SB 1429 - Current law requires withholding tax returns to be submitted electronically by employers with at least two hundred fifty employees. Beginning January 1, 2026, this act requires such electronic returns for employers with an amount of employees that meets or exceeds the threshold provided in federal law. This act is substantially similar to HB 1919 (2026) and to a provision in HCS/SB 994 (2026). JOSH NORBERG

2026 Regular Session

Missouri employers meeting the federal threshold must electronically file withholding information returns by Jan 31 each year, using SSA-like formats.

Second Read and Referred S Economic and Workforce Development Committee

Summary of SB 1429 (Session 2026, Missouri)

Purpose and intent

Align Missouri withholding tax return filing with a federally defined threshold for electronic submission.

Repeals and replaces the existing provision governing information returns for withholding with a new standard: beginning January 1, 2026, employers with an amount of employees meeting or exceeding the federal threshold must file withholding information returns electronically.

Key provisions and changes

Repeals existing Section 143.591 and enacts a new Section 143.591 governing information returns for withholding.

Requires electronic filing of withholding tax returns for wages (and related information) paid in the previous tax year by employers that have employees meeting the threshold specified in federal law.

Threshold specifics:

The bill references the threshold as per 26 C.F.R. 301.6011-2 (the federal threshold used for electronic filing requirements).
The bill retains the principle that electronic returns are required for employers with a sufficiently large workforce, aligning with federal standards.

Filing deadline and format:

Electronic submissions must be made by January 31st of the year following the tax year.
Returns must use the same file specifications as the electronic filing formats used for forms filed with the Social Security Administration (SSA).

Waiver provision:

If an employer has been granted a waiver from the federal requirement to file electronically by the IRS, the employer may submit a copy of that approved waiver to the Missouri Director of Revenue, which automatically waives the Missouri electronic filing requirement as well.

Who would be affected

Employers in Missouri who:

Have a number of employees meeting or exceeding the threshold established by the federal rule (as implemented through 26 C.F.R. 301.6011-2).
File withholding wages information and are subject to Missouri withholding reporting requirements.

State agencies and the Missouri Department of Revenue:

Responsible for administering and enforcing electronic filing requirements and processing these returns using SSA-like file formats.

Procedural and timeline aspects

Effective date: Beginning January 1, 2026.

Filing deadline: January 31st of the year following the tax year for which wages were paid.

Submission method: Electronically, using file specifications compatible with SSA electronic filing formats.

Federal waiver alignment: Automatic waiver of Missouri electronic filing if the employer holds IRS-approved federal waiver for electronic filing.

Potential impact and considerations

Administrative burden and cost shift:

Employers currently not filing electronically may need to upgrade systems to meet SSA-style electronic filing specifications.
Large employers will experience continued alignment with federal standards, potentially simplifying cross-agency reporting.

Compliance and enforcement:

The Missouri Department of Revenue will enforce electronic submission thresholds and deadlines; noncompliance could trigger penalties or corrective actions per state law.

Interplay with federal requirements:

Administrative consistency with federal reporting requirements may reduce duplicative processing and facilitate data matching with IRS records.

Note: The bill text indicates alignment with existing structure and similar provisions found in HB 1919 (2026) and HCS/SB 994 (2026).