Self-employed health insurance deduction leaves out the Medicare premiums the model computes (26 U.S.C. 162(l))

What the model does

The self-employed health insurance deduction counts only the direct premium input, so Medicare premiums the model itself computes never reach it.

self_employed_health_insurance_premiums.py sets defined_for = "is_self_employed" and adds = ["health_insurance_premiums"], and nothing else.
The model computes medicare_part_b_premium for every enrollee: the gross premium with any IRMAA, less Medicare Savings Program coverage (medicare_part_b_premium.py, gross_medicare_part_b_premium.py).
medical_expense_health_insurance_premiums.py already adds that premium for enrollees when the direct input is zero (lines 21-28). No formula passes it to the self-employed deduction.
medicare_part_b_premiums_reported exists as an input, but no formula reads it.
The comment in health_insurance_premiums.py says survey data put premiums in the direct input "only for self-employed people under 65 without employer-sponsored coverage". So in survey data, every self-employed Medicare enrollee gets no deduction for Medicare premiums.

26 USC 162(l)(1) allows a deduction for amounts paid for insurance that constitutes medical care for the taxpayer, the spouse, dependents and children under 27.
The Form 7206 instructions say that Medicare premiums a person voluntarily pays for insurance in their own name "can be used to figure the deduction".
The earned-income limit in 162(l)(2)(A) still applies, as does the employer-plan rule in 162(l)(2)(B). Medicare isn't an employer plan.

A single filer in Texas, age 67, in 2026: Schedule C profit $60,000, is_self_employed true, and no other income or premium inputs.

The model enrolls them in Medicare and computes a Part B premium of $2,434.80 (12 × $202.90), with no Savings Program coverage at this income.
Half of SE tax: 60,000 × 0.9235 × 0.153 / 2 = 4,238.865. The model gives 4,238.8647.
Law: the deduction is min(2,434.80, 60,000 − 4,238.865) = $2,434.80, so AGI is 60,000 − 4,238.865 − 2,434.80 = $53,326.335.
Model: self_employed_health_insurance_premiums is 0 and so is the deduction, so AGI is $55,761.1367. Meanwhile medical_expense_health_insurance_premiums is $2,434.80, so the model counts the same premium as a medical expense.

These model values come from a run at 035a1570. Main's formula hasn't changed since #10046 (61fa3e1).

Add the enrollee's modeled Medicare premiums to self_employed_health_insurance_premiums when the direct input is zero, as medical_expense_health_insurance_premiums already does.
Keep the non-Medicare decomposed input (health_insurance_premiums_without_medicare_part_b) out of it for now. Its own comment says most of it is paid by people with employer coverage, whom 162(l)(2)(B) excludes. Exclude employer-plan-eligible premiums from the self-employed health insurance deduction #10122 handles those months.
self_employed_health_insurance_ald_excluded_premiums already removes the deducted amount from the medical expense premiums, so the premium won't count twice.
Part D premiums and Medigap premiums qualify too, but the model has no inputs for them (see Atomic inputs: one fact, one input — eliminate arbitration between redundant input variables #9275 on premium inputs).

🤖 Generated with Claude Code