Merging Vendor Records After a Portfolio Add-On Closes

Before touching vendor data, confirm with your deal counsel and accountant whether the add-on remains a separate legal filing entity after close or gets folded into the platform company's EIN. This single fact determines everything downstream: separate entities file separate 1099s even for a vendor common to both, while a folded-in entity means that vendor's combined total, across the stub period before close and the months after, needs consolidating onto one form. This is a legal and tax question first, not an accounting-software question, so get it in writing from your deal team before any vendor data gets touched, rather than assuming the accounting system's default entity structure reflects the actual post-close legal reality.

Even when the legal answer is that each entity files separately, build one combined list of every vendor who worked with either company this year, flagging which ones appear in both. This isn't for the filing itself, it's for review: say a consultant crossed $600 at each entity separately, that's easy to file correctly twice, but a consultant who was under $600 at each one individually while over it combined is the case most likely to get missed without this combined view. Keep this combined list as a standing artifact through the integration period, not a one-time export, since new vendor overlaps can surface for months after close as the two organizations' operations continue merging.

A consultant paid by the target company in the months before close, then paid by the surviving entity after close, may need careful handling depending on whether the entities remain separate filers. Get clarity from your deal team on exactly which entity's books the stub-period payments live in, and confirm that number doesn't get silently dropped during the integration of accounting systems, which is a common way pre-close payments go missing from any year-end total. If the target used a different accounting platform before the deal, export its full vendor payment history before that system gets decommissioned, since a vendor list that only exists in a system nobody logs into anymore is effectively lost the moment access is cut off.

If both entities remain separate filers, you can still manage both from a single Tax1099 or Track1099 account, filing under each entity's own EIN, which centralizes the operational work without changing the legal filing structure. Confirm your chosen platform actually supports managing multiple distinct filer identities from one login, since that's the feature that matters most for a portfolio company integrating an add-on, not any difference in the core filing mechanics. Getting this consolidation right in the first post-close filing season also sets the pattern for every future add-on, so it's worth documenting even if this deal feels like a one-off right now.

National wage data puts the median pay for the accountants and auditors who typically handle this kind of post-close reconciliation at $83,680 a year¹. Treat this work as part of your integration budget from the start, not as an unplanned addition discovered when the first post-close filing season arrives, since the vendor consolidation work is genuinely more involved than a normal year's filing.

If your portfolio company's add-on is one of several this year, or if the platform company plans further add-ons, raise the vendor consolidation process as a repeatable step in your integration playbook rather than solving it fresh each time. A documented process, including which platform handles multi-entity filing and how the combined vendor review gets built, saves real time on the next deal. A fund running several portfolio companies through similar add-on activity benefits from standardizing on one filing platform across the portfolio, so the finance team isn't relearning a different tool's workflow at every new deal.

Use this repeatable checklist for every add-on:

1. Confirm with deal counsel and your accountant whether the add-on stays a separate filer or folds into the platform company's EIN.
2. Build one combined vendor list covering both companies, flagging every vendor who appears in both.
3. Reconcile payments around the close date, based on whether the two entities remain separate filers.
4. Decide whether to file from one platform account or two, keeping each entity's own EIN wherever it still applies.
5. Budget the integration reconciliation as its own line item, and record the process in your integration playbook for future add-ons.