C-Corp Tax Filing Checklist: The Definitive Guide to Corporate Filing 

Navigating tax season for a C-Corporation can feel like a significant responsibility. Unlike a pass-through entity, a C-Corp is a separate legal and taxable entity, making its tax filings more involved. But with a clear checklist and a solid understanding of the deadlines, you can get through it with confidence.  This guide is designed for business owners in the USA who have chosen to incorporate as a C-Corporation, helping you understand the necessary forms, documents, and key dates to stay compliant with the IRS.  Table of Contents C-Corp Taxation Explained First, a quick refresher. A C-Corporation is a legal entity entirely separate from its owners. A key distinction is that the C-Corp itself pays corporate income taxes on its profits. Then, when it distributes dividends to its shareholders, those individuals are taxed on that income as well—a process commonly referred to as double taxation.  Despite this, C-Corps offer significant advantages for certain businesses, such as unlimited growth potential, the ability to raise capital by selling stock, and robust legal liability protection for shareholders. This structure is often favored by startups with plans for venture capital funding or eventual public offerings.  The Most Important Deadline to Know For a calendar-year C-Corp, the main deadline for filing your federal return is April 15, 2026 (for the 2025 tax year). This is also the due date for your first quarterly estimated tax payment. For the 2026 tax year, the deadline will be April 15, 2027.  If you need more time, you can file for an extension using Form 7004, which gives you an additional six months to file, pushing your deadline to October 15, 2026. However, remember that an extension to file is not an extension to pay. If you expect to owe any tax, you must pay it by the April 15 deadline to avoid penalties and interest.  The C-Corp Tax Filing Checklist Let’s get down to business. Here are the items you’ll need to prepare for your C-Corp tax filing. 1. Essential Financial Records Start by getting your financial house in order. Make sure invoices and receipts are organized and complete.  2. Key IRS Forms Feeling a bit overwhelmed by the list of forms? Don’t worry—you don’t have to be a tax expert to understand the essentials. Here’s a breakdown of the most important forms you’ll encounter and a heads-up on what to watch out for.  3. Don’t Forget These Details! A few small mistakes can lead to big problems. Double-check these items before filing.  The Cost of Missing a Deadline Filing a C-Corp’s tax return late can be costly, and the IRS imposes two main types of penalties:  If both penalties apply in the same month, the late filing penalty is reduced to 4.5%, so the combined monthly penalty is 5%.  If a return is more than 60 days late, the minimum penalty is the lesser of $510 or 100% of the unpaid tax. This is an increase from the $485 penalty that applied for the 2024 tax year.  Remember, interest is also charged on all unpaid amounts, which can add up quickly. It’s always best to file on time even if you can’t pay the full amount due. Get Ready for a Smoother Tax Season Preparing for a C-Corp’s tax filing can feel like a big responsibility. But with a clear plan and the right tools, it’s entirely manageable. By proactively gathering your documents and paying close attention to deadlines, you can minimize stress and avoid costly penalties.  Disclaimer: The information provided in this guide is for informational purposes only and does not constitute legal or tax advice. Tax rules are subject to change, so always check IRS.gov or consult with a professional accountant or tax advisor for your specific situation.  This is where having a reliable accounting system can make all the difference. When all your financials—from income and expenses to payroll—are organized and synced in one place, generating the reports you need for your tax professional (or for filing yourself) becomes a streamlined process. Fynlo is designed to simplify these tasks, so you can focus on what you do best: running your business. Ready to see how Fynlo can transform your tax prep? Schedule a call with our experts to find out more!  You may also like these articles: 

