The maturity date for retirement savings bonds is indeterminate and may be different for each bond issued, but shall not exceed the sum of an original maturity period of 20 years and an extended maturity period of 10 years. A retirement savings bond purchased by the IRA custodian on behalf of a participant will mature at the earlier of 30 years from the date the bond is first issued to the custodian on behalf of the participant or when its value reaches $15,000.