Allocate a 1095-A to a Non-Dependent Adult Child: The 99% Split.

A software consultant in Utah County buys a family plan on the marketplace because his S corp has no group coverage. Household income is $410,000, so the marketplace pays him nothing. His 23-year-old son is on the same policy, coaches part time at a climbing gym, and made $24,000. When you allocate a 1095-A to a non-dependent adult child, that child claims a premium tax credit computed against the whole family's benchmark premium and his own small income. In 2026 the number on the son's return is $26,285.

The Form 1095-A shows one name in Part I and everyone covered in Part II. Nothing on it says who claims what. Treas. Reg. §1.36B-4(b) requires an allocation whenever a single qualified health plan covers people in more than one tax family, and Part IV of Form 8962 is where the split gets reported. The instructions to Form 8962 call this Allocation Situation 4, other situations where a policy is shared between two tax families, and the rule is short: the two taxpayers may agree on any allocation between them.

Three percentages go on the form, in columns (e), (f), and (g): the enrollment premium, the applicable second lowest cost silver plan (SLCSP) premium, and the advance credit. They are entered as decimals, they have to match each other, and the two returns together have to total 100%. Situation 4 carries no reasonableness standard and no test tied to who paid the insurer. The only fallback is a headcount default for parties who cannot agree.

This is where most of these plans die. Section 36B(c)(1)(D) denies the credit to any individual with respect to whom a deduction under §151 is allowable to another taxpayer. Allowable, not claimed. Leaving your son off your return does not make him eligible if you could have put him on it.

So run §152 first. A 23-year-old is not a qualifying child unless he is a full-time student, and even then only if he did not provide over half of his own support. Fail that and he is a qualifying relative only if his gross income is under the §152(d)(1)(B) exemption amount, which Rev. Proc. 2025-32 sets at $5,300 for 2026. A son earning $24,000 fails both, which makes him his own tax family. The $500 credit for other dependents under §24(h)(4) is what people worry about losing, and it is not on the table: a child who still qualifies for it cannot claim the premium tax credit at all.

The size comes from a mismatch built into §36B. The benchmark is the second lowest cost silver plan covering everyone on the policy, three people here. The contribution is a percentage of one person's household income, from the table in Rev. Proc. 2025-25, which for 2026 runs from 2.10% up to 9.96%. The credit is the benchmark less that contribution, capped at the premiums allocated to you. Point 99% of a three-person benchmark at a one-person tax family and the cap rarely binds.

The allocation is not the aggressive part. The size of the number comes from the statute, the IRS has published nothing narrowing Allocation Situation 4, and the form is built to accept it.

You are allowed to allocate 100%. The problem is filing it. A Form 8962 carrying a shared policy allocation with zero premiums, zero benchmark, and zero advance payments trips e-file reject F8962-063, which wants at least one non-zero amount on the form, so the return goes on paper. Holding back 1% keeps the 1095-A matched to a filed 8962 and heads off a Letter 12C. On a $28,800 policy that 1% is $288 of premium and $276 of benchmark, worth no credit and no repayment at $410,000 of income.

• –Medicaid. Under §36B(c)(2)(B) there is no credit for a month the child is eligible for government-sponsored minimum essential coverage, and Treas. Reg. §1.36B-2(c)(2) makes eligibility enough without enrollment. In an expansion state, Utah included, that line is 138% of the poverty line, $21,597 for one person. A son at $18,000 gets nothing.
• –Income under 100% of the poverty line, $15,650 for one person. Treas. Reg. §1.36B-2(b)(6) saves a taxpayer who lands below 100% only if the Exchange estimated at least 100% and authorized advance payments. A family that took no advance credit has no safe harbor.
• –A blank column B. Marketplaces routinely report a zero benchmark when nobody on the policy took an advance credit. Pull the real SLCSP from the health coverage tax tool at HealthCare.gov. Entering the zero computes a credit of zero.
• –Mismatched returns. Both returns carry the same three percentages for the same months, and the IRS matches them. Get the agreement in writing before either return is filed.

The allocation does double duty for parents who took advance credit and then closed the books above 400% of the poverty line. Section 71305 of the One Big Beautiful Bill Act repealed the repayment caps in §36B(f)(2)(B) for tax years beginning after 2025, so they hand back every dollar instead of stopping at $3,250, a problem I worked through in excess premium tax credit repayment in 2026. Allocating 99% to the son moves that repayment onto a return that earns the credit instead.

One piece to model first. A self-employed parent deducts premiums for a child under 27 whether or not the child is a dependent, under §162(l)(1)(D). Treas. Reg. §1.162(l)-1 caps that deduction at the specified premiums less the premium tax credit attributable to them, and whether a credit claimed on the child's own return counts against the parent has no published answer. At a 37% rate a $28,800 deduction is worth $10,656, so this sizes the win rather than deciding it. The same coordination appears in S corp owner health insurance on the W-2.