Massachusetts Supplemental Tax Regulations for Google (Alphabet) RSUs
Massachusetts withholds at the standard 5.0% flat income tax rate. However, under the Massachusetts Fair Share Amendment, taxable income above $1,000,000 is subject to an additional 4% surtax (total 9.0%), creating a 4% withholding shortfall on multi-million dollar vests.
Massachusetts Safe Harbor & Underpayment Penalties
Submit Form 8488 or quarterly Massachusetts estimated tax payments.
Employer Stock Plan Specifics: Charles Schwab / Morgan Stanley
Google utilizes a frontloaded monthly vesting schedule (33% across years 1 and 2). Because monthly vests are treated as supplemental wage distributions, Schwab withholds federal tax at flat 22%. Googlers with total comp above $350k find that each monthly tranche underwithholds by 10% to 15%, compounding silently over 12 months.
When vesting at Google (Alphabet), Charles Schwab / Morgan Stanley calculates automatic sell-to-cover withholding using Massachusetts's statutory supplemental rate of 5.00% combined with the federal supplemental rate (22% on up to $1M). Because top earners in Massachusetts reach marginal brackets exceeding these rates, you will face an incremental shortfall on April 15.
Localized CPA & Advisory Referral
Advisor Guidance: Find a Boston tech CPA experienced with the Massachusetts 4% Fair Share Amendment ("Millionaire's Tax") on high equity vests.