On Wednesday, August 20, 2025, IIT phone lines will be down for maintenance. However, you can access tax account information or ask a question online.
Additional Details Categories
To view additional details on the Corporate Income Tax, choose from the categories below.
| Tax Base | Insurance Companies / Financial Institutions |
| Nexus and Apportionment | Unitary Business Groups |
| Credits | Filing Requirements |
| Forms & Instructions | FAQs |