Reserve Requirements for Depository Institutions (12 C.F.R. 204, Regulation D) is a Federal Reserve regulation which sets out reserve requirements for banks in the United States.
It also limits the number of preauthorized withdrawals and transfers from a savings account or money market account.
In consumer banking, "Regulation D" often refers to §204.2(d)(2) of the regulation, which places a limit of six withdrawals or outgoing transfers per month from savings or money market accounts via several transaction methods. Transactions counted against the limit include "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." Transactions not counted against the limit include "mail, messenger or in person or when such withdrawals are made by telephone (via check mailed to the depositor)."
The regulation was amended in 2009 to allow greater freedom for the depositor: beforehand, the limit was six withdrawals per month if the funds remained within the same institution (e.g., transfer to checking), but was only three drafts where the funds left the institution (e.g., check, ACH, or card based purchase).
The number of deposits or incoming transfers into savings or money market accounts is not limited.
Regulation D does not emplace the six-time transfer limit on outbound savings or money market account transactions initiated in person, via messenger or mail; over-the-counter (OTC) withdrawals and transfers, ATM withdrawals and transfers, or installment loan repayments.