The Federal Reserve requires the financial institution (bank, thrift, or credit union) to hold different amounts of reserves depending on the type of account, demand deposit accounts (checking or share draft) versus savings accounts. The financial institution has lower reserve requirements, and hence lower costs, for a savings account because the savings account is not subject to an immediate withdrawal of the funds. The financial institution may, whenever it chooses, require 7 days written notification of a withdrawal.
http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=4971c78a823bb2d1acc0cb5cff31afd6&rgn=div8&view=text&node=12:2.0.1.1.5.0.2.2&idno=12Title 12: Banks and Banking
PART 204—RESERVE REQUIREMENTS OF DEPOSITORY INSTITUTIONS (REGULATION D)
§ 204.2 Definitions.
(d)(1) Savings deposit means a deposit or account with respect to which the depositor is not required by the deposit contract but may at any time be required by the depository institution to give written notice of an intended withdrawal not less than seven days before withdrawal is made, and that is not payable on a specified date or at the expiration of a specified time after the date of deposit. The term savings deposit includes a regular share account at a credit union and a regular account at a savings and loan association.
(2) The term “savings deposit” also means: A deposit or account, such as an account commonly known as a passbook savings account, a statement savings account, or as a money market deposit account (MMDA), that otherwise meets the requirements of §204.2(d)(1) and from which, under the terms of the deposit contract or by practice of the depository institution, the depositor is permitted or authorized to make no more than six transfers and withdrawals, or a combination of such transfers and withdrawals, per calendar month or statement cycle (or similar period) of at least four weeks, to another account (including a transaction account) of the depositor at the same institution or to a third party by means of a preauthorized or automatic transfer, or telephonic (including data transmission) agreement, order or instruction, or by check, draft, debit card, or similar order made by the depositor and payable to third parties. A preauthorized transfer includes any arrangement by the depository institution to pay a third party from the account of a depositor upon written or oral instruction (including an order received through an automated clearing house (ACH)) or any arrangement by a depository institution to pay a third party from the account of the depositor at a predetermined time or on a fixed schedule. Such an account is not a transaction account by virtue of an arrangement that permits transfers for the purpose of repaying loans and associated expenses at the same depository institution (as originator or servicer) or that permits transfers of funds from this account to another account of the same depositor at the same institution or permits withdrawals (payments directly to the depositor) from the account when such transfers or withdrawals are made by mail, messenger, automated teller machine, or in person or when such withdrawals are made by telephone (via check mailed to the depositor) regardless of the number of such transfers or withdrawals.4
4 In order to ensure that no more than the permitted number of withdrawals or transfers are made, for an account to come within the definition of “savings deposit,” a depository institution must either:
(a) Prevent withdrawals or transfers of funds from this account that are in excess of the limits established by paragraph (d)(2) of this section, or
(b) Adopt procedures to monitor those transfers on an ex post basis and contact customers who exceed the established limits on more than occasional basis. For customers who continue to violate those limits after they have been contacted by the depository institution, the depository institution must either close the account and place the funds in another account that the depositor is eligible to maintain or take away the transfer and draft capacities of the account. An account that authorizes withdrawals or transfers in excess of the permitted number is a transaction account regardless of whether the authorized number of transactions is actually made. For accounts described in paragraph (d)(2) of this section, the institution at its option may use, on a consistent basis, either the date on the check, draft, or similar item, or the date the item is paid in applying the limits imposed by that section.