Xlsx Official

# Requirements for Outputs

All Excel files

Zero Formula Errors

- Every Excel model MUST be delivered with ZERO formula errors (#REF!, #DIV/0!, #VALUE!, #N/A, #NAME?)

Preserve Existing Templates (when updating templates)

- Study and EXACTLY match existing format, style, and conventions when modifying files

- Never impose standardized formatting on files with established patterns

- Existing template conventions ALWAYS override these guidelines

Financial models

Color Coding Standards

Unless otherwise stated by the user or existing template

#### Industry-Standard Color Conventions

- **Blue text (RGB: 0,0,255)**: Hardcoded inputs, and numbers users will change for scenarios

- **Black text (RGB: 0,0,0)**: ALL formulas and calculations

- **Green text (RGB: 0,128,0)**: Links pulling from other worksheets within same workbook

- **Red text (RGB: 255,0,0)**: External links to other files

- **Yellow background (RGB: 255,255,0)**: Key assumptions needing attention or cells that need to be updated

Number Formatting Standards

#### Required Format Rules

- **Years**: Format as text strings (e.g., "2024" not "2,024")

- **Currency**: Use $#,##0 format; ALWAYS specify units in headers ("Revenue ($mm)")

- **Zeros**: Use number formatting to make all zeros "-", including percentages (e.g., "$#,##0;($#,##0);-")

- **Percentages**: Default to 0.0% format (one decimal)

- **Multiples**: Format as 0.0x for valuation multiples (EV/EBITDA, P/E)

- **Negative numbers**: Use parentheses (123) not minus -123

Formula Construction Rules

#### Assumptions Placement

- Place ALL assumptions (growth rates, margins, multiples, etc.) in separate assumption cells

- Use cell references instead of hardcoded values in formulas

- Example: Use =B5*(1+$B$6) instead of =B5*1.05

#### Formula Error Prevention

- Verify all cell references are correct

- Check for off-by-one errors in ranges

- Ensure consistent formulas across all projection periods

- Test with edge cases (zero values, negative numbers)

- Verify no unintended circular references

#### Documentation Requirements for Hardcodes

- Comment or in cells beside (if end of table). Format: "Source: [System/Document], [Date], [Specific Reference], [URL if applicable]"

- Examples:

- "Source: Company 10-K, FY2024, Page 45, Revenue Note, [SEC EDGAR URL]"

- "Source: Company 10-Q, Q2 2025, Exhibit 99.1, [SEC EDGAR URL]"

- "Source: Bloomberg Terminal, 8/15/2025, AAPL US Equity"

- "Source: FactSet, 8/20/2025, Consensus Estimates Screen"

# XLSX creation, editing, and analysis

Overview

A user may ask you to create, edit, or analyze the contents of an .xlsx file. You have different tools and workflows available for different tasks.

Important Requirements

**LibreOffice Required for Formula Recalculation**: You can assume LibreOffice is installed for recalculating formula values using the `recalc.py` script. The script automatically configures LibreOffice on first run

Reading and analyzing data

Data analysis with pandas

For data analysis, visualization, and basic operations, use **pandas** which provides powerful data manipulation capabilities:

import pandas as pd

# Read Excel
df = pd.read_excel('file.xlsx')  # Default: first sheet
all_sheets = pd.read_excel('file.xlsx', sheet_name=None)  # All sheets as dict

# Analyze
df.head()      # Preview data
df.info()      # Column info
df.describe()  # Statistics

# Write Excel
df.to_excel('output.xlsx', index=False)

Excel File Workflows

CRITICAL: Use Formulas, Not Hardcoded Values

**Always use Excel formulas instead of calculating values in Python and hardcoding them.** This ensures the spreadsheet remains dynamic and updateable.

❌ WRONG - Hardcoding Calculated Values

# Bad: Calculating in Python and hardcoding result
total = df['Sales'].sum()
sheet['B10'] = total  # Hardcodes 5000

# Bad: Computing growth rate in Python
growth = (df.iloc[-1]['Revenue'] - df.iloc[0]['Revenue']) / df.iloc[0][