TORONTO - Canada, which issued its first ultra-long bond in April 2014, is considering more in the future, the government said on Thursday.

Any issuance would be done by reopening that 50-year bond via a modified auction, subject to market conditions, the government said on the Bank of Canada website.

The 2.75 per cent bond, which matures on Dec. 1, 2064, had $3.5 billion outstanding at the end of July. Canada last reopened the bond in November 2014 with a $1 billion issue.

Canada is one of the few leading industrialized nations with an undisputed AAA rating, and its bonds are in high demand.

Ultra-long bonds have a term to maturity of 40 years or more. A 50-year duration for sovereign bonds is not as common as a 30-year, although several Canadian provinces already issue ultra-long bonds.

Earlier this year, U.S. Treasury Secretary Steven Mnuchin said the United States was studying the possibility of issuing 50-year and 100-year bonds. Debt for both Mexico and Ireland has durations of up to a century.