GC 1099-NEC Workpaper for Construction Subcontractors

The One Big Beautiful Bill Act (OBBBA) raised the 1099-NEC reporting threshold from $600 to $2,000 per payee per calendar year, effective for calendar-2026 payments filed in January 2027. The $600 threshold still governs calendar-2025 payments filed in January 2026, so the GC 1099-NEC workpaper for construction subcontractors looks different in two consecutive cycles: the early-2026 close runs on the old floor, and the early-2027 close is the first under the new one. The threshold is statutory and indexed for inflation, so the floor will keep moving rather than snapping back. Subcontractors paid between $600 and $1,999 in 2025 land on the 1099 file; the same payments in 2026 do not. Subs hovering near $2,000 need monitoring through December because a single late retainage release can push them over.

Nothing else about the cycle changes. The GC still issues 1099-NEC to non-corporate subcontractors paid $2,000 or more for nonemployee compensation, still files with the IRS by January 31, and still owes recipients a copy by the same date. The corporate exemption still applies, the materials-vs-labor split still applies, backup withholding still runs at 24% when a W-9 is missing, and the IRS B-Notice cycle still arrives every spring. The rest of this article is sized to a general contractor's reality: a vendor master that runs 30 to 200 subcontractors deep, a December payment register that mixes ACH, check, wire, and a handful of card-paid amounts, an LLC-heavy vendor mix that defies a blanket corporate-exemption flag, and a year-end close that runs in parallel with retainage release and final-lien-waiver reconciliation. Single-property landlords cutting checks to two contractors should read the small-scale rental-landlord 1099-NEC workflow instead — different scope, different risk pattern.

W-9 Box 3 and the single-member LLC reporting trap

Reportability turns on a single field. On Form W-9, Box 3 (Federal tax classification) tells the GC how the IRS treats the subcontractor for federal tax purposes, and that classification — not the legal name, not the d/b/a, not the AP clerk's intuition about the entity — decides whether each vendor lands on the 1099-NEC list.

Box 3 has the following federal-tax-classification options (Individual / sole proprietor / single-member LLC are grouped on a single line of the form, which is why the bullets below total six). For 1099-NEC purposes at this stage, here is what each means; the corporate-exemption carve-outs are walked in detail in the next section.

• Individual / sole proprietor / single-member LLC. Reportable. The W-9 may list a TIN that is either the owner's SSN or the LLC's EIN, but the federal classification governs.
• C corporation. Generally exempt under the corporate exemption.
• S corporation. Generally exempt under the corporate exemption.
• Partnership. Reportable. Partnerships are not corporations and the corporate exemption does not reach them.
• Trust/estate. Reportable. Trusts and estates are not corporations either.
• Limited liability company. This is the field that requires the closest read. An LLC checking this box must enter C, S, or P in the adjacent field to indicate how the LLC has elected to be taxed. C and S route to the corporate exemption; P (partnership) is reportable. If the field is blank, the W-9 is not complete — the GC should request resubmission rather than guess.
• Other. Read the explanation field. The vendor is reportable unless the entity it describes is a true corporation.

The trap that catches GCs at scale is the single-member LLC. An LLC with one owner that has not affirmatively elected to be taxed as a corporation defaults to disregarded-entity status under federal tax rules, which means the IRS treats the LLC as a sole proprietorship for federal tax purposes. A subcontractor invoicing as "Smith Mechanical LLC" with one owner and no S-corp election is, for 1099-NEC purposes, a sole proprietor — and therefore reportable. The "LLC" suffix on the legal name reads as corporate to anyone who has not internalized the matrix, and the workpaper bug shows up as missing 1099s for entities the GC assumed were exempt. At a vendor count of 30 to 200 subcontractors, where LLCs dominate the mix, this is the single most common error.

The correct read for the SMLLC W-9 is mechanical: confirm that Box 3 is filled in as Individual / sole proprietor / single-member LLC (not the LLC line with C, S, or P), and treat the vendor as reportable regardless of what the legal name implies. If a single-member LLC has actually elected S-corp taxation, the W-9 will show the LLC line with "S" entered alongside it; that vendor moves to the corporate-exemption side of the workpaper. The election state lives on the W-9, not in the GC's head.

