CT-990T ES, Estimated Unrelated Business Income Tax Return Payments are due quarterly,  no later than the 15th day of the 3rd, 6th, 9th and 12th  month of the income year ( 3/15, 6/15, 9/15 and 12/15 for calendar year filers).  If the due date falls on a Saturday, Sunday, or legal holiday, the next business day is the due date. To find the form or further instructions, click here.


Pay Electronically: Visit www.ct.gov/TSC to use the Taxpayer Service Center (TSC) to make a direct tax payment. After logging onto the TSC, select the Make Payment Only option and choose a tax type from the drop down box. Using this option authorizes DRS to electronically withdraw from your bank account (checking or savings) a payment on a date you select up to the due date. As a reminder, even if you pay electronically you must still file your return by the due date. Tax not paid on or before the due date will be subject to penalty and interest.