H.R. 8600 — To amend the Internal Revenue Code of 1986 to temporarily suspend certain fuel excise taxes for fuel separated during periods in which the national average price of gasoline exceeds $3.99 per gallon, and to prohibit certain credits or deductions for oil and gas companies during such periods.

This section establishes a partial suspension of the excise tax on gasoline, diesel fuel, and kerosene under IRC §4081(a)—and suspends specified oil and gas tax benefits—during any month when the national average price of gasoline exceeds $3.99 per gallon, effective for taxable years beginning after December 31, 2025. Specifically, it (1) reduces the §4081 tax (but not below zero) by 1 cent for each cent of such excess, with transfers from the general fund to the Highway Trust Fund and Leaking Underground Storage Tank Trust Fund (treated as tax receipts under §§9503 and 9508) to offset the revenue loss; (2) suspends immediate expensing of intangible drilling costs under §263(c) (i.e., requires capitalization of such costs paid or incurred by oil and gas companies); (3) disallows the enhanced oil recovery credit under §43 for qualified costs (i.e., up to 15% credit for tertiary recovery methods to extract additional oil); and (4) excludes production from the marginal well production credit under §45I (i.e., up to $3.00 per barrel oil equivalent credit for low-output domestic wells).