Foreign-vendor classification runs on a different track entirely. Subcontractors that are foreign persons or foreign entities provide the W-8 series rather than W-9 and route to Form 1042-S rather than 1099-NEC; the rate, the withholding mechanics, and the filing path are all separate. If your subcontractor list includes any cross-border vendors, the cross-border counterpart for foreign vendors using Form W-8 and Form 1042-S covers that workflow. The rest of this article assumes US-person subcontractors with W-9s on file.

The corporate exemption and where the construction-relevant carve-outs land

Once Box 3 confirms a subcontractor is a C corporation or an S corporation, payments to that vendor for ordinary trade work are generally exempt from 1099-NEC reporting, regardless of amount. This is the corporate exemption. A C-corp masonry sub paid $400,000 across the year still gets no 1099-NEC; the corporate-exemption flag on the vendor record removes them from the workpaper for routine payments.

Four exceptions override the exemption, and three of them rarely surface for a GC. The fourth does.

Attorney fees are reportable on 1099-NEC for nonemployee compensation (or on 1099-MISC Box 10 for gross proceeds tied to a settlement) even when the recipient is a corporate law firm. The corporate exemption does not reach legal fees. Medical and health-care payments are reportable on 1099-MISC even when paid to a corporation; this is the same override pattern but a different form, and it almost never surfaces in construction AP. Cash purchases of fish for resale override the corporate exemption on 1099-NEC; not relevant to general contracting. Federal executive agency payments carry their own reporting regime that overrides the corporate exemption; also not relevant to a private GC's vendor mix.

The construction-specific application of the attorney-fees exception is worth carving out. If the GC pays a subcontractor's attorney directly under a settlement — for example, in a mechanics-lien dispute or a contract-claim resolution where the GC funds a settlement payment to the sub's law firm rather than to the sub — that attorney's fee is reportable on 1099-NEC even when the law firm is a corporation. Uncommon at most GCs, but documented when it does happen. Either an internal AP review or the outside CPA should flag any direct payment to a law firm during the year and confirm the correct form (1099-NEC for fees for services, 1099-MISC Box 10 for gross-proceeds settlement amounts) before the workpaper closes.

Corporate-exemption status is verified one way: against a current W-9 in the file. Oral assurance does not meet the standard, and "they were a C-corp three years ago" does not survive an entity change the GC never noticed. If the W-9 in the vendor file is more than three or four years old, predates a known restructure, or was furnished under a prior legal name, request a refreshed W-9 before applying the exemption flag for the current year — the alternative is a missing 1099 and the accuracy-penalty exposure attached to it.

A reminder on form choice: the corporate-exemption carve-outs above route to whichever form matches the payment type — fees-for-services to 1099-NEC, gross-proceeds settlements to 1099-MISC Box 10, medical and health-care payments to 1099-MISC. The two forms share the January 31 deadline and the same e-file path, but the boxes are distinct.

Splitting materials and labor on subcontractor invoices

The IRS rule for the materials-vs-labor split is short: when a subcontractor's invoice combines labor and materials and the two amounts are not separately stated, the full combined amount is reported as nonemployee compensation on 1099-NEC. When the invoice cleanly separates labor and materials with dollar amounts attached to each, only the labor portion is reportable; the materials portion is excluded.

That rule sounds simple in the abstract and gets murky in practice because subcontractor invoicing patterns vary by trade. Applying the rule incorrectly cuts both ways. Over-reporting bundles materials into the 1099-NEC aggregate, which inflates the sub's reported nonemployee compensation and creates reconciliation work on the sub's own return. Under-reporting strips out amounts that should have been included and exposes the GC to accuracy penalties on the form. Neither error is catastrophic on a single invoice; across a 30-to-200-vendor file with thousands of line items, the pattern compounds.

The trade-by-trade picture is where the rule earns its operational weight.

Mechanical. A mechanical sub installing a rooftop unit invoices for the unit, the ductwork, the sheet metal, and labor as one combined amount, often presented as "RTU-3 install per change order — $48,200." The ductwork and the unit are materials; the install is labor; nothing is separately stated. Combined, so the full $48,200 lands in the 1099-NEC aggregate.

