Outsourced HR and Payroll for SaaS

The moment you hire your first employee. State payroll tax accounts need correct registration from the first run, new-hire reporting has legal deadlines, and a single misclassified contractor creates retroactive liability. Most founders wait until they have 10 or 15 employees and discover months of accumulated compliance gaps. Outsourcing from day one costs far less than cleaning up mistakes made while a founder was running payroll between product meetings.

Every remote hire in a new state requires a separate payroll tax account, correct state income tax withholding, state unemployment insurance filings, and sometimes local jurisdiction compliance on top. The challenge isn’t the ongoing math. It’s the initial registration and the quarterly filing calendar across multiple states simultaneously. Milestone handles every registration, manages the filing calendar, and processes payroll across all active states so your team’s paychecks are always compliant.

Misclassification exposes SaaS companies to back payroll taxes on both the employee and employer side, unpaid federal and state income tax withholding, interest, and civil penalties. The IRS applies a 20-factor test that most founders haven’t read. California adds its own ABC test, which is stricter. A proactive classification review with documented rationale for each worker is the only reliable defense before an audit forces the question.

Equity compensation payroll requires supplemental withholding at each taxable event, coordinated with your cap table manager to catch vesting dates. RSU settlements trigger ordinary income and payroll taxes. ISO exercises create AMT preference items, not ordinary income, which changes withholding treatment. ESPP dispositions carry separate reporting rules. Milestone coordinates directly with your cap table platform so withholding is correct and employees receive accurate W-2s without IRS follow-up.

At 50 full-time equivalents, three things happen at once: ACA Applicable Large Employer status triggers mandatory coverage and 1094-C/1095-C reporting, federal FMLA obligations require a formal leave policy and tracking system, and many state-level leave requirements activate on their own thresholds. Companies that cross 50 FTEs without a compliance framework in place often face multiple simultaneous obligations they weren’t tracking. Milestone monitors your FTE count and builds the framework before you cross each line.

A PEO co-employs your workforce, pooling risk across its client base to lower benefits costs at smaller headcounts. Outsourced HR manages your functions without co-employment. Your employees stay yours, your carrier relationships are yours, and you keep full control over compensation and culture. For SaaS companies above 30 to 40 employees, outsourced HR typically offers more flexibility than a PEO, especially when equity compensation and investor reporting add complexity the PEO model wasn’t designed to handle.

Cost depends on headcount, active states, equity complexity, and scope of services. Most full-service providers price per employee per month. The relevant comparison is against in-house alternatives: a dedicated HR manager in a major tech market runs $90,000 to $130,000 per year in base salary before benefits, software, and the compliance liability that comes with one person managing a function they weren’t trained to scale. Milestone pricing is scoped to your stage. Contact our team for a custom proposal.

Yes. Milestone integrates directly with QuickBooks Online, Xero, and NetSuite. Every payroll run posts to your general ledger with correct cost center coding, department allocations, and accrual entries, without manual journal entries from your finance team. For companies running payroll and accounting through separate vendors, the integration typically cuts month-end close time by two to four days. Because Milestone manages both sides for most SaaS clients, it’s the same team running both the payroll and the close.