The SDI withholding rate for 2025 is 1.2 percent. Effective January 1, 2024, all wages are subject to SDI contributions.So there should be no SDI deductions withheld from lump sum payments. This includes lump sum payments for vacation cash out or 401(k) plans. These taxes are also called SDI contributions. When employees fill out information for CASDI on their W2 form, they must enter the dollar amount withheld in Box 14. California State Disability Insurance (CA SDI) is a workerfunded program that provides partial wage replacement when a worker needs to take time off work. California wages are subject to SDI (State Disability Insurance) or VDPI (Voluntary Plan Disability Insurance) withholding up to a specific annual amount. California Residents: If you make no state tax withholding election,. If you look at your paycheck stub (or W-2 Form), you'll see a withholding line item called CA SDI (California State Disability Insurance).