California Code, Government Code - GOV § 25532

In the event of a sale on a higher oral bid to a purchaser procured by a licensed real estate broker, other than the broker who submitted the highest written proposal, and who is qualified as provided in Section 25527 of this code, the board shall allow a commission on the full amount for which the sale is confirmed.  One-half of the commission on the amount of the highest written proposal shall be paid to the broker who submitted it, and the balance of the commission on the purchase price to the broker who procured the purchaser to whom the sale was confirmed.