You have an extra month to file. Due date: Nov. 15
Beginning with returns due April 15, 2017, C-corporations have an automatic 7-month filing extension. If you are a calendar year filer, your extension return is due Nov. 15. See Tax Bulletin 17-9 for details.
Nonprofits and other entities have a 6-month filing extension.
Reminder: The extension provisions do not apply to payment of any tax due with your return. To avoid penalties, you should have paid at least 90% of your final tax liability by the original due date for filing the return. If you didn’t make a payment or pay enough, we will send you a bill for taxes owed along with penalty and interest.
See Corporation Income Tax – How to File and Pay for filing options.