Resources For
Corporations
If you are looking for information on corporations - or incorporating a business - this section of the site will help you find key information you need to understand how Ontario business taxes apply to you.
The ministry offers many convenient services:
- Change of Business Information Service
Notify the Ministry of Government Services, the Ministry of Finance, and the Canada Revenue Agency of updated business information such as address changes or the closing of an account. - Internet Banking Service (IBS)
Corporations can use the online tax payment service, IBS, using their financial institution's website. It enables participating financial institutions' customers to electronically remit corporations tax payments via the Internet. - D-FILE
Corporations can file CT23 and related schedules in an electronic format through D-FILE. The D-FILE package consists of a floppy disk and paper documentation. - Combined Annual Return
For convenience, corporations can file a combined annual return. This form is a combination of the Ministry of Finance CT23 Corporations Tax Return and the Ministry of Government Services Annual Return.
Account maintenance
- Authorizing or Cancelling a Representative
Authorization is required for an individual or firm to deal with the ministry on your behalf. - Amalgamations and Ownership Changes
- Business Start-up and Registration
- Closing Your Business and Tax Account/Dissolving an Inactive Corporation
- Voluntary Disclosure
Individuals and corporations are encouraged to voluntarily approach the ministry to correct any deficiencies or contraventions of tax statutes and benefit programs.
Programs of Interest
- Apprenticeship Training Tax Credit
- Co-operative Education Tax Credit
- Corporations Tax
- Employer Health Tax
- Retail Sales Tax
Audits
Audits ensure taxpayers fulfill their tax obligations in accordance with the laws administered by the ministry, and to inform and educate taxpayers.
You may be chosen for an audit based on a number of reasons, including random and risk-based selection. Audits may also result from an audit under another tax program.
- Corporations Tax Audits
- What to Expect During an Ontario Ministry of Finance Audit
- Objections and Appeals
Events
- Scientific Research & Experimental Development Seminars
- PST - GST/HST Seminars
- Tax Information Forums


