The grantor reports the real estate sale and claims the withholding on their tax return. Complete Form 593 using the grantor's information.To claim the withholding credit you must file a California tax return. Report the sale or transfer as required. The percentage of withholding may differ for entities. The seller is to complete and certify the optional gain on sale withholding amount on FTB. California Withholding Tax at Escrow Closing. When you sell a home in California, you must complete Franchise Tax Board (FTB) form 593. " It is not an additional tax on the sale of the real estate. If your paychecks seem small and you get a big tax refund every year, you might want to re-fill out a new W-4 and a new California state income tax DE-4 Form.