Somewhere around late January, forms start arriving from your clients, and which form shows up depends less on what work you did than on how the money moved. Here is the map for a consulting practice.
The 1099-NEC for direct client payments
The workhorse is Form 1099-NEC, Nonemployee Compensation. Any business that paid you $600 or more during the calendar year for consulting services, by check, ACH, or wire, must file one with the IRS and send you a copy by January 31. Each client files separately, so a consultant with five retainers can expect up to five forms, each showing that client's total for the year. Expect a Form W-9 request from every new client's bookkeeper; returning it promptly with your correct name and taxpayer identification number prevents backup withholding and prevents the January scramble. Two common gaps are worth knowing. Clients who paid you less than $600 send nothing, and individuals who hired you personally, rather than through a business, are generally not required to file. Neither gap changes your side: the income is taxable and belongs on your Schedule C regardless. Also, if you operate as an S corp, clients generally stop issuing you 1099-NECs at all, since payments to corporations are largely exempt from the requirement.
The 1099-K when payments run through processors
When clients pay through credit cards or third-party payment platforms, the reporting duty moves to the payment processor, which issues Form 1099-K summarizing the gross amount processed. Two cautions come with it. First, the federal 1099-K reporting threshold has changed in recent years and some states set their own lower thresholds, so check current IRS guidance rather than assuming last year's number. Second, the 1099-K reports gross processed volume, before the platform's fees came out, so the form can show more than you actually received; you report the gross and deduct the processing fees as a business expense. The overlap trap: a client should not issue a 1099-NEC for payments made by card, since the processor's 1099-K covers those, but some do anyway. Reconcile every form against your own deposit records so the same revenue is not counted twice on your return.
Income with no form at all still counts
A meaningful slice of consulting revenue arrives with no 1099 attached: the under-$600 client, the overseas client outside the US reporting system, the individual founder who paid you from a personal account. The IRS taxes income, not paperwork, and your Schedule C should be built from your invoices and bank deposits, with January's forms used purely as a cross-check. When a 1099-NEC arrives overstating what a client paid, ask the client for a corrected form before filing, because the IRS matches form totals against your return, and unexplained gaps generate notices. The consultants who sail through January are the ones whose books already knew the answer before the envelopes arrived.