Banks started handing over the information in accordance with an agreement between the United States and Canada that came into effect last year.
But what does the agreement under the Foreign Account Tax Compliance Act (FATCA) really mean for dual citizens? Here’s what you need to know:
What is FATCA?
On July 1, 2014, Canadian banks began searching for clients who are U.S. citizens under FATCA. As of Canada Day this year, Canadian banks were able to begin handing that information over to the CRA.
With the new agreement in place, banking clients must now prove they’re not American, or their information will be passed on to the CRA, who will then give it to the IRS.
The intergovernmental agreement aims to improve tax compliance of U.S. citizens, according to Canada's Department of Finance.

Why are Canadian banks agreeing to do this?
They don't really have a choice.
U.S. citizens must file tax returns to the United States, no matter where they live, according to the Canadian Bankers Association.
Under the new agreement, Canadian banks must tell the United States if any Americans aren't filing their returns.
The U.S. believes their citizenship has value, said Steven Flynn, a tax lawyer from Vancouver, B.C. And he means that literally.
"The United States is probably the only major country in the world that will tax its citizens on their worldwide income," Flynn told "It catches a lot of people."

Will banks be sending my information to the IRS?
That depends on whether you’re a U.S. citizen or not, and don't be quick to assume you aren't.
According to the U.S. Citizenship and Immigration Services, a person who has an American parent automatically becomes a U.S. citizen at birth no matter where they are born, said Greg Boos, U.S. immigration attorney in Bellingham, Wash. This has left some Canadians unaware that they're dual citizens, he said.
But if you discover you are an American and the banks find out, your information will be sent to the CRA, and the IRS may give you a call next year.
If Americans fail to report their income to the IRS, Flynn said that they could face penaltiesranging from $1,000 to $100,000 per violation.
U.S. tax return going in the mail slot
A woman drops her federal tax return in the mail slot at a post office in Palo Alto, Calif. on April 15, 2008. (AP / Paul Sakuma)
What if I don't want my U.S. citizenship?
You're not alone. In the past few years, the number of American-Canadians giving up their citizenship has risen from 400 people per year to about 5,000, Flynn said.
Canadian citizens who want to give up, orrenounce, their U.S. citizenship must have all their taxes up to date first, Boos said.
They can then make an appointment to renounce at a U.S. consulate, but the appointment wouldn’t be for another six months, he said.
In response to this increase, the U.S. Department of State's renunciation fee increased by five times from $450 to $2,350 last year, Boos said.
"So many people are coming into the United States to renounce their U.S. citizenship that they now have to make some money off of it because they're dedicating a lot of resources to it," he said.
But there is another option.
Those wishing to relinquishing their U.S. citizenship must prove they have committed an "expatriating act," Boos said, which includes accepting a foreign (in this case, Canadian) government job, joining the Canadian Armed Forces or becoming a naturalized citizen of Canada. This last act means a person is over 18 years old and has lived in Canada as a permanent resident for at least 1,460 days during the last six years, according toCitizenship and Immigration Canada.

Are there other issues dual citizens should be aware of?
The issue of what it means to be a U.S.-Canadian or dual citizenship has been in the headlines across Canada recently with theapproval of Bill C-24 last month.
Under the law, Canadians who have -- or are eligible for -- citizenship in another country can have their Canadian citizenship stripped if they are convicted of certain crimes including fraud to obtain citizenship and terrorism offences.
A number of human rights and immigration groups came out against the bill, includingAmnesty International that said the bill violated Canada's charter.

So what should I do now?
Before walking into a consulate and getting rid of their U.S. citizenship, both Boos and Flynn recommend dual citizens meet with a U.S. tax consultant.
Each situation is different, and a consultant will be able to explain whether the IRS will be looking for your tax return in 2016.
"It can be a very scary thing," Flynn said. "But FATCA is forcing people to realize that they don’t have to be a U.S. citizen anymore."