The issue date is the date on which a bond or other financial security is initially issued and made available for purchase by investors. It marks the starting point of the bond's life cycle, from the time it is first offered to the public or sold to institutional investors. The issue date is when the issuer raises capital by selling the bond to investors, and it is typically specified in the bond's prospectus or offering documents.

For investors, the issue date is important as it establishes the beginning of the bond's term and determines key dates such as the maturity date, coupon payment schedule, and other terms of the bond.