How to Build Financial Models with Claude Cowork

The "Junior Analyst" in Your Laptop

For the last three years, "AI for Finance" meant pasting text into a chat window and getting a summary back. It was helpful for reading, but useless for building. You couldn't ask ChatGPT to "build a working LBO model" because it couldn't touch your Excel files.

That changed this month with Claude Cowork.

Unlike Microsoft Copilot (which lives inside Excel as a helper), Cowork lives on your desktop. It is an autonomous agent that can read your local folders, process PDFs, and write fully functional.xlsx files with working formulas.

For the Private Equity or IB analyst, this is the shift from "AI as a Research Assistant" to "AI as a Modeler." This guide shows you exactly how to use it.

Prerequisites: Getting Access

Before you start, you need the right setup. Currently, this is a "Research Preview" with strict requirements:

• Hardware: macOS (Windows support is pending as of January 2026).
• Software: Claude Desktop App (latest version).
• Plan: Claude Pro/Max subscription
• Setting: Enable "Cowork" in Settings > Feature Previews.

The Workflow: From "Raw Data" to "Working Model"

Do not treat Cowork like a chatbot. Treat it like a first-year analyst who is incredibly fast but needs clear instructions.

Phase 1: The Setup (The "Virtual Data Room")

Cowork works best when you give it a "Sandbox."

1. Create a Folder: Name it Deal_Project_X on your desktop.
2. Load Context: Drag in your raw data like PDF financial statements, CIMs, expert transcripts or even other excel files.
3. Grant Access: In the Claude Desktop app, click "Cowork" and select this folder. Claude can now "see" everything inside, but nothing else on your computer.

Phase 2: The Ingestion

Manual data scrubbing is dead. Use Cowork to convert unstructured data into structured historicals.

Prompt:

"Review the 'Financials' subfolder containing the last 3 years of 10-Ks. Extract the Income Statement, Balance Sheet, and Cash Flow Statement for each year. Create a new file named Historicals.xlsx. Standardize the line items so they match across years. Hardcode the values in blue."

Phase 3: The Build (The 3-Statement Model)

Now, ask Cowork to build the logic. It understands standard banking formatting and formula linkage.

Prompt:

"Using Historicals.xlsx as the source, create a new file named LBO_Model_v1.xlsx.

1. Assumptions Tab: Create toggles for Revenue Growth (Base/Bear/Bull), EBITDA Margin, and Entry/Exit Multiples.
2. Model Tab: Build a 5-year projection. Link revenue and costs to the Assumptions tab. Ensure the Balance Sheet balances. Calculate Free Cash Flow.
3. Returns Tab: Calculate IRR and MOIC based on a Year 5 exit.
4. Constraint: Use standard financial formatting. All formulas must be dynamic—do not hardcode projections."

The Result: You get a .xlsx file where cell C5 actually equals Assumptions!C5 * (1+Growth). It’s a working shell you can audit and refine.

Claude Cowork vs. Microsoft Copilot: The "Architect" vs. The "Assistant"

They solve different problems. This distinction is best understood by comparing Microsoft Copilot (M365) with Claude Cowork. Copilot is a native "assistant" that lives inside the Excel sidebar; it is useful but constrained, often limited to the active file or specific SharePoint contexts, and prone to struggling with complex nested logic like LAMBDA functions. Cowork, conversely, operates as an OS-level "agent" on your desktop. It possesses a massive context window capable of ingesting entire folders and cross-referencing local files with direct read/write access. While Copilot is designed for chat-based assistance—helping you fix syntax while you work—Cowork is optimized for high-throughput delegation, allowing it to use superior reasoning to build complex models from scratch while you step away.

3 Examples To Get Started

1. The "Comparable Company Analysis" Builder

"I have uploaded 5 competitor 10-Ks in the 'Comps' folder. Create a 'Comps_Table.xlsx'. Extract Revenue, EBITDA, and Net Income for the last fiscal year. Calculate Net Debt based on the Balance Sheets. Leave columns empty for 'Market Cap' and 'Enterprise Value' which I will fill in manually."

2. The "Scenario Manager"

"Open Model_v1.xlsx. Duplicate the 'Projections' tab three times. Rename them 'Base', 'Upside', and 'Downside'. Link the revenue growth assumptions in each tab to the corresponding scenarios in the 'Assumptions' tab. Create a 'Summary' tab that compares EBITDA and IRR across all three cases."

3. The "Sanity Check" (Audit)

"Review Model_v1.xlsx. Check for hardcoded numbers in formula cells. Verify that the Balance Sheet balances in all forecast years. List any potential errors or broken links in a text file named Audit_Log.txt."