Electrical. An electrical sub furnishes labor for a panel upgrade and the materials — the panel, breakers, conduit, wire — come on a separate invoice from a supply house, billed to the GC directly. The electrician's labor invoice is reportable in full as nonemployee compensation. The supply house's invoice is a vendor payment to a separate entity altogether, and whether the supply house earns a 1099-NEC depends on its own W-9. The supply house is typically a C-corp distributor and therefore exempt under the corporate exemption — so in practice the materials drop out of the 1099 picture entirely on this trade pattern.

Plumbing. A plumbing sub invoices labor and fixtures together but lists fixtures as separate line items below the labor line, with quantities, unit prices, and line totals. If the line items separate cleanly with dollar amounts attached, only the labor lines are reportable. If "materials" appears as a single lump-sum line below labor with one dollar amount, that still counts as separately stated; the labor amount and the materials amount are each identified. The judgment call comes when an invoice writes "labor and materials per scope — $22,500" with no breakdown at all; that is not separately stated, and the full amount is reportable.

Drywall. A drywall sub invoices labor only and the GC has a separate supply order for drywall sheets and joint compound through a building-products distributor. The drywall sub's invoice is reportable in full as labor; the distributor follows its own W-9 status and almost always lands as a corporate exemption. This is the cleanest trade pattern from a 1099 perspective because the work and the materials never share an invoice.

Concrete. A concrete sub delivers ready-mix and places it on the same line — "350 yards delivered and placed — $58,000." Combined unless the invoice splits delivery (materials) from placement (labor) with dollar amounts on each. Many concrete subs do split because mix tickets carry the truck-by-truck cost, but the invoice has to actually reflect the split for the rule to apply.

The operational implication is the same across trades. If a subcontractor consistently invoices in a combined pattern and the GC wants to track labor separately for cost-coding, certified payroll, or 1099 purposes, the cleanest fix is to require separate-line invoicing in the subcontract terms going forward. Back-allocating amounts on the workpaper after the fact, using a percentage estimate or a labor-rate assumption, does not meet the separately-stated standard and will not hold up if questioned.

Filtering the December payment register: method, retainage, and lien waivers

The payment-aggregate column on the workpaper is the year-to-date sum of payments to each subcontractor for the calendar year, filtered to include only the payments that count toward 1099-NEC. Pulled straight from the GL payment register without filtering, those totals double-count card-paid amounts and miscount any retainage release that landed across the calendar-year line. Two filters and one reconciliation get the totals right.

The first filter is payment method. ACH, check, and wire payments count toward the 1099-NEC aggregate. Credit-card payments and amounts settled through third-party payment networks (PayPal, Stripe-routed payments, marketplace payouts) are excluded because the processor reports those amounts to the IRS on Form 1099-K instead. The practical impact is small for most GCs since subcontractors are rarely paid by card, but the filter still has to run — an unfiltered register lumps card-paid amounts into the 1099-NEC aggregate and duplicates them against the processor's 1099-K.

The second filter is the calendar-year cutoff, which becomes operationally interesting at year-end because of retainage. Retainage is held back across the life of the contract and released either at substantial completion or at final acceptance. A retainage release wired or cut on December 30 lands in the calendar year just ending and adds to that subcontractor's payment aggregate; the same release dated January 2 lands in the next year. Controllers releasing retainage in late December should be aware that those late-year releases sometimes push subs over the $2,000 threshold who would otherwise have been below it, especially in the early-2027 cycle when the threshold is new and several mid-tier subs are running close to it. The reverse is also legitimate: holding a retainage release across the calendar-year line for cash-flow or scheduling reasons is a real timing decision, but it has 1099 consequences for the sub on both sides of the cut, and the workpaper has to reflect the actual payment date, not the contract event the release relates to.

The third piece is the final-lien-waiver reconciliation, which the same controller is usually running in the same January window. A final unconditional lien waiver from a sub identifies the total contract amount paid to date — a number the sub stands behind in writing in exchange for the final release. That figure should reconcile against the workpaper's payment-aggregate column for that vendor. Gaps in either direction (lien waiver higher than workpaper, or vice versa) usually trace to a missed retainage release, a payment posted to the wrong vendor in the GL, or a payment recorded under a parent company name when the sub bills under an affiliate. Some discrepancies trace further upstream to a schedule-of-values line misallocated when processing G702 and G703 pay applications from subcontractors earlier in the year, in which case the resolution is to walk the affected pay applications back to the schedule of values.

