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Your finance processes deserve better than a business-critical spreadsheet.

Reconciliations, VAT, month-end close, budgets: a large share of finance work still runs through Excel files sitting next to the ERP. JMS designs applications to replace them, with written rules and visible exceptions. AI handles specific tasks, and its suggestions go through human review.

Discuss your process See how it works
VAT_recon_Oct_v7_FINAL(2).xlsx
D4=VLOOKUP(A4,Ledger!A:F,6,FALSE)-C4
  1. importledger and October VAT returnread
  2. ruleT-01 expected VAT by rate and codeapplied
  3. controlT-04 ledger vs return: 2 differenceslisted
  4. AIexplanation suggested for bothsuggestion
  5. review1 difference approved, 1 pendinglogged
  6. exportbridge table and supporting detailready
Illustrative example, fictitious data.

The workbook nobody dares to touch

Most finance teams have one. It was built quickly for a specific need, and it stayed. It feeds a reconciliation, a tax return or a management reporting pack, and only one person really knows how it works.

  1. ERP exports pasted in by hand every monthOne shifted column is enough to distort the result, and nothing flags it.

  2. Nested formulas that nobody reviews any moreThey work as long as the structure of the file never changes.

  3. Business rules that only exist in someone’s headWhen that person is away or leaves, the process stops or degrades.

  4. Checks done by eye, with no recordAfterwards, nobody can say what was checked, or by whom.

  5. A file that drives important decisionsBudgets, pricing and tax returns sometimes rest on it.

An application built around your process

The starting point is the existing file and the people who use it. Implicit rules are written down, agreed with you, then coded. The application follows the steps your team already knows, with controls that run every time the process runs.

Your ERP stays in place

The application works from its exports. CSV or Excel files are often enough to start with. A more direct integration can follow later, if it is worth it.

Rules you can read

Every calculation, matching or control rule is described in plain language and linked to the code that applies it. An auditor or a successor can review it without opening a single formula.

Exceptions in plain sight

Same data, same result. Anything that does not match is listed with its reason and waits for a decision. Corrections leave a trace.

The process can be handed over

Rules and steps are documented in the application. Another team member can take over the process. Getting up to speed still needs planning, but it no longer depends on one person’s memory.

Rules first. AI where it helps.

The applications we design rest on a deterministic core, which calculates, matches and checks according to written rules. AI is added at specific steps when the process calls for it. Its suggestions stay marked as such until an authorised person accepts or rejects them.

On: their suggestions appear dashed and wait for approval.Off: the rules produce the same calculated result, and unusual items are handled by your team without suggestions.

  1. 1input

    Input data

    ERP exports, Excel files, CSV, bank statements, supporting documents, depending on the process.

  2. 2rules

    Deterministic core

    Normalisation, business rules, calculations, matching and controls. Reproducible, and tested against expected results.

  3. 3optionaloff

    AI components

    Reading documents, classifying items, flagging anomalies, drafting an explanation for a variance. Whether they are used depends on the process and your rules.

  4. 4human

    Review and approval

    Suggestions are clearly identified. Corrections and consequential actions remain decisions for authorised people.

  5. 5output

    Traceable output

    Results, exceptions, supporting documents, approvals and exports, with a history of decisions, within the scope of the application.

Illustrative extract from a VAT reconciliation, fictitious data. Switch “AI components” to see what changes.
ControlItemDifferenceTreatment
T-01 Output VAT at 10% 0.00 Calculated and recorded VAT agree (1,240.00)
calculated
T-04 Credit note CN-0312 -362.50
Suggestion: credit note CN-0312 (net 2,500.00) appears to have been posted at 20% instead of 5.5%, which explains the difference
AI · to review
No rule explains the difference: moved to the differences to investigate
pending
T-04 EU supplier invoice F-2209 -873.90 Reverse-charge VAT not recorded, adjusting entry posted
approved by the accountant

Where these files usually live

Six areas where processes around the ERP are common. Each application is built for one specific process, from your files and your rules.

