The rules are federal and the same for everyone. What differs by sector is which payees you have, which extra databases you must check, and where the process breaks. One page per sector, mapped back to the general guides.
Provider and vendor TINs, NPI and Medicare enrollment checks, OIG and state Medicaid exclusions, and medical-payment reporting on 1099-MISC.
Rent to individual owners, 1099-MISC box 1, owners who won't give an SSN, and the single-member LLC problem at scale.
Tens of thousands of payees onboarded online, 1099-K vs 1099-NEC, real-time TIN matching at signup, and backup withholding at volume.
Grants and vendor payments, SAM.gov exclusions, foreign visitors and students on W-8, and public-entity procurement rules.
1099-INT and 1099-DIV at account-opening scale, C-Notices, CIP overlap, and why the bank's own W-9 process is the compliance control.
The attorney exception to the corporate rule, settlement gross proceeds on box 10, who gets the 1099 on each side of a case, and trust-account payees.
W-2G instead of 1099, the 2026 $2,000 slot and bingo threshold, regular vs backup withholding, and TIN capture at the cage.
Owner-operators, FMCSA authority and insurance checks alongside the TIN match, double-brokering fraud and factoring companies.
Form 1099-DA from 2025, withholding relief that depends on IRS-matched TINs, and which 1099 regime applies to which payment flow.
Exempt payee, not exempt payer: grants to individuals, honoraria, prizes, research subjects, and a W-9 process for a small finance team.
Claim payments, attorney gross proceeds, medical providers, agents and adjusters, and TIN verification inside the claims workflow.