A mid-market finance tech stack is the set of connected systems a finance team uses to record, approve, close, consolidate, plan and file. For a company operating in both the US and the UK, it has to do two jobs at once: run a clean monthly close and meet filing rules that now assume software, such as HMRC's Making Tax Digital for VAT and the IRS move to IRIS for Forms 1099.
This guide builds the mid-market finance tech stack one layer at a time, starting with the general ledger and ending with tax filing and e-invoicing readiness. It does not rank vendors. Each section explains what the layer must do, what to test before you buy, and which 2026 compliance rule touches it.
The stack should follow how the business runs. Before you compare any software, write down the answers to these questions and keep them with the project file:
A clean chart of accounts with dimensions for department, location and project should be agreed before any build starts. Every later layer posts into it, and fixing it after go-live means remapping every integration.
The table below is a planning map. Use it to check that each layer has an owner and a defined connection to the ledger.
| Layer | What it must do | US rule that touches it | UK rule that touches it |
|---|---|---|---|
| ERP / general ledger | Multi-entity books, dimensions, approvals, audit trail | Vendor TIN and payment data for Forms 1099 | MTD for VAT digital records |
| Accounts payable | Invoice capture, matching, approvals, payment release | 1099 flags on vendor master; $2,000 threshold for 2026 payments | VAT on purchase invoices; e-invoice receipt from 2029 |
| Close management | Task lists, reconciliations, sign-offs | Evidence for audit and internal controls | Evidence for audit and VAT review |
| Consolidation | Eliminations, currency translation, group reports | US GAAP group reporting | UK statutory group accounts |
| FP&A | Budgets, forecasts, scenarios on live actuals | None directly | None directly |
| Tax and filing | VAT return submission, information returns | IRIS for e-filing; 10-return threshold | MTD-compatible software for VAT returns |
The ledger is the system of record. At mid-market scale it needs native multi-entity and multi-currency support, so that intercompany balances and revaluation run inside the system instead of in a spreadsheet. Test three things in a demo using your own data: posting a journal with full dimensions, running an entity-level trial balance, and producing a consolidated view without exporting to Excel.
Access control belongs in this layer too. Role-based permissions, single sign-on and multi-factor authentication matter more when part of the team works remotely or offshore. If the ledger cannot show who created and who approved each entry, the audit trail will have to be rebuilt elsewhere.
AP is where most transaction volume enters the stack. The layer should capture invoices, match them to purchase orders and receipts where that applies, route approvals and release payments with the creator, approver and payer kept separate. Our guide to automated accounts payable solutions covers the business case and rollout in detail.
For US filers, the vendor master is also where Form 1099 reporting starts. Each reportable vendor needs a valid TIN, a 1099 flag and the correct box mapping. For tax years beginning after 2025, the IRS instructions say the reporting threshold for certain payments "increased to $2,000 and may be adjusted for inflation beginning in calendar year 2027" (IRS Instructions for Forms 1099-MISC and 1099-NEC). The full set of changes is covered in our explainer on the 2026 1099 reporting threshold. Check that your AP tool can apply the new amount to 2026 payments while keeping the old rules for earlier years.
A close tool, or the close module inside the ERP, holds the task calendar, reconciliation templates and reviewer sign-offs. The test is simple: at the end of any close, can a reviewer open one place and see every balance sheet reconciliation, who prepared it, who approved it and what evidence is attached. A 5-day monthly close checklist is a practical starting template for the task list.
This layer also carries most of the control evidence your auditors will ask for. Companies preparing for a first audit can map close tasks to the controls described in our SOX-lite internal controls guide, so that each control has a recurring task and an owner.
Groups with a US parent and a UK subsidiary, or the reverse, need intercompany eliminations, currency translation and group reporting that tie back to entity ledgers. Some ERPs handle this natively for simple structures. Dedicated tools become worth evaluating when entity count, ownership percentages or reporting deadlines outgrow the ledger. Our article on financial consolidation software benefits explains what this layer automates under ASC 810.
Planning tools should read actuals from the ledger through a live connection, so that budget owners work from the same numbers the close produced. Look for driver-based models, version control for scenarios, and row-level security so department heads see only their own cost centres. A reporting warehouse is optional at this size; it becomes useful when data from billing, CRM and payroll has to be joined with ledger actuals.
In both countries, this layer is where filing rules require software.
HMRC's guidance is direct: "You must now use compatible software to keep your VAT records and file your VAT Returns" (GOV.UK, find software that's compatible with Making Tax Digital for VAT). The same page describes "bridging software to connect non-compatible software (like spreadsheets) to HMRC systems", which is the usual route when a UK entity keeps VAT workings outside its ledger.
The design question is the chain of data from source records to the VAT return. Every transfer between systems in that chain must be a digital link, and manual copy and paste breaks it. Our guide to MTD for VAT digital links walks through what HMRC accepts and how VAT penalty points work. When you map integrations, mark each step in the VAT chain and confirm it moves data without rekeying.
The IRS describes IRIS as a system with "two intake channels: IRIS Taxpayer Portal/UI and IRIS Application to Application (A2A)" (IRS, e-file information returns with IRIS). The portal is "free" and web-based, which suits a company filing its own returns. The A2A channel is for software that transmits returns directly; the IRS notes that A2A filers use it "to e-file thousands of returns."