One last exclusion: reimbursements separately stated on the invoice and supported by receipts (per-diems, travel, materials passed through with documentation) are excluded from the 1099-NEC aggregate; reimbursements bundled into a labor invoice without separate identification are not.

Backup withholding, Form 945, and configuring AP for missing W-9s

When a subcontractor has not furnished a valid W-9, or when the IRS has notified the GC that the TIN on file is incorrect, the GC has to withhold from each reportable payment and remit the withheld amount to the IRS. According to the IRS's 24% backup withholding rule, when a payee fails to furnish a correct taxpayer identification number to the payer, the payer is required to withhold backup withholding at the current rate of 24 percent on reportable payments. That is the operative number every AP supervisor needs to know going into a new vendor relationship: no W-9, withhold 24%.

The mechanic that determines whether the GC actually does this is a configuration setting on the vendor record. In most accounting platforms used by mid-market GCs — QuickBooks Enterprise, Sage 100 Contractor / Sage 300 CRE / Sage Intacct, Acumatica, CMiC, Procore-integrated AP modules, Foundation, Viewpoint Spectrum, Viewpoint Vista — each vendor carries a 1099-eligibility flag and a backup-withholding flag. When a vendor's W-9 is missing or invalid, the backup-withholding flag should be set on the vendor record so that every payment run automatically withholds 24% from gross before issuing the net check or ACH. The vendor receives 76% of the invoice; the IRS receives the rest.

Where this breaks down is when the configuration is not maintained. A new sub onboarded mid-year without a W-9, with the backup-withholding flag left off and the 1099-eligibility flag left at default, has been paid gross all year. The GC carries the liability for the unwithheld amount, and the discovery usually happens in January when the controller is building the workpaper and notices that several vendor records have neither a W-9 in the file nor a withholding history. At that point the underwithheld amount is the GC's, not the sub's.

Backup-withheld amounts are remitted to the IRS using Form 945 (Annual Return of Withheld Federal Income Tax). Form 945 is filed annually by January 31 of the following year, and the same withheld amounts are also reported in Box 4 of the recipient's 1099-NEC so the sub can claim credit for them on their own return. Deposit timing during the year depends on the GC's deposit schedule (monthly or semi-weekly under the same rules that govern other federal-tax deposits); a GC with substantial backup-withholding volume usually lands on a semi-weekly schedule. The deposits are made through EFTPS, not with the Form 945 itself.

The prior-period correction path depends on timing. If the missed withholding is discovered before the next payment to the same vendor and within the same calendar year, the GC catches up by withholding the underwithheld amount from subsequent payments, up to the IRS-permitted catch-up limit. If discovery happens after the year-end close, the GC owes the underwithheld amount as a payor liability and faces failure-to-deposit and failure-to-file penalties on top. Box 4 of the 1099-NEC reports only what was actually withheld and remitted, not what should have been, so the corrective filings have to be sequenced before the 1099-NECs transmit.

The mid-year W-9 correction is the cleanest case. When a vendor furnishes a corrected W-9 mid-year that resolves the missing-data condition, backup withholding stops on the next payment going forward. Amounts already withheld in the same calendar year stay withheld, stay reported in Box 4, and stay remitted on Form 945; the sub reconciles them as a credit on their own return. The GC does not refund the withheld amounts. The sub files for them through the IRS via their own tax return.

Any of the major construction-AP platforms supports the backup-withholding workflow; how cleanly each handles the flag, the W-9 attachment per vendor, and the year-end 1099 export is a separate question covered in the broader construction AP automation software comparison.

IRS TIN-Match and the CP2100 B-Notice cycle

Every TIN/name pair on the workpaper has to match the IRS's records when the 1099-NEC file goes in. Mismatches don't bounce the filing — the form transmits and the IRS accepts it — but they generate notices the following spring that the GC then has to work through, vendor by vendor, on a 15-business-day clock. The cheaper move is to validate before transmitting.

