Here's the direct answer: most high-income returns don't fail in an audit. They fail in a computer. The IRS matches every W-2, 1099, and K-1 it receives against what your return reports, and any mismatch generates an automated notice — no human required.
Once your income includes equity compensation, pass-through entities, rentals, or multiple states, the number of places a return can silently break multiplies. A generalist preparer working through a 400-return season doesn't have time to reconcile your brokerage basis or rebuild a missing K-1 basis schedule. So the error ships, and you find out eighteen months later.
| Income situation | Common filing error | What it costs you |
|---|---|---|
| Equity compensation (RSUs, ISOs, ESPP) | Broker-reported basis not adjusted for income already taxed at vesting | The same income gets taxed twice |
| Multiple K-1s | No basis or at-risk tracking from year to year | Losses disallowed, distributions taxed unexpectedly |
| Rental real estate | Depreciation errors and mistracked passive losses | Lost deductions now, painful recapture surprises later |
| Multi-state income | Wrong state sourcing, missed credits for taxes paid | Double taxation of the same dollars |
| S-Corp ownership | Books that do not tie to the return, undocumented reasonable comp | Notice exposure and a weak audit position |
Your tax return is a system of record, not a formality.
Every basis schedule, carryforward, and election on this year's return determines what's possible on the next five. Filing done sloppily doesn't just risk notices — it destroys the paper trail your future strategies depend on.
