From the official interpretation:
1030.4.b(1)(1)2
2. Fixed-rate accounts. For fixed-rate time accounts paying the opening rate until maturity, institutions may disclose the period of time the interest rate will be in effect by stating the maturity date. (See Appendix B,, B-7--Sample Form.) For other fixed-rate accounts, institutions may use a date (“This rate will be in effect through May 4, 1995â€) or a period (“This rate will be in effect for at least 30 daysâ€).
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I hear and I forget. I see and I remember. I do and I understand.--Confucius