Mortgage Interest Deduction 2018-2025 (TCJA)

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Reference

policyengine-us/policyengine_us/parameters/gov/irs/deductions/itemized/interest/mortgage/cap.yaml

Lines 1 to 21 in deb7c0c

	description: IRS limits the total home mortgage interest deduction to this amount, based on filing status.
	SINGLE:
	2018-01-01: 1_000_000
	JOINT:
	2018-01-01: 1_000_000
	SEPARATE:
	2018-01-01: 500_000
	HEAD_OF_HOUSEHOLD:
	2018-01-01: 1_000_000
	SURVIVING_SPOUSE:
	2018-01-01: 1_000_000
	metadata:
	breakdown: filing_status
	unit: currency-USD
	label: IRS home mortgage interest deduction amount cap
	reference:
	# Hawaii applies this AGI threshold in the state itemized deductions computation
	- title: Hawaii Income Tax Law, Chapter 235, Section 235-2.4, (j)(3)
	href: https://files.hawaii.gov/tax/legal/hrs/hrs_235.pdf#page=10
	- title: 26 U.S. Code § 163 - Interest, (h)(3)(F)
	href: https://www.law.cornell.edu/uscode/text/26/163

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Closing as implemented. parameters/gov/irs/deductions/itemized/interest/mortgage/cap.yaml applies the TCJA caps of $750,000 (single/joint/HoH/surviving spouse) and $375,000 (separate) from 2018-01-01 (merged in #5129). The structural federal mortgage interest deduction was further formalized in #7875, and OBBB extended the TCJA limits beyond 2025 as reflected in the current parameter references.