LLC vs Inc.: Everything You Need to Know

Choosing a business structure is like picking the right tool for a job—each has its strengths, quirks, and costs. For new entrepreneurs, the Limited Liability Company (LLC) and Corporation (Inc.) are two of the most popular options in the U.S. Both protect your personal assets, but they differ in taxes, management, ownership, and paperwork. This guide breaks it all down in plain English and a clear comparison table, so you can choose the structure that fits your business dreams. Let’s get started! Table of Contents What is an LLC? A Limited Liability Company (LLC) is like bubble-wrap for your personal assets: it shields them from business debts and lawsuits while remaining simple to run. LLC owners, called members, enjoy liability protection with fewer formalities than a corporation. To form an LLC, you file Articles of Organization with your state’s Secretary of State and pay a fee—usually between $50 and $500 (e.g., $50 in Colorado; $500 in Massachusetts). While an Operating Agreement isn’t required in every state, it’s a smart way to spell out ownership, profit splits, and decision-making rules.  Fun Fact: LLCs existed in limited form starting in the late 1970s, but their popularity has exploded since the mid-1990s. In recent years, LLCs have become the most common structure chosen by small-business owners, reflecting their appeal to modern entrepreneurs. What is an Inc. (Corporation)? A corporation is a separate legal person with shareholders, a board, and more built-in formality. You file Articles of Incorporation (fees range from $90 in Delaware to $125 in New York), adopt bylaws, and hold annual shareholder and board meetings. Corporations come in two tax flavors:  Fun Fact: Although corporations account for roughly 8% of all business tax returns, they generate about 60% of total U.S. business receipts, underscoring how most revenue still flows through corporate entities.  Key Differences at a Glance Below we compare five critical areas: liability protection, taxation, management, ownership, and compliance.  Comparison Table: LLC vs. Inc. Factor  LLC  Inc. (C Corp)  Inc. (S Corp)  Liability  Members protected unless they commit fraud/negligence. Courts pierce veil very rarely.  Shareholders protected. Veil-piercing more common than with LLCs.  Same as C Corp.  Taxation  Pass-through (Schedule C/K-1); can elect C/S Corp status; Members pay self-employment tax on profits by default.  Double taxation: 21% corporate tax + dividend tax (0%–20%).  Pass-through; no self-employment tax on distributions; strict limits.  Management  Flexible: member-managed or manager-managed; no board or meetings required.  Formal: board + officers; annual meetings and minutes mandatory.  Same as C Corp.  Ownership  Unlimited members; no stock; transfers need approval.  Unlimited shareholders; stock easy to sell; ideal for VC.  Max 100 U.S. shareholders; one stock class.  Compliance  Minimal: annual report (fees $0–$500) and basic bookkeeping.   High: adopt bylaws, hold annual meetings and minutes; several thousand dollars per year.   High: same formalities as C Corp plus S-Corp eligibility upkeep; several thousand dollars per year.  Best For  Small businesses, freelancers, hands-on owners.  Scalable startups, VC-funded ventures, public companies.  Small firms wanting pass-through taxation with corporate structure.  1. Liability Shield  Both LLCs and corporations protect personal assets, but the strength of that shield depends on following the rules.  2. Taxes  Below is a condensed overview of how each structure is taxed, focusing on key points a newcomer needs to know. LLC (Default Pass-Through):  LLC Electing S-Corp Status (Optional):  C-Corp (Traditional Corporation):  S-Corp (Standalone Election):  Taxation Summary Table:  Structure  Entity Tax Rate  Owner Tax Treatment  Self-Employment Tax on Profits?  Key Notes  LLC (Default) 0% (pass-through) Owner reports on Schedule C or K-1 → Form 1040 Yes, 15.3% on net earnings Single-member uses Schedule C; multi-member files 1065 → K-1. QBI deduction up to 20%. LLC → S-Corp 0% (pass-through) Owner takes reasonable salary (W-2); rest is dividends Only on salary (FICA) Savings vs. 15.3% if distributions > salary; requires payroll setup. LLC → C-Corp 21% Profits taxed at 21% → dividends taxed again (0%–20%) — Potential double taxation; can retain earnings; access to corporate credits. C-Corp (Standalone) 21% Dividends taxed at 0%–20% on shareholders — Traditional corporate structure; double taxation. S-Corp (Standalone) 0% (pass-through) Owner salary (W-2) + distributions via K-1 Only on salary (FICA) Must meet eligibility (≤ 100 U.S. shareholders, one stock class). 3. Management Style  4. Ownership Flexibility  5. Compliance & Cost  LLC  C Corp  S Corp Pros and Cons of LLC vs. Inc. LLC Pros  LLC Cons  Inc. Pros  Inc. Cons  Which Should You Choose? The choice between an LLC and Inc. depends on your business goals, size, and growth plans:  Need Help Deciding? At Fynlo, we understand that choosing the right business structure can feel overwhelming. Our accounting software and expert team are here to simplify the process, from formation to tax planning. Whether you’re leaning toward an LLC or a corporation, we can help you navigate the paperwork, optimize your taxes, and stay compliant.  Ready to get started? Schedule a call with Fynlo today to discuss your business goals and find the perfect structure for your success. Let’s build your dream business together!  You may also like these articles: 

