If you advertise the APY on an outdoor sign, you must include:
- the minimum balance to obtain the APY
- the term of the account
This assumes there are no bonuses involved, and that this isn't a CD subject to the requirements of 230.8(c)(6)(iii) (non-compounding CD with term of more than one year).
Don't forget "Member FDIC" unless the sign is affixed to your bank building.