The agency says the $16.7 billion of Canadian bonds bought by non-resident investors in May is the largest such inflow of funds in three years.
Foreign investment in Canadian equities amounted to $2.1 billion in May, the largest amount since November 2011
Canadian investors purchased $1.3 billion of foreign securities in the month, following a divestment in April.
Canadian investors added $1.7 billion of foreign equities to their holdings, extending an investment pattern that began in January 2011.
But the agency says Canadians also removed $402 million of foreign debt securities from their portfolios in May, largely US government securities.