Microsoft Opens Copilot to Partner Plugins for Audit and Tax

Microsoft added 25 finance skills and partner-built plugins to Copilot on October 29, 2026, extending Microsoft Copilot for accountants into audit, tax, compliance and bookkeeping work in Excel and Cowork.

The release follows the first set of finance skills Microsoft introduced in June. The new capabilities are available through the Frontier programme for Copilot in Excel and for Cowork, Microsoft’s tool for long-running, multi-step tasks.

For finance teams and practices already paying for Microsoft 365, Copilot for accountants is a practical change rather than a cosmetic one. Close checklists, reconciliations, audit sampling and tax workpapers can now be started from the tools staff already open every day. The open question is how much of that output survives review, and that is where the detail below matters.

Microsoft said more than 8,000 unique users invoked the accounting skills more than 44,000 times across more than 18,000 Copilot conversations in seven days of limited Insiders availability. The figures do not show how many of those users were professional accountants.

What Microsoft Copilot for accountants now does

The skills fall into five groups. In financial planning and analysis, Copilot can build budget forecasts from actual results and departmental inputs. It can also produce financial statements, reporting packages, disclosures and supporting schedules from source balances.

It compares actual results with budgets, forecasts or prior periods and explains differences by price, volume, mix, rate or timing.

In bookkeeping and close, it organises and tracks month-end, quarter-end and year-end activity, including checklists, task owners, due dates and approvals. It also runs reconciliations across the general ledger, subledgers, bank statements and vendor records. It matches transactions, flags missing records and duplicate entries, and prepares proposed corrections with supporting documentation for review.

In audit, Copilot helps plan and document internal and external engagements. It selects samples, tests controls and traces transactions to source records. It tracks audit requests and records test results, exceptions, findings and evidence. Firms comparing this with dedicated tooling can read Accountio’s explainer on audit data analytics.

In tax, it prepares analyses, supporting calculations and workpapers for planning, compliance and audits. It estimates payments, reconciles tax accounts, tracks filing requirements and picks out issues and due dates in tax notices. Accountio has covered the wider move toward Microsoft Copilot in tax and audit and the basics of AI in tax compliance.

In compliance, it tests accounting controls, reviews adherence to policies and prepares compliance workpapers and regulatory reports. It logs test results and exceptions and tracks corrective actions, owners and due dates.

Which partners built the Copilot plugins

Microsoft listed integrations by category. For accounting, planning and financial management, Copilot connects with Intuit QuickBooks, Xero and Zoho Books. Those three matter most to small practices, because they hold the ledgers that Copilot’s reconciliation and close skills need to read.

For company, credit and risk intelligence, the list names CB Insights, D&B Finance Analytics, D&B Risk Analytics, Daloopa, Fitch Solutions, IBISWorld, Moody’s and Verisk. Investment analysis and wealth management connections are FactSet, Morningstar, Orion, Quartr, Reflexivity, Rogo and Samaya.

Market data and research connections are Fiscal AI, LSEG, MT Newswires, S&P Global, S&P Global Energy, Statista and Zacks. Mercury covers spend management and business banking.

Two Microsoft-built plugins sit alongside them. Microsoft’s Dynamics 365 ERP apps plugin brings finance and operations data and workflows into Copilot, so accountants can prepare journal entries and supporting schedules from the system of record. The Fabric IQ plugin makes governed Microsoft Fabric data usable, starting with Power BI reports and semantic models.

Firms running Microsoft Dynamics 365 Business Central should note that the ERP plugin described by Microsoft covers the finance and operations apps. Check which Dynamics product a client runs before promising anything.

Many of the data connectors were already announced. Microsoft’s June post on Copilot in Excel named CB Insights, Daloopa, FactSet, Morningstar, PitchBook and S&P Global as connectors, and LSEG, Ramp, Rogo, Samaya AI, Velixo and Vena as the first partner wave for skills.

Which tasks move from demo to usable

Tasks with defined inputs and checkable outputs are the strongest candidates. Variance commentary, close tracking and reconciliations all compare numbers that already sit in a ledger or workbook, so a reviewer can verify the result against source.

Journal entry preparation from Dynamics 365 data and drafting follow-up communications for the close are in the same group. The Finance plugin for Cowork pulls close updates together, identifies blockers and risks, investigates variances that need explanation, and drafts commentary for the team to review. It also consolidates budget inputs and prepares a forecast-review brief with spreadsheets, a presentation and follow-up messages.

Audit sampling and tax workpapers are less settled. Copilot can select samples and assemble evidence, but selecting a sample and judging whether the evidence is sufficient are different jobs. Tax notices are a similar case: Copilot identifies issues and due dates, and the adviser decides what they mean for the client.

Accountio’s guide to AI accounting tools by task sets these skills against specialist products in bookkeeping, extraction, close and tax.

Licensing, pricing and data handling

Microsoft’s June post said the core Copilot in Excel features are generally available to Microsoft 365 Copilot customers on web, Windows and Mac. It added that third-party connectors and data providers may require separate licensing or subscriptions from the provider, and that availability, regions and licensing requirements may vary.

That means a Copilot seat does not automatically cover a Moody’s, FactSet or S&P Global feed. Firms should price the data subscription separately before building a workflow around it.

Cowork carries its own conditions. Microsoft’s documentation for the Dynamics 365 ERP plugin says each user needs a Microsoft 365 Copilot licence, an administrator must enable Cowork, and usage-based billing with Copilot Credits must be configured. Details are on Microsoft Learn. Microsoft’s announcement does not publish a per-tier price list for the new skills, so the cost of heavy Cowork use depends on credit consumption.

On data handling, Microsoft’s June post does not describe retention or privacy terms for the skills. It does say workbook rules are stored in the workbook and custom skills are saved as files in OneDrive. Practices handling client data should take the retention and residency questions to their Microsoft account team and tenant administrator before rollout. The Dynamics plugin works within each user’s existing permissions, which is the sensible starting point for access control.

Where human review stays mandatory

Microsoft built review steps into the design. In Excel, professionals can start an audit trail whenever they invoke an accounting capability. If selected, it records in chat history what Copilot changed and why. The June release added a plan option, in which Copilot lists the ranges, worksheets, formulas and assumptions it intends to update before it acts, and a Show Changes pane that attributes edits to Copilot.

The audit and tax skills are described as preparing material “for review”, with assumptions and supporting evidence documented. That wording puts the sign-off with the accountant, and the partner or preparer still owns the opinion, the return and the compliance report.

For practice leaders, the working rules are straightforward. Switch the audit trail on by default. Require a named reviewer for any Copilot-prepared workpaper, reconciliation or tax computation. Keep Copilot out of conclusions on sufficiency of evidence and technical tax positions.

Accountio’s guide to AI agent governance for finance teams sets out where to begin, and the ICAEW and Microsoft AI training programme covers the skills staff need to review this output well.

What comes next for Copilot in finance

Microsoft said in June that custom skills would reach general availability across web, Windows and Mac the following month, and that partner-built skills were slated for the third quarter of 2026. Developers and partners are due to deploy skills through Microsoft Marketplace and the Microsoft 365 Admin Center.

The test for Microsoft Copilot for accountants is whether the 44,000 Insiders invocations turn into firm-wide deployments, and whether the Frontier features reach general availability. Firms piloting now should record error rates on reconciliations and workpapers, because Microsoft has not published accuracy figures for any of the 25 skills.