PRIMARY SOURCES · 50+ AUTHORITIES

Sources cited across the site.

Every page links its claims to a primary source — statute, regulation, revenue procedure, IRS notice, publication, legislation, or judicial decision. The full list of authorities cited site-wide is below, grouped by source type.

Statute (Internal Revenue Code)

IRC §168 — Accelerated Cost Recovery System (MACRS)
IRC §168(k) — Special allowance for certain property (bonus depreciation)
IRC §179 — Election to expense certain depreciable business assets
IRC §263A — Capitalization and inclusion in inventory costs (UNICAP)
IRC §469 — Passive activity losses and credits limited
IRC §481 — Adjustments required by changes in method of accounting
IRC §1031 — Like-kind exchanges of real property
IRC §1245 — Gain from dispositions of certain depreciable property
IRC §1250 — Gain from dispositions of certain depreciable realty
IRC §1411 — Net investment income tax

Treasury Regulations

Treas. Reg. §1.48-1(c) — Definition of section 38 property — the permanence test for personal property classification
Treas. Reg. §1.168(k)-2 — Final regulations on bonus depreciation (TD 9993)
Treas. Reg. §1.179-1 — Election to expense certain depreciable property
Treas. Reg. §1.446-1(e) — Methods of accounting — changes in method
Treas. Reg. §1.469-5T — Material participation tests
Treas. Reg. §1.469-9 — Real estate professional rules (REPS aggregation)
Treas. Reg. §1.1250-1 — Gain from dispositions of section 1250 property

Revenue Procedures

Rev. Proc. 87-56 — Asset class table for MACRS (~150 asset classes)
Rev. Proc. 2015-13 — Master procedures for automatic and non-automatic changes in accounting method
Rev. Proc. 2025-08 — Automatic consent procedures for late §168(k) elections (superseded)
Rev. Proc. 2026-08 — Current automatic consent procedures for late §168(k) elections
Rev. Proc. 2025-32 — Inflation adjustments for 2026 (§179 dollar limit, phase-out)

IRS Notices and Announcements

Notice 2025-17 — Binding-written-contract transition rule for OBBBA §168(k) restoration
Notice 2025-71 — Transition rule for property under binding contract prior to OBBBA enactment
Notice 2026-12 — Placed-in-service date clarification for binding written contracts

IRS Publications

Pub. 527 — Residential Rental Property
Pub. 535 — Business Expenses
Pub. 544 — Sales and Other Dispositions of Assets
Pub. 925 — Passive Activity and At-Risk Rules
Pub. 946 — How to Depreciate Property (2025 edition, OBBBA-incorporated)
Pub. 5653 — Cost Segregation Audit Techniques Guide (8 chapters)

Legislation

Tax Reform Act of 1986 — Established MACRS (replaced ACRS)
PATH Act 2015 — Bonus depreciation extension and modifications
Tax Cuts and Jobs Act 2017 — §13201 (bonus depreciation 2017 reform); §13202 (§179 expansion); §13303 (§1031 limitation to real property)
CARES Act 2020 — §2307 (QIP technical correction restoring 15-year life)
One Big Beautiful Bill Act 2025 (OBBBA) — §70302 (permanent 100% bonus depreciation restoration); §70303 (§179 dollar limit); §70304 (QIP confirmation)

Judicial decisions

Hospital Corporation of America v. Commissioner, 109 T.C. 21 (1997) — Seminal cost segregation case; established the building-component classification framework under MACRS
Whiteco Industries v. Commissioner, 65 T.C. 664 (1975) — Six-factor permanence test for personal property classification

Chief Counsel Advice

CCA 202612008 — QIP eligibility for owner-occupied portions of mixed-use buildings