The IRS TIN-Match service, accessed through IRS e-Services, is the bulk pre-filing validation tool. The GC submits each payee's TIN and legal name as the sub furnished them on the W-9; the service returns a match or no-match response. Running TIN-Match against the entire 1099-NEC payee list before transmitting is the standard pre-filing checkpoint at GC scale. It catches typos in the TIN (a transposed digit, an SSN entered as an EIN), name-change mismatches (the sub married, divorced, or restructured and the W-9 in the file no longer matches the IRS record), and EIN/SSN swaps (a single-member LLC submitted under the LLC's EIN when the IRS still keys on the owner's SSN, or vice versa).

The cost of skipping the validation is operational rather than financial. Every TIN mismatch the IRS catches turns into a CP2100 or CP2100A notice the following year, and the GC then has to run the B-Notice workflow described next. At a vendor count above a few dozen, pre-filing validation moves the work from after-the-fact remediation across many separate vendors to a one-time correction batch handled before the file goes in.

The B-Notice cycle runs in concrete steps that bear walking through, because most generic content treats it as a one-line aside.

The IRS sends Notice CP2100 (paper-based, larger filers — typically GCs at any meaningful scale) or CP2100A (smaller filers) each year, listing every TIN/name mismatch from the prior filing season. The notice arrives in the spring or early summer following the January filing.

Within 15 business days of receiving the notice, the GC must send a "First B-Notice" to each affected payee, requesting a corrected W-9 and explaining that backup withholding will start if no response is received. The First B-Notice has specific content requirements (the IRS publishes a template); a generic "please send a new W-9" email does not satisfy the rule.

If the payee responds with a valid W-9 within 30 days of the First B-Notice, the GC updates the vendor record, swaps the corrected TIN into the AP system, and no withholding starts. If the payee does not respond within 30 days, the GC must begin backup withholding 24% on all subsequent payments to that vendor — and the backup-withholding flag on the vendor record (covered in the previous section) is the operational lever that makes that happen.

In subsequent years, if the same TIN appears on a CP2100 again, the GC sends a "Second B-Notice" instead of a First. The Second B-Notice has a stricter cure path: the payee must provide either a copy of their Social Security card (for individuals and SMLLC owners reporting on SSN) or an IRS Letter 147C verifying the correct EIN (for entities). A refreshed W-9 alone does not satisfy a Second B-Notice. This is where the cycle gets administratively heavier, because some subs simply do not respond, and the GC ends up running backup withholding indefinitely on those vendor records.

For a GC with 100 to 200 vendors on the 1099-NEC file, B-Notices arrive every year. They are not an edge case; they are an annual workload. Building the response into the AP coordinator's calendar with a tracking log of First-vs-Second B-Notice status per vendor (notice received date, B-Notice sent date, payee response date, withholding-start date) keeps the cycle from becoming a fire drill in the spring. The IRS publishes detailed B-Notice procedures in Publication 1281; the controller or outside CPA should keep that reference at hand the first time the cycle runs in-house, because the form requirements and the timing rules are mechanical and unforgiving.

Filing: e-file thresholds, January 31, and state requirements

Form 1099-NEC must be filed with the IRS and furnished to the recipient by January 31 of the year following the calendar year of payment. The two pieces — IRS filing and recipient copy — share the same deadline. Unlike some other forms in the 1099 series, 1099-NEC does not have an automatic 30-day filing extension; missing the deadline triggers per-form penalties that scale with how late the filing lands.

E-filing is mandatory for any GC reading this article. Under current rules, any filer required to file 10 or more information returns in aggregate (across all return types in a calendar year, not just 1099-NEC) must e-file. A GC issuing 30 to 200 1099-NECs is well above the threshold; the question is which path, not whether. The IRS's IRIS portal (Information Returns Intake System) is the no-cost federal e-file route and accepts CSV uploads or direct entry. Most 1099 software platforms — Tax1099, Track1099, Yearli, Sovos — also file directly to the IRS, as do the 1099 modules built into the major construction-AP systems. The pricing per form is modest at GC volume; the operational benefit is recipient-copy delivery (electronic or printed-and-mailed) bundled into the same workflow.

