Missouri requires corporations conducting business or earning income in the state to comply with corporate income and franchise tax rules. C corporations are taxed at 4% and must file annual returns. If their assets exceed USD 10 million, franchise tax filing is also required. Estimated payments, extensions, penalties, and interest provisions are in place to ensure compliance.
S corporations and partnerships, including LLCs and LLPs, also face filing obligations. While partnerships and LLCs are not taxed at the entity level, income is passed on to owners, who must report it individually. Each entity type has its own filing requirements, deadlines, and penalties, with extensions available but limited to filing only.
This blog explains the corporate, S corporation, and partnership taxation framework in Missouri, helping businesses and individuals understand their obligations and avoid penalties.
C Corporation Tax
C corporations that conduct business in Missouri or have income sourced from the state are required to file a Missouri Corporate Income Tax Return (Form MO-1120). This return reports income, deductions, credits, and calculates tax liability.
Corporate Income Tax Rate:
- Missouri imposes a flat rate of 4% on corporate income.
Franchise Tax:
- Corporations with assets or apportioned assets exceeding USD 10,000,000 must file Schedule MO-FT along with Form MO-1120, balance sheet, and supporting schedules.
- If assets are USD 10,000,000 or less, no franchise tax payment is necessary.
Due Date:
- Returns must be filed by the 15th day of the 4th month following the close of the taxable year.
Extensions:
- If the IRS grants a federal extension (Form 7004), the Missouri return is automatically extended for the same period.
- The federal extension must be attached to Form MO-1120 when filed.
Interest and Penalty:
- Interest: 6% per annum on delinquent taxes from the due date until paid.
- Late filing penalty: 5% per month, capped at 25% of unpaid tax.
- Late payment penalty: 5% of unpaid tax if not paid by the original due date (unless 90% of the tax is paid by then and the balance cleared by the extended due date).
Estimated Tax Payments:
- Required if a corporation’s estimated Missouri tax liability is USD 250 or more.
- Corporations must declare estimated taxes using Form MO-1120ES.
S Corporation Tax
S corporations in Missouri must file an annual Missouri S Corporation Income Tax Return (Form MO-1120S). This form reports the income, deductions, and credits of the entity.
Franchise Tax Requirement:
- If assets or apportioned assets exceed USD 10,000,000, the S corporation must also file Schedule MO-FT with Form MO-1120S, along with a balance sheet and supporting schedules.
- If assets are equal to or less than USD 10,000,000, no franchise tax payment is due.
Due Date:
- The return and any franchise tax are due by the 15th day of the 4th month after the end of the taxable year.
Extensions:
- An extension of time granted for the federal return (Form 7004) automatically extends the Missouri return deadline for the same period.
- A copy of the federal extension must be attached when filing.
Note: Estimated tax payment rules, interest, and penalties are the same as for C corporations.
Partnership LLP & LLC Tax
Partnerships, LLPs, and LLCs in Missouri are generally not subject to entity-level tax. Instead, profits or losses flow through to the partners or members, who report their share on individual tax returns.
Form Used:
- Partnerships file Form MO-1065 – Missouri Partnership Return of Income.
- Each member reports their share of income on their individual return using Form MO-1040.
Due Date:
- Partnership returns must be filed by the 15th day of the 4th month following the close of the taxable year.
Extensions:
- Partnerships can file Form MO-60 – Application for Extension of Time to File.
- This provides five additional months to file, but does not extend the deadline for payment of taxes owed.
Estimated Tax Payments:
- Partnerships themselves do not make estimated payments.
- Instead, individual partners must make estimated tax payments on their share of income using Form MO-1040ES.
- Estimated payments are made in four installments: 15th day of the 4th, 6th, 9th, and 1st months of the next tax year.
Interest and Penalties:
- Interest: 6% per annum on unpaid taxes.
- Late filing penalty: 5% per month, up to 25% of unpaid tax.
- Late payment penalty: Additional 5% on unpaid balances if not settled by the due date.
These provisions ensure that while partnerships are not taxed directly, individual partners are still held accountable for timely payment of taxes.
Conclusion
Missouri’s tax system places clear obligations on corporations, S corporations, and partnerships/LLCs.
- C corporations: Must file Form MO-1120, pay a 4% income tax, and file franchise tax forms if assets exceed USD 10,000,000.
- S corporations: File Form MO-1120S, with franchise tax rules identical to those for C corporations.
- Partnerships and LLCs: File Form MO-1065 for informational purposes, with income passed on to members for individual reporting.
Across all entity types, estimated payments are required once liability thresholds are met. Interest of 6% per annum and penalties of up to 25% apply for late compliance. Extensions are available for filing, but not for paying taxes due.
Missouri’s approach ensures that businesses of all sizes contribute fairly, while also making clear that compliance is a responsibility shared between entities and their owners. By meeting filing deadlines, tracking asset levels, and making estimated payments on time, businesses can stay compliant and avoid costly penalties.
