What appears to have happened is that Citibank is taking care of a relatively obscure requirement affecting checking accounts that are classified as NOW accounts or Automatic Transfer Service accounts. The law and regulations require that a bank reserve the right to require seven days' notice of withdrawal from such accounts. In practice, however, banks don't exercise that right, since that would alter significantly how customers use those types of checking accounts. Citibank would be a much more reliable source of information for your question.
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