The CSIS is in fact equivalent to the United States' CIA, which I think you meant to write.
The U.S. Secret Service has two major responsibilities
* protecting national leaders the like President, Vice President, presidential candidates, visiting foreign dignitaries, and their families
* investigating crimes of fraud and counterfeiting that affect the financial system of the United States
(Why? The Secret Service used to be an agency of the Treasury, and didn't start protecting the President until 1901.)
In Canada, the RCMP is also responsible for protecting major leaders like the Monarch, the Prime Minister, and the Governor General. And, as far as I can tell, the RCMP is also responsible for investigating financial crimes, so it looks like the RCMP is the answer to your question.