**The 87.5% implied probability that Trump will not cut the corporate tax rate before 2027 reflects the enactment and effects of the One Big Beautiful Bill Act (OBBBA), signed July 4, 2025.** That reconciliation package permanently extended the 21% corporate rate from the 2017 TCJA while adding business provisions such as permanent 100% bonus depreciation for qualified property, restored immediate R&D expensing, and expanded interest deductibility limits. Proposals to lower the rate to 15% for domestic manufacturing were discussed in earlier House versions and the 2024 campaign platform but were omitted from the final enacted text. As of August 2026, no subsequent legislation or executive action has altered the statutory rate. The 2026 legislative calendar, narrow congressional margins, and focus on implementation of the prior bill plus other priorities have limited appetite for another major tax reconciliation package before the 2027 deadline. Traders view the combination of a recently locked-in rate and the procedural and political hurdles to further rate reduction as the dominant drivers of the current market pricing.