Additional Medicare Tax
In accounting, additional Medicare Tax means a further 0.9% Medicare tax an employer must withhold on an employee's wages over $200,000 in a calendar year, from the pay period they pass it. Employee-only: there is no employer match.
Authority: IRS Pub. 15 (2026), §9 (opens in a new tab). Sources
The lesson that teaches this
From the free founder back-office course, taught on one company's books, with exercises to work it yourself.
For founders
The same idea written for a founder: what it costs a startup that ignores it, and what to do in a real month.
- Form 941 and payroll tax deposits for startupsWhat Form 941 reports, monthly vs semiweekly deposits, the $100,000 next-day rule, FUTA, the R&D payroll credit, and what your provider can’t do.
- Payroll journal entries, from gross to netGross wages, employer taxes, withholding and net pay as journal entries: what each payroll run books, how to accrue it at month end, and where benefits go.
What it is not called
Each of these means something else. Use one here and an accountant reading the product notices.
- Medicare match
- net investment income tax
Components that render the terms it depends on
No component names this concept outright, but it's built from terms that components do name. These render period.
4Swaps & FX
Family spec5Ledger & tables
Family spec- PeriodPickerFiscal-aware. Never assumes January.
- FluxAnalysisPeriod-over-period explanations.
- ProfitAndLossP&L with period comparison and variance.
- ReportHeaderEntity, statement, period, basis, currency, as-of. Every figure states its basis.
- StatementTableThe shared shell: hierarchy, periods, rules.
- StatementToolbarBasis, period, comparison, currency, consolidation.
9Accounting core (GL)
Family spec11Payables (AP)
Family spec12Close, controls & consolidation
Family specAlso in Payroll
Defined in Lexicon. This page is generated from that document, so the two can't disagree.