The fragile certainty of Bonus Depreciation

Acceleration works until it becomes expectation, and expectation is the one thing the Code never guarantees.

Tax incentives survive when they promise speed.

Policymakers gamble that accelerating deductions will accelerate investment. Taxpayers gamble that the rules will stay still long enough to matter.

History suggests both sides overestimate their control.

Bonus depreciation has always lived in this space. A timing tool is treated as a stimulus. A temporary fix that became a planning staple.

The latest law makes it “permanent” again, but permanence in tax policy is usually a long intermission, not an ending.

The One Big Beautiful Bill Act reinstates 100% bonus depreciation for qualifying property as of January 20, 2025.

The phase-down enacted under the 2017 tax law is gone. In principle, any qualifying asset placed in service after this date returns to full expensing.

In practice, the rules run on older machinery.

Written binding contracts continue to govern eligibility. Construction timing still fixes a project to the rules in place when meaningful work began. The new law also creates a separ…