External transfers set up before 2pm on a business day will post the next business day.  External transfers set up after 2pm on a business day will post two business days later.

For example:
External loan payment set up on Monday before 2pm CST – loan payment will post on Tuesday
External loan payment set up on Monday after 2pm CST – loan payment will post on Wednesday
External loan payment set up on Monday before 2pm CST, but Tuesday is a holiday – loan payment will post on Wednesday
External loan payment set up on Monday after 2pm CST, but Tuesday is a holiday – loan payment will post on Thursday due to the holiday