We do not believe that advance notice is required if closing a branch on a Sunday, though it is a best practice to provide some sort of customer notice. The Illinois Promissory Note and Bank Holiday Act governs bank closings, and it sets default bank holidays as being noon onwards on Saturdays and any other holidays listed in the law. In addition, our understanding is that the IDFPR treats Sundays as legal holidays — see the IDFPR’s annual bank holiday schedule, which states that “banks are authorized to close at 12:00 noon on each Saturday and all day on Sunday.”
We recommend checking your account agreements to ensure that they do not contain any customer notification requirements for changes in banking days. It also may be prudent to provide advance notice of the changes in hours to your primary regulators, even if not required. We recommend updating any advertising, listings and information related to the branch to reflect the change as well.