Research and experimental expenditure
For tax years beginning after 31 December 2024, domestic research expenditure is deductible; foreign research expenditure is amortized over 15 years. Amounts capitalized for 2022–2024 are subject to transition rules and elections.
IRC §174A, §174 (P.L. 119-21 §70302); Rev. Proc. 2025-28
Advance payments
An accrual-method taxpayer may defer advance payments to the following year to the extent deferred in its applicable financial statements, but no further.
IRC §451(c); Treas. Reg. §1.451-8
Stock compensation deduction
The deduction generally follows the employee’s income inclusion rather than the book expense, producing a book-to-tax difference; incentive stock options generally produce no deduction absent a disqualifying disposition.
IRC §83(h); §421
Research credit and payroll offset
A qualified small business may elect to apply up to $500,000 of research credit against employer payroll tax.
IRC §41(h); Form 6765
Qualified small business stock and Delaware franchise tax
Gross-asset tests at stock issuance affect §1202 eligibility; Delaware franchise tax may be computed under two methods, and the lesser is payable.
IRC §1202; 8 Del. C. §503