Indiana Code Title 28. Financial Institutions § 28-2-2-1

Sec. 1. Nothing in any law of this state shall in any manner whatsoever affect the validity of or render void or voidable the payment, certification, or acceptance of a check or other negotiable instrument or any other transaction by a bank or trust company in this state, because done or performed during any time other than regular banking hours;  provided that nothing in this section shall be construed to compel any bank or trust company in this state, which by law or custom is entitled to close at noon on any business day or for the whole or any part of any legal holiday, to keep open for the transaction of business or to perform any of the acts or transactions enumerated in this section on any business day after such hour or on any legal holiday, except at its own option.