California Supplemental Tax Regulations for Databricks RSUs
California Franchise Tax Board (FTB) mandates a 10.23% flat supplemental withholding rate for equity compensation. Because California top marginal rates reach 13.3% (plus 1.1% uncapped CASDI for wage bases), high earners frequently face a substantial 3.0%–4.0% state tax gap on April 15.
California Safe Harbor & Underpayment Penalties
Pay 110% of prior year CA tax or 90% of current year liability to eliminate underpayment penalties.
Employer Stock Plan Specifics: Carta / Shareworks
Databricks pre-IPO equity compensation involves RSUs that trigger tax upon liquidity events or structured tender offers. Knowing your exact supplemental gap ensures you reserve adequate cash when participating in company-sponsored secondary sales.
When vesting at Databricks, Carta / Shareworks calculates automatic sell-to-cover withholding using California's statutory supplemental rate of 10.23% combined with the federal supplemental rate (22% on up to $1M). Because top earners in California reach marginal brackets exceeding these rates, you will face an incremental shortfall on April 15.
Localized CPA & Advisory Referral
Advisor Guidance: Connect with a California Tech Equity CPA to calculate Form 540-ES estimated payments and protect against CA underpayment penalties.