Texas Supplemental Tax Regulations for Microsoft RSUs
Texas levies zero personal income tax on supplemental wages, RSU vests, or capital gains. Your statutory withholding is restricted exclusively to Federal supplemental (22%/37%) and FICA (Medicare/Social Security).
Texas Safe Harbor & Underpayment Penalties
No state safe-harbor required.
Employer Stock Plan Specifics: Fidelity Investments
Microsoft employees in Redmond, WA enjoy 0% state income tax on vesting wages, but face the full federal marginal spread. For senior SDEs and Partners whose base exceeds the $184,500 Social Security cap, every incremental vest dollar is taxed at 35% or 37% plus 2.35% Medicare.
When vesting at Microsoft, Fidelity Investments calculates automatic sell-to-cover withholding using Texas's statutory supplemental rate of 0.00% combined with the federal supplemental rate (22% on up to $1M). Because top earners in Texas reach marginal brackets exceeding these rates, you will face an incremental shortfall on April 15.
Localized CPA & Advisory Referral
Advisor Guidance: Pair with an Austin tech CPA to model federal safe-harbor withholding and optimize post-vest equity liquidation.