Tax Filing Guide for S Corp, C Corp and LLC

Picking the right business structure is a big deal, and taxes are a huge part of that decision. In this article, we’re breaking down the tax filing side of things for C Corps, S Corps, and LLCs, so freelancers and business owners can get a handle on the forms and deadlines for each. If you’re looking for a broader comparison, Choosing the Best Business Structure for Freelancers is a solid starting point!  The article was last updated as of 4 March 2025. Keep in mind that tax rules and limits can change, so be sure to watch out for updates or consult a tax professional for the latest information.  Table of Contents Brief Highlights: Comparing C Corp, S Corp and LLC Here’s a quick rundown of the three business structures to give you the big picture. In the next sections, we’ll break down the details of tax treatment and the specific forms you’ll need to know. It’ll all come together as we go.  Category  S Corporation (S Corp)  C Corporation (C Corp)  Limited Liability Company (LLC)  Tax Forms  – Form 1120-S– Shareholders file Schedule K-1 on personal returns  – Form 1120 – Shareholders report dividends on personal returns  Depends on tax classification. See LLC section.  Filing Deadlines  March 15 2025*; extensions available  April 15 2025*; extensions available  Depends on tax classification. See LLC section.  State Taxes  Varies; some states do not recognize S Corp status Subject to state corporate income taxes  Subject to state taxes depending on classification  Eligibility Requirements  – Must be a domestic business– Up to 100 shareholders – Individuals only  – No limit on shareholders– Can include foreign and corporate owners  – No ownership restrictions – Flexible member structure  Ownership Restrictions  – Max 100 shareholders– One class of stock– U.S. citizens/residents only  – Unlimited shareholders– Can issue multiple stock classes  – No restrictions– Members can be individuals, corporations, or foreign entities  Compliance Requirements  – Annual meetings– Shareholder voting– File annual reports  – Annual meetings– Corporate governance– Strict record-keeping  – Varies by state– Fewer formalities than corporations  Average Formation Costs#  ~$1,200  ~$633  ~$50-$500 depending on state  Fundraising Ability  – Limited– Cannot issue preferred stock  – High– Can issue both common and preferred stock  Limited unless electing C Corp tax treatment  Dividend Taxation  Distributions taxed once at shareholder level  Dividends taxed twice (corporate and shareholder level)  Not applicable unless taxed as C Corp  Payroll Tax Implications  Must pay reasonable salary to shareholder-employees  Corporate officers are employees subject to payroll taxes  Members typically pay self-employment tax unless S Corp election made  Passive Income Limits (such as rent, interest, or certain royalties)  Passive income limited to 25% of gross receipts  No passive income limitations  No passive income restrictions  Liability Protection  Protects shareholders’ personal assets  Protects shareholders’ personal assets  Protects members’ personal assets  Conversion Flexibility  Can convert to C Corp; changing to LLC requires dissolution  Can convert to S Corp or LLC with filings and approvals  Can elect S Corp/C Corp taxation; conversions depend on state rules  Foreign Ownership  Not allowed  Allowed  Allowed  Administrative Burden  Higher than LLC; less than C Corp  High due to strict governance requirements  Low; fewer formalities required  Key Tax Advantages  – Avoids double taxation– QBI deduction available  – Potential for certain deductions not available to pass-through entities– Can deduct health insurance premiums for employees  – Flexible tax treatment (can choose to be taxed as a partnership, S corp, or C corp)– Simpler tax compliance than C-corp if taxed as a partnership  Key Tax Disadvantages  – Reasonable salary requirement– Limitations on QBI deduction for certain businesses  – Double taxation– More complex tax compliance  – Members subject to self-employment tax (unless taxed as C-corp)– Less established than C-corps in some states  Best For  Small businesses seeking tax savings through pass-through taxation  Larger businesses seeking growth through investment and stock issuance  Startups, freelancers, or small businesses needing flexibility  * For calendar-year corporations, Form 1120 is due on April 15, and Form 1120-S is due on March 15. For fiscal-year corporations, the deadline is the 15th day of the fourth month (1120) or third month (1120-S) after the fiscal year ends. # Formation costs vary by state and the scope of professional services.  S Corporations Tax Filing S corps offer a unique tax structure, blending the legal benefits of a corporation with the tax advantages of a partnership. This pass-through taxation model avoids the double taxation burden of C corporations, making it an attractive option for many small businesses.   Pass-Through Taxation One of the most significant advantages of an S corporation is its pass-through taxation model. Unlike C corporations, which are subject to double taxation (taxed at both the corporate and shareholder levels), S corps do not pay federal income tax at the corporate level. Instead, the corporation’s profits and losses are passed through to the shareholders, who report them on their individual tax returns (Form 1040). This structure avoids the double taxation burden and can result in significant tax savings for business owners.  Form 1120-S Form 1120-S, the U.S. Income Tax Return for an S Corporation, is the primary form S corps use to report income, deductions, gains, and losses to the IRS. It ensures the corporation’s financial activity is accurately reported and provides shareholders with the information needed to complete their individual tax returns.  The form is due by March 15th for calendar-year taxpayers (or the 15th day of the third month after the fiscal year ends). If additional time is needed to prepare the return, S corps can request an extension using Form 7004, which grants an automatic six-month extension. However, it’s important to note that an extension to file does not extend the deadline for paying any taxes owed. Estimated tax payments must still be made by the original due date to avoid penalties and interest.  Schedule K-1 Schedule K-1 details each shareholder’s individual share of the corporation’s income, deductions, credits, and other tax items. Shareholders use this information to complete their individual Form 1040.  W-2 Salary, Distributions, and Form 1040 (The Owner’s Perspective) If you own and work for an S corp, you must