OATs are government bonds issued by Agence France Trésor (French Treasury), generally by auction according to an annual calendar published in advance. These fungible securities are issued with maturities

Maturity (finance)

In finance, maturity or maturity date refers to the final payment date of a loan or other financial instrument, at which point the principal is due to be paid....

of seven to 50 years, and have become the method of choice for placing the French government’s long-term debt. .