The older FIRE system is closing. The IRS says the last day to file information returns through FIRE is November 19, 2026 (3 p.m. Eastern time), and that IRIS will be "the only information returns electronic filing system" after January 1, 2027 (IRS, FIRE system page). Tax year 2026 Forms 1099, filed in early 2027, therefore go through IRIS. If your AP tool or filing provider transmitted through FIRE, confirm in writing that it has an IRIS Transmitter Control Code before January.
The e-file threshold is low. The IRS General Instructions state: "If you are required to file 10 or more information returns during the year, you must e-file," and "The 10-or-more requirement does not apply separately to each type of form" (IRS General Instructions for Certain Information Returns).
A US company with a UK subsidiary reviews its 2026 vendor payments in December. All payees below are US persons with valid TINs. The higher threshold applies to rents as well: the 2026 Form 1099-MISC instructions say to "Enter amounts of $2,000 or more for all types of rents" in box 1.
| Payee group | Payees | 2026 payments per payee | Form for 2026 |
|---|---|---|---|
| Contractors paid above $2,000 | 7 | $2,500 to $40,000 | Form 1099-NEC |
| Contractors paid $600 to $1,999 | 5 | $600 to $1,999 | None (below $2,000) |
| Landlords paid rent of $2,000 or more | 4 | $24,000 each | Form 1099-MISC |
| Total returns | 11 |
The company files 7 Forms 1099-NEC and 4 Forms 1099-MISC, a total of 11 information returns. Because the 10-return count is aggregated across form types, 11 is above the threshold and the company must e-file, which for these returns means IRIS. Under the old $600 threshold the same vendor list would have produced 16 returns. The higher threshold reduces the count, and the company still has to e-file. Our 1099 outsourcing workflow and automation article covers how to run vendor TIN collection and review ahead of January.
As of October 2026, the UK has set a date. The government's consultation response states: "As announced at Budget 2025, the UK will introduce mandatory e-invoicing for all VAT invoices from 2029" (GOV.UK, promoting electronic invoicing consultation response). The response defines e-invoicing as "the digital exchange of invoice data directly between buyers' and suppliers' financial systems", so a PDF sent by email will not count. As of October 2026, the government is still reviewing whether to adopt an existing standard or design a UK-specific one, and the response says an implementation roadmap will be published at Budget 2026.
For stack planning, the practical steps do not depend on the final standard:
For US entities, the same master data clean-up improves invoice accuracy and makes any later move to structured invoicing easier.
Each layer should connect to the ledger through a native connector or a documented API. Our guide to API integration for accounting workflows explains how to judge connectors and rate limits. Document these flows end to end, with the owner of each hand-off:
The pitfalls that cause rework are consistent across US and UK teams. Vendors and customers get created in more than one system, so masters drift apart. Connectors sync invoice headers without line-level dimensions, so reports by department never tie out. Sales tax and VAT logic sits in spreadsheets outside the ledger. And close tasks live in email, so sign-offs arrive late with no evidence attached.
AI features now appear in most layers, from invoice capture in AP to variance commentary in FP&A. Treat them as features of a layer you already need, and test them against your own documents and controls before relying on them. Our guide to implementing AI in your accounting department sets out how to choose use cases, prepare data and run a controlled pilot.
A phased rollout keeps the close running while the stack changes:
Time the go-live for the tax and filing layer around deadlines. A change to the 1099 process is safest when it is tested with a trial IRIS submission well before January, and a UK VAT change is safest at the start of a VAT period.
What is a mid-market finance tech stack? It is the set of connected systems a mid-sized finance team uses for the ledger, payables, close, consolidation, planning and tax filing. The aim is one source of truth in the ledger, with every other layer posting into it through a documented connection.
Do UK businesses have to use MTD-compatible software for VAT? Yes. HMRC guidance says businesses must use compatible software to keep VAT records and file VAT returns. Bridging software can connect spreadsheets to HMRC systems if the data chain stays digitally linked.
Can we still file Forms 1099 through FIRE? The IRS says the last day to file through FIRE is November 19, 2026, and that IRIS will be the only electronic filing system for information returns after January 1, 2027. Tax year 2026 returns filed in early 2027 go through IRIS.
How many Forms 1099 trigger mandatory e-filing? Ten or more information returns in a year, counted across all form types combined. A company filing 6 Forms 1099-NEC and 4 Forms 1099-MISC must e-file.
When does UK e-invoicing become mandatory? As of October 2026, the government has said mandatory e-invoicing for all VAT invoices will start in 2029. An implementation roadmap was promised for Budget 2026, so check GOV.UK for the latest timetable.
Madras Accountancy supports US businesses and CPA firms with outsourced bookkeeping, AP, month-end close, 1099 preparation and CFO support, working inside the systems your team already uses. To talk through your finance stack and where outside support would help, contact our team.
The section 4960 excise tax is 21% of nonprofit pay over $1M. From 2026 it covers all employees. See the medical carve-outs, Form 4720 and a worked example.
The paid family and medical leave tax credit is permanent from 2026. See the 12.5% to 25% rates, the premium option, the 6-month rule and how Form 8994 works.
Opportunity zones become permanent in 2027 under the One Big Beautiful Bill. See the new deferral, rural bonus, and the 2026 handoff.
