Connecticut corporate research and development credit
Tax credit
Agency: Connecticut Department of Revenue Services. Agency source
This directory is not tax advice. Confirm eligibility, tax-year rules, deadlines and filing requirements with a tax professional.
Check program requirements [Connecticut 2025 Form CT-1120 RDC instructions]
- Who qualifies
- Corporation Business Tax filers conducting qualifying Connecticut research. The small-business calculation requires prior-year gross income no greater than $100 million and satisfaction of related-party restrictions. [Connecticut 2025 Form CT-1120 RDC instructions]
- What it’s worth
- Tentative credit of 6% for qualified small businesses, subject to annual-use limits. Eligible businesses with gross income at most $70 million and no corporation tax liability may exchange credits at 65% or 90%, subject to eligibility restrictions. [Connecticut 2025 Form CT-1120 RDC instructions]
- How to claim
- Use CT-1120 RDC and CT-1120K. For an eligible exchange, file CT-1120 XCH separately with supporting schedules at the same time as the corporation return. [Connecticut 2025 Form CT-1120 RDC instructions]
- Deadlines and application windows
- Claim with the applicable tax-year forms. Current-year exchange limits apply; unused credits earned from 2021 may carry forward 15 income years. [Connecticut 2025 Form CT-1120 RDC instructions]
Amounts are subject to the conditions in each listing. A source review does not mean applications are open or that a business qualifies.
Official sources
Listing reviewed