Penalty tiers scale by how late the filing is. Filing within 30 days of the deadline carries a smaller per-form penalty; by August 1, larger; after August 1, larger still; intentional disregard, larger again with no annual cap. Each tier is capped annually with separate caps for small versus large filers. The point is operational rather than budgetary: file on time and accurate. Penalty calculation is not a planning input.

State filing is the part of the cycle that gets either over-explained or skipped entirely in most published guides. Most states accept federal filings through the IRS Combined Federal/State Filing (CFSF) program, which forwards 1099 data to participating state revenue departments automatically when the GC indicates participation in the federal transmission. CFSF removes the need for a separate state filing in those states.

A meaningful minority of states do not participate in CFSF, or participate but require additional state-level filing on top of the federal/CFSF route. Several northeastern and Pacific states fall into this group, with their own portals, their own deadlines, and in some cases their own forms. State-specific rules also sometimes diverge on the threshold itself (a state may keep a $600 reporting threshold even where the federal threshold is $2,000), on the form (some states aggregate on a state-equivalent return rather than the federal 1099-NEC), and on the deadline (a state deadline may sit ahead of January 31). The CFSF route does not relieve the filer of these state-specific deviations; it relieves only the duplicate filing where the state accepts the federal data as filed.

The practical guidance is narrow rather than encyclopedic: check the state revenue department's 1099 filing page for every state where the GC is doing business with subcontractors, in the December planning window. Once the matrix is documented for a given GC, it doesn't change unless the business expands into a new state. Regional GCs filing in three or four states can handle the manual portion in a half-day on top of CFSF; nationals filing in many more usually find a multi-state-capable 1099 platform pays for itself in AP coordinator time during the same week the workpaper is being finalized.

Building the workpaper from W-9 PDFs, invoices, and the GL

The workpaper itself is straightforward at the structural level: a single-tab Excel workbook (or its equivalent inside the GC's accounting system) with one row per active subcontractor and columns for legal name, TIN, W-9 Box 3 classification, corporate-exemption flag, address, year-to-date payment aggregate (method-filtered), labor portion, reportability flag, backup-withholding flag, and Box 4 backup-withheld amount. Anything else — project codes, retainage status, B-Notice history — is nice to have, not required.

Three data sources feed those columns. The W-9 PDF set sits in the AP shared drive, typically as an unstructured folder of scans and emailed forms with multiple versions per vendor across years; the workpaper needs the legal name, business name where different, Box 3 classification (with LLC sub-classification where applicable), TIN, address, and signature date out of each one. The subcontractor invoice corpus holds the materials-vs-labor splits the labor-only column reads from, when the invoices separate the two. The GL payment register is already structured — vendor, date, amount, method, reference — and just needs filtering and aggregation.

The math is not the bottleneck. The bottleneck is getting the W-9 data points and the materials-vs-labor splits out of the PDF set into rows the workpaper can join against. If those two surfaces become structured tables, the rest is mechanical.

That is the surface where extraction tooling earns its keep — turning a folder of W-9 PDFs into a vendor-master table with TIN, Box 3 classification, address, and signature date as columns, and parsing materials-vs-labor splits out of subcontractor invoice line items so the labor-only column populates without manual line-by-line review. Our own product handles exactly this work: the user uploads the PDFs, describes what to pull out in a natural-language prompt ("extract the legal name, TIN, Box 3 classification, address, and signature date from each W-9"), and downloads structured Excel, CSV, or JSON ready to drop into the workpaper. The same approach handles the invoice corpus — a prompt asking for invoice number, vendor, date, line-item description, labor amount, and materials amount produces the line-level table the labor-only column reads from. You can extract W-9 PDFs and subcontractor invoice line items into the 1099 workpaper with the same workflow across both document sets, which collapses the two largest manual surfaces of the January cycle.

The 1099-NEC workpaper does not run alone — retainage-release reconciliation and final-lien-waiver review compete for the same controller's attention in the same window, and the three workflows share the vendor file. Clean data sources at the start of January are what keep the 1099 close ahead of the deadline rather than chasing it.