"We agreed she'd be a 1099" is not a classification. Neither is a signed contractor agreement, part-time hours, or the fact that everyone in your industry does it this way. Classification is determined by the working relationship itself, and the IRS test looks at three things.
The three-factor common law test
Behavioral control: do you direct how the work is done — set hours, require your tools and processes, provide training? Contractors deliver a result; you don't manage their method. Financial control: does the worker have their own business economics — invoices you from their own entity, carries their own tools and expenses, can profit or lose money, serves other clients? A worker whose entire income is you, paid a steady weekly amount, looks like an employee. Relationship of the parties: is there an open-ended arrangement, benefits, work that's core to what your business sells? A permanent, integral role points to employment regardless of what the contract says.
No single factor decides it. But the pattern we see fail most often: a full-time-hours worker, on your schedule, using your systems, with no other clients, doing the exact service your company sells. That person is an employee under any honest reading, and "1099 by agreement" won't survive an audit.
What misclassification actually costs
If the IRS reclassifies a worker, you owe the employment taxes you should have withheld and paid. Under the reduced rates of IRC Section 3509, that typically runs about 10–11% of the wages paid — per worker, per year, up to three years back — plus failure-to-file penalties and interest. One contractor paid $60,000 a year for three years is roughly a $20,000 federal problem before the state shows up. And the state usually does: unemployment insurance audits often trigger the federal exam (or vice versa), and states like California apply the even stricter ABC test, which presumes employment unless you prove otherwise.
Your two escape hatches
- Section 530 relief — if you had a reasonable basis for the classification (industry practice, prior audit, professional advice), filed 1099s consistently, and never treated similar workers as employees, you may keep the classification even if it's technically wrong. Filing the 1099s every year is the part businesses blow — miss that and Section 530 is gone.
- The Voluntary Classification Settlement Program (VCSP) — reclassify workers prospectively and pay just over 1% of the past year's compensation to those workers, with no interest, no penalties, and no audit of prior years. For a business sitting on years of exposure, it's remarkably cheap insurance.
A quick self-audit
- List everyone you paid on 1099 last year.
- Flag anyone working 30+ hours a week for you, on your schedule, with no other clients.
- Flag anyone doing the core service your business sells.
- Confirm every contractor has a W-9 on file and received a 1099-NEC for payments over $600.
- For flagged workers: fix it going forward via payroll or VCSP — prospective corrections are cheap; audits are not.
Reclassifying a worker onto payroll costs you roughly 8–10% more in employer taxes and admin. An audit costs multiples of that, plus back years. This is one of the few tax problems where the conservative choice is also clearly the cheaper one over any horizon longer than a year.