert my C-Corp to an S-Corp?

Yes, by filing Form 2553 with IRS consent. However, conversion triggers potential built-in gains tax (21% on appreciated assets sold within 5 years of conversion) and requires tracking accumulated earnings and profits. Generally, earlier conversion is easier—the longer you operate as a C-Corp, the more complexity in converting.

What records do I need to keep for QSBS?

Document: (1) stock issuance dates and purchase prices, (2) gross asset values at stock issuance (must be under $75M), (3) evidence of original issuance (not purchased from another shareholder), (4) active business qualification (80%+ of assets in active business), and (5) confirmation you're not in an excluded business category. These records are critical if IRS questions your exclusion.

Do you handle Delaware C-Corp franchise taxes?

Yes. Delaware C-Corps must file annual franchise taxes separate from federal returns. We calculate your franchise tax using whichever method results in a lower tax (Authorized Shares Method or Assumed Par Value Capital Method) and coordinate filing with your federal return.