  • Financial reconciliations

    In ExcelManual lookups and differences carried over from one month to the next.

    In the applicationWritten matching rules, exceptions listed and tracked until they are cleared.

  • VAT and tax returns

    In ExcelBridge tables between the ledger and the return, rebuilt every period.

    In the applicationDocumented calculation, systematic consistency checks, supporting detail for every amount reported. The return is still prepared and filed by the company or its accountant.

  • Month-end close

    In ExcelCut-off and provisions calculated in separate tabs.

    In the applicationTracked steps, with evidence attached to each calculation.

  • Budgets and forecasts

    In ExcelMultiple versions and consolidation by copy and paste.

    In the applicationAssumptions in one place, consolidation without rekeying.

  • Supplier and bank flows

    In ExcelStatement imports and invoice checks before payment.

    In the applicationPre-payment checks, exceptions set aside for a decision.

  • Reporting

    In ExcelTables rebuilt every month from several exports.

    In the applicationIndicators recalculated from source, with shared definitions.

This is not a catalogue of off-the-shelf products. The scope of each application is set with you, based on the actual process.

Four steps, in this order

The most useful part of the work happens before the first line of code.

  1. Understand the file

    We go through the real workbook with the people who use it: its rules, its exceptions, the manual fixes, what breaks at month-end.

  2. Write the rules down

    Rules are set out in plain language and agreed with you before they are coded. This is often where inconsistencies in the old file come to light.

  3. Build and compare

    The application is compared with expected results over real periods. Every difference is explained: an error in the application, in the old file, or a rule that needs refining.

  4. Document and hand over

    Rules, technical choices, known limits and the handover procedure are provided in writing. Your IT team knows what it is reviewing and what it is hosting.

What you should be able to examine

A finance application is judged by what can be checked. Each application comes with a file whose contents are agreed with you at the start. Before it goes live, finance and IT should be able to find in it:

  • the business rules, written in plain language and linked to the code that applies them;
  • the test data and the comparison with expected results;
  • the history of versions and fixes;
  • the list of technical components used;
  • the planned hosting, access rights and backups;
  • for each AI component, what it receives, what it suggests and who approves.

Software built the way internal control works

JMS uses AI to develop faster. The code it produces is governed with the logic of an internal control framework:

  • preventivedevelopment, architecture and security rules set before any code is written
  • detectivetests, code analysis and code review
  • correctiveissues documented, fixes logged before release

Limits, stated up front

No application can guarantee zero errors. The aim is that an error can be seen and explained. Hosting, maintenance and support are agreed with you for each application, based on your constraints and those of your IT team.

Jean-Michel Steiger

Qualification
Diplôme d’expertise comptable (DEC), the French national accountancy qualification
Background
KPMG, managing partner of the Praugec accounting firm, managing director of two SMEs
Expertise
Audit, internal control, reporting, SAP, accounting, finance and tax process compliance
Location
Lyon, France. Engagements anywhere, on site or remotely.

Jean-Michel Steiger started at KPMG in Lyon, in statutory audit and on international M&A transactions. He then joined the accounting firm Praugec, where he was managing partner for more than ten years before selling his stake.

From 2020 to 2026 he was managing director of two SMEs, where he built the management tools he could not find: consolidated financial reporting, subcontractor tracking, job scheduling. That is where the method described here took shape.

JMS Accounting & Control brings the two together: corporate finance, and building the tools that keep it running. Jean-Michel Steiger works with a small team.

Jean-Michel Steiger holds the French Diplôme d’expertise comptable. JMS does not carry out engagements reserved for chartered accountants registered with the Ordre des experts-comptables.

Discuss your process

Describe in a few lines the file or process that causes trouble: what it does and who uses it. We will get back to you to arrange a first conversation.

Please do not send files containing confidential data at this stage. If documents are needed, we will agree on a suitable way to share them.

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