sentences:  In March 2013, the Office of the Superintendent of Financial Institutions announced that Canada's six largest banks, the Bank of Montreal, the Bank of Nova Scotia, the Canadian Imperial Bank of Commerce, National Bank of Canada, Royal Bank of Canada and Toronto-Dominion Bank, were too big to fail.Those six banks accounted for 90% of banking assets in Canada at that time.It noted that "the differences among the largest banks are smaller if only domestic assets are considered, and relative importance declines rapidly after the top five banks and after the sixth bank (National)."