Cal. COM § 11209

(a) Subject to subdivision (d), a receiving bank other than the beneficiary’s bank accepts a payment order when it executes the order.

(b) Subject to subdivisions (c) and (d), a beneficiary’s bank accepts a payment order at the earliest of the following times:

(1) When the bank (i) pays the beneficiary as stated in subdivision (a) or (b) of Section 11405, or (ii) notifies the beneficiary of receipt of the order or that the account of the beneficiary has been credited with respect to the order unless the notice indicates that the bank is rejecting the order or that funds with respect to the order may not be withdrawn or used until receipt of payment from the sender of the order.

(2) When the bank receives payment of the entire amount of the sender’s order pursuant to paragraph (1) or (2) of subdivision (a) of Section 11403.

(3) The opening of the next funds-transfer business day of the bank following the payment date of the order if, at that time, the amount of the sender’s order is fully covered by a withdrawable credit balance in an authorized account of the sender or the bank has otherwise received full payment from the sender, unless the order was rejected before that time or is rejected within (i) one hour after that time, or (ii) one hour after the opening of the next business day of the sender following the payment date if that time is later. If notice of rejection is received by the sender after the payment date and the authorized account of the sender does not bear interest, the bank is obliged to pay interest to the sender on the amount of the order for the number of days elapsing after the payment date to the day the sender receives notice or learns that the order was not accepted, counting that day as an elapsed day. If the withdrawable credit balance during that period falls below the amount of the order, the amount of interest payable is reduced accordingly.

(c) Acceptance of a payment order cannot occur before the order is received by the receiving bank. Acceptance does not occur under paragraph (2) or (3) of subdivision (b) if the beneficiary of the payment order does not have an account with the receiving bank, the account has been closed, or the receiving bank is not permitted by law to receive credits for the beneficiary’s account.

(d) A payment order issued to the originator’s bank cannot be accepted until the payment date if the bank is the beneficiary’s bank, or the execution date if the bank is not the beneficiary’s bank. If the originator’s bank executes the originator’s payment order before the execution date or pays the beneficiary of the originator’s payment order before the payment date and the payment order is subsequently canceled pursuant to subdivision (b) of Section 11211, the bank may recover from the beneficiary any payment received to the extent allowed by the law governing mistake and restitution.