National Medical Support Notice (NMSN): Deadlines and Withholding

When a National Medical Support Notice arrives, employer obligations kick in immediately: complete and return Part A within 20 business days, forward Part B to your health plan administrator if dependent coverage is available for the employee, enroll the named children once the administrator qualifies the notice, withhold the premiums from the employee’s pay within federal limits, and keep that withholding in place until you receive written evidence that one of three specific ending conditions has been met. The NMSN is a standardized federal form that state child support agencies use to enforce medical support orders, and once your plan administrator confirms it meets federal criteria it carries the weight of a court order.

The 20-Business-Day Part A Response

The NMSN packet arrives in two parts. Part A is directed at you as the employer and must be completed and returned to the issuing child support agency within 20 business days of the notice date.¹ Two questions drive your response: is this person actually your employee, and is dependent health coverage available to them?

Part A uses checkboxes for the common scenarios. Confirm whether the named employee currently works for you, whether the company offers dependent coverage for that position, and whether the employee is already enrolled. If the employee has been terminated, is not eligible for benefits, or you simply do not offer dependent coverage, check the appropriate box, complete Part A, and send it back. Nothing more is required in those cases.

If dependent coverage is available, you must forward Part B of the packet to the plan administrator within the same 20-business-day window.² The administrator might be your internal benefits department, a third-party administrator, or a labor union’s health and welfare fund. Record the forwarding date on Part A, and where it helps the administrator decide which plans the children can actually be enrolled in, include information about how much of the employee’s earnings are available for premium withholding.¹

If the Employee Is Still in a Waiting Period

Not-yet-eligible is not the same as unavailable. If the employee hasn’t finished a benefits waiting period, do not send Part A back marked “not available.” Complete the section of Part A that tells the agency when the waiting period ends or what condition must be met, such as a required number of hours worked. When the waiting period expires, the plan administrator must process the enrollment, and you are responsible for letting the plan administrator know the employee has become eligible.³

Withholding Limits: What You Can Actually Deduct

The Consumer Credit Protection Act caps how much can be withheld from an employee’s pay for support obligations. Start with disposable earnings, which means gross pay minus only the deductions required by law: federal, state, and local income taxes, the employee’s share of Social Security and Medicare, and any legally mandated retirement contributions. Voluntary items like union dues, 401(k) contributions, and existing health insurance premiums do not reduce disposable earnings for this calculation.⁴

The federal caps applied to that disposable earnings figure are:⁵

50% if the employee is supporting a current spouse or another dependent child
55% in that same situation when the employee is more than 12 weeks behind on support
60% if the employee is not supporting another spouse or child
65% in that situation with arrears exceeding 12 weeks

These caps cover the total of all support-related withholding combined: cash child support, spousal support, and the health insurance premium. If adding the premium would push the total past the applicable cap, you cannot proceed with enrollment on your own. Notify the issuing agency on Part A that the withholding limits prevent enrollment.⁶ Some states set lower caps than the federal limits, so check the law of the state where the employee works.

When a Cash Support Order Is Already in Place

An employee might already have a cash child support withholding in place when the NMSN arrives. If disposable earnings are not enough to cover both the existing cash support and the new premium without breaching the CCPA cap, you cannot pick which one to honor. Federal regulations require you to follow the prioritization rules of the state where the employee works to decide whether cash support or medical support takes precedence.⁶ If the state’s priority scheme does not allow the health premium to be withheld first, complete the appropriate section of Part A and notify the agency. The agency then decides whether to modify the underlying order or pursue other coverage.

What the Plan Administrator Does With Part B

Part B, formally the Medical Support Notice to Plan Administrator, shifts responsibility to whoever administers the health plan. The plan administrator has 40 business days from the date of the NMSN to review it, determine whether it qualifies as a Qualified Medical Child Support Order, and return Part B to the issuing agency.⁷

Once the notice is qualified, the children named in it have a legal right to enrollment in the group health plan, and the plan must enroll them without regard to open enrollment restrictions. An NMSN arriving in June triggers an immediate enrollment obligation even if open enrollment does not start until November. The administrator identifies which plans the children can be enrolled in, provides plan identification numbers, lists effective dates, and documents the type of coverage. Enrollment forms and the Summary Plan Description go to the custodial parent or the state agency so the coverage can actually be used. If the administrator decides the notice does not qualify, they must give specific reasons on Part B and send copies of that determination to the issuing agency, the noncustodial parent, the custodial parent, and the children.

