LLMs in finance: compare ChatGPT, Claude and Gemini
The right LLM for a finance team passes a reproducible business test in an authorised environment. Compare answer quality, traceability of figures and correction time using the same documents and instructions.
Contents
English version published on 2 October 2026. Sources rechecked on the same date.
Which criteria should you compare across assistants?
ChatGPT, Claude and Gemini differ in more than writing style. Available functions depend on the plan, administrator settings and connected tools. This framework is a selection method, not a benchmark carried out by Iter.
| Criterion | Test | Evidence to retain |
|---|---|---|
| Calculation | Recalculate a table containing credit notes, duplicates and a zero budget | Formulas or code and results reconciled to the answer key |
| Documents | Find five clauses in a document set | File name, page and exact passage |
| Context | Explain a variance whose cause is not supplied | Distinction between fact and hypothesis |
| Integration | Read only authorised folders | Verification of permissions and possible actions |
| Cost | Measure test and correction time | Licences, consumption and review time |
| Environment | Documented starting point | Question to verify |
|---|---|---|
| ChatGPT | File analysis and code-based calculations | Can you verify operations, exclusions and output files? |
| Claude inside a business application | Document analysis in the Hebbia case | Does the chosen application preserve references to supporting documents? |
| Gemini in Data Studio | Assistance with questions, calculated fields and presentations | Are these features available in your plan and data context? |
These examples involve different products and integrations. They do not rank model quality. Compare the configurations actually available to your team.
ChatGPT documents file analysis using calculation tools. Ask every other candidate environment to demonstrate the same task on authorised company data, without assuming equivalent quality.
How do you run a useful comparative test?
- Prepare an authorised file set: variance table, closing procedure and supporting documents.
- Write an answer key with expected figures, sources and unanswered questions.
- Give every tool the same instructions and retain its complete answers.
- Record errors, fabricated references, omissions and correction minutes.
- Repeat sensitive cases: one correct answer does not demonstrate reliability.
An accurate result without a verifiable reference is insufficient for an audit note. Reject an environment if the test requires excessive access rights. The ChatGPT guide exercises offer a reproducible starting point.
What does the Hebbia case show about financial documents?
Anthropic describes Hebbia’s use of Claude to analyse financial and legal documents. Claude runs inside a platform that organises documents and tasks; the application goes beyond an isolated conversation.
For an SME, the lesson to test is documentary traceability. Request a supporting file and passage for every statement. The publisher’s cache-related time reduction must not be interpreted as a finance team’s productivity gain. Read the cases and their scope.
Which decisions must remain subject to human approval?
Budget assumptions, provisions, payment approvals and investor communications commit the company. An assistant can prepare a proposal; retain a named owner and a control trail.
For financial due diligence (FR), use the model to identify missing documents or prepare questions. A model failing to flag a risk does not prove that none exists. The final review also covers what was not supplied.
What should you check before connecting financial data?
Document who can read what, which actions are possible, where data is retained and how access can be revoked. Read OpenAI’s business-data commitments and Anthropic’s training policy for the actual plan selected. Do not transfer a condition from one product to another.
For the pilot, prefer read-only access and a restricted folder. A Fractional CFO can define the business need with IT and data owners. The roadmap connects selection to deployment stages.
Frequently asked questions
Is there a best LLM for every finance department?
No. Selection depends on the file set, available tools, access, expected quality and verification cost. Compare environments on identical tasks.
Can an LLM perform calculations?
An assistant can use code, a spreadsheet or other calculation tools. Verify executed operations and assumptions; a number generated in prose is not evidence of calculation.
How do you measure financial-summary quality?
Compare against an answer key: accurate figures, retrievable sources, no invented causes, material points covered and correction time. Also test information missing from the file set.
Scope your project with a CFO
Share your needs, tools and difficulties. We can clarify the scope, deliverables and controls for support.
Discuss my projectSources & references
- Data analysis with ChatGPT — OpenAI Help Center, source rechecked on 2 October 2026.
- Hebbia: financial-document analysis with Claude — Anthropic / Claude, source rechecked on 2 October 2026.
- Data Studio Pro features (formerly Looker Studio) — Google Cloud, source rechecked on 2 October 2026.
- Business data protection — OpenAI, source rechecked on 2 October 2026.
- Data use for model training — Anthropic Privacy Center, source rechecked on 2 October 2026.