Union and Multi-Employer Plans

When benefits come through a multi-employer plan or a union health and welfare fund, you still bear the initial responsibility. Forward Part B to the union or trust fund acting as plan administrator and record the forwarding date on Part A.¹ Cases frequently stall here in practice. Including information about the employee’s available earnings when you forward Part B helps the union administrator determine feasibility without circling back for more data.

If the Employee Disputes the Notice

An employee who believes the NMSN contains a factual error, such as being misidentified as the obligor, can contest the withholding. Your obligation does not pause while they do. Federal regulations require you to continue withholding and transmitting payments until the issuing agency sends explicit written notice to stop.² Direct the employee to contact the issuing agency at the address and phone number on the notice.¹ The instinct to pause everything until the employee sorts it out is the wrong one; doing so violates your legal duties and carries the same exposure as ignoring the notice.

Notifying the Employee and Using e-NMSN

After enrollment, notify the employee that premium withholding will begin. They need to understand why take-home pay is changing and how their child can access the benefits. Keep a record of the notification in case a dispute arises later.

You can return completed forms by mail, but the Office of Child Support Enforcement also offers an electronic NMSN system that lets agencies and employers exchange notices electronically. You can complete fillable PDF versions of Parts A and B that are picked up and delivered to the issuing agency, or integrate your own payroll system for automated processing.⁸ Electronic processing is faster and creates a reliable audit trail.

When Withholding Ends

Once premium withholding starts, it does not stop until one of three specific things happens:¹

You receive satisfactory written evidence that the underlying court or administrative child support order is no longer in effect, and the employee does not want to keep the coverage voluntarily.
You receive written evidence that the children are enrolled, or will be enrolled, in comparable coverage that takes effect no later than the date they would be disenrolled from the current plan.
The employer eliminates dependent health coverage for all employees.

A verbal request from the employee or the custodial parent is not enough. Get written documentation before stopping withholding or disenrolling the children. Prematurely ending coverage carries the same liability as never enrolling them.

Termination of Employment and COBRA

When an employee subject to an NMSN leaves the company, promptly notify the issuing child support agency. The simplest method is sending a copy of Part A with the termination box checked and, if you know it, information about the former employee’s new employer, which helps the agency transfer the medical support obligation quickly.¹

A child enrolled in a group health plan under a QMCSO is treated as a qualified beneficiary for COBRA purposes, with the right to elect COBRA continuation coverage if coverage is lost because of a qualifying event like the employee’s termination. If neither the employee nor the child elects COBRA, or the COBRA period expires, the plan can discontinue coverage for the child.⁷ Make sure the COBRA election notice reaches the custodial parent or whoever handles the child’s coverage decisions, not just the departing employee.

Penalties for Ignoring the Notice

The NMSN itself warns that employers “may be subject to sanctions or penalties imposed under State law and/or ERISA” for failing to withhold income, failing to transmit withheld amounts to the plan, or retaliating against an employee because of medical child support withholding.⁷ On the federal side, ERISA authorizes civil enforcement actions by states to compel compliance with a QMCSO, and participants and beneficiaries can seek equitable relief that courts have used to order enrollment and recover benefits that should have been provided. Attorney’s fees may be awarded to the prevailing party.⁹

State penalties vary. State child support enforcement agencies can impose fines for failing to respond to or comply with an NMSN, and some states allow the custodial parent or the agency to hold the employer liable for medical expenses the child incurred during the period coverage should have been in place. That last exposure is the one that hurts: the cost of a single emergency room visit or ongoing treatment for an uninsured child dwarfs whatever staff time it takes to process the notice properly and start withholding premiums.

1
Administration for Children and Families. National Medical Support Notice Part A Instructions
2
eCFR. 45 CFR 303.32 – National Medical Support Notice
3
Administration for Children and Families. National Medical Support Notice
4
U.S. Department of Labor. Fact Sheet 30 – Wage Garnishment Protections of the Consumer Credit Protection Act
5
Office of the Law Revision Counsel. 15 USC 1673 – Restriction on Garnishment
6
Administration for Children and Families. Medical Support
7
U.S. Department of Labor. Qualified Medical Child Support Orders
8
Administration for Children and Families. e-NMSN
9
Office of the Law Revision Counsel. 29 USC 1132 – Civil Enforcement