10-K → 📈

open10k.com for Investors

Free, clean financial statements for 6,000+ public companies, and how to put AI on top of them

Tim Olsen · Gonzaga University
Student Investing Club · November 11, 2026

A little about me

  • Associate Professor of Management Information Systems, Gonzaga School of Business Administration
  • I teach analytics
  • My research: XBRL (the tagging behind SEC financial data), large language models, semantic modeling, and digital work platforms
  • U.S. Fulbright Scholar in Malaysia, 2021
  • What I'm not: a stock picker. Nothing today is investment advice.
Olsen · open10k.com for Investors · November 2026

Why I built open10k.com

The problem

  • I was asked to teach an accounting analytics course
  • I found the SEC's Financial Statement and Notes data sets: every number in every 10-K, free
  • But seeing a company's trends over 10 years still needed an expensive subscription (Bloomberg, Capital IQ, Compustat)

Why it's hard

  • Each company tags its own numbers in XBRL
  • Even revenue shows up under 194 different tags across 2025 10-Ks
  • Companies switch tags from year to year
  • So I spent two or three years cleaning the data, then used AI to scale it up
The SEC gives this data away. Getting trends out of it shouldn't cost thousands a year.
Olsen · open10k.com for Investors · November 2026

Version 1: just Excel files (August 2026)

One workbook per company, free, no sign-in

  • One column per fiscal year
  • Six tabs: balance sheet, income statement, cash flows, comprehensive income, equity, parenthetical
  • Every figure exactly as reported, not rounded to millions
  • Each year's column links back to the filing on EDGAR
  • A Data (long) tab with the XBRL tag behind every number

Then came built-in checks (August 11)

  • Does the balance sheet balance?
  • Does net income match across statements?
  • Does cash flow tie to the change in cash?

Failed checks are flagged, so you know which numbers to double-check before you build a model on them.

Olsen · open10k.com for Investors · November 2026

Version 2: on the web (open10k.com/AAPL)

Olsen · open10k.com for Investors · November 2026

Version 3: charts (October 2026)

Six charts on most company pages:

  • Income flow (Sankey): where each revenue dollar went
  • Balance sheet: what it owns vs. who has a claim, year by year
  • Cash waterfall: beginning cash to ending cash
  • Sources and uses of cash
  • How the three statements connect
  • Revenue, net income and operating cash flow over time

Hover over any chart for the numbers behind it.

Olsen · open10k.com for Investors · November 2026

What's changed recently

Date What changed
Aug 10 Site goes live: Excel downloads
Aug 11–13 Validity checks in every workbook; links back to EDGAR
Aug 14–18 Statements viewable on the web; full screen; billions, millions or thousands
Sep 29 Segment, geography and product breakdowns, color-coded by whether they add up
Oct 28 Six charts; standardized statements with ratios and the 14 largest industry peers; XBRL tags on hover; Amended 10-Ks report
Nov 5 Annual reports filed in October: Micron (revenue $133.2B, up from $37.4B), Costco, Accenture, AutoZone …

New SEC data arrives monthly, so each month's 10-Ks show up on the site within days. The full list is at open10k.com/updates.

Olsen · open10k.com for Investors · November 2026

Using it to research a stock

1 · The business

Income flow and breakdowns: which segments drive revenue, and where the margin goes

2 · The trend

10+ years in one table: growing revenue? steady margins? operating cash flow keeping up with net income?

3 · The cash

Cash waterfall and sources and uses: funding buybacks and capex, or borrowing to cover a cash burn?

4 · The balance sheet

Leverage and liquidity by year. Negative equity isn't always bad (Altria).

5 · The peers

Standardized statements and ratios beside the 14 largest industry peers

6 · Red flags

Amended 10-Ks, failed tie-out checks, and line items that quietly disappeared

Olsen · open10k.com for Investors · November 2026

Build your own model in Excel

Download the workbook, then:

  • Drop the statements into your DCF or comps template
  • Compute your own ratios: margins, ROIC, FCF conversion, days of inventory
  • Line up 10+ years to build a base case from history, not just the last two years
  • Use the Data (long) tab for a pivot table or Python

Things to know first

  • Figures are as filed, in the reporting currency. A 20-F filer reports in euros or yen, and amber marks it.
  • Annual filings only: 10-K, 20-F, 40-F
  • No stock prices, so bring your own for valuation multiples
  • Restated numbers show the latest reported figure

More at open10k.com/limitations

Olsen · open10k.com for Investors · November 2026

AI

Ask the data in plain English

Connect Claude to every 10-K since 2009

What's an MCP connector?

You“Which software companies grew fastest last year?”
→
Claudewrites a query
→
MCP connectorteton.malloyyo.com
→
SEC dataevery 10-K and 10-Q, 2009–2026
  • MCP (Model Context Protocol) lets Claude use outside tools and data
  • My connector serves a semantic model of the SEC data: about 60 standardized concepts (revenue, net income, assets, cash flows…) for every company and period
  • Claude runs real queries instead of guessing from memory, and every answer comes with a link you can open and check
Olsen · open10k.com for Investors · November 2026

How to add the connector in Claude

  1. Go to claude.ai, then Settings → Connectors
  2. Click Add custom connector
  3. Name: open10k
    URL: https://teton.malloyyo.com/mcp
  4. Click Add, then Connect, and sign in when asked
  5. In a new chat, open the + menu → Connectors and make sure open10k is turned on

Using Claude Code instead?

claude mcp add --transport http \
  open10k https://teton.malloyyo.com/mcp

Custom connectors may depend on your Claude plan. If you can't add one, pair up with someone who can.

Olsen · open10k.com for Investors · November 2026

Try it: questions to ask

Screening

  • “Which companies with over $10B in revenue grew fastest from fiscal 2024 to 2025?”
  • “Show semiconductor companies ranked by operating margin last year.”

Comparing

  • “Compare NVDA, AMD and INTC revenue and net income over the last 10 years.”
  • “How does Costco's cash flow from operations compare with Walmart's?”

Building a dashboard on Malloyyo

  • “Build a dashboard for COST: revenue, margins and free cash flow by year, plus its industry peers.”
  • Claude saves it on teton.malloyyo.com and gives you a link to share

Starting point: the FAC Statement Explorer dashboard is already there: one company's statements, tie-out checks and peers

Olsen · open10k.com for Investors · November 2026

A live answer, and a lesson

“Which companies with ≥ $10B FY2025 revenue grew fastest?”, run through the connector today:

Ticker Company FY2024 FY2025 Growth
CHK Expand Energy $4.2B $12.1B 186%
ROCG Tigo Energy $54.0B $103.5B 92%
OKE ONEOK $21.7B $33.6B 55%
APH Amphenol $15.2B $23.1B 52%
MU Micron $25.1B $37.4B 49%
🚩 Tigo Energy didn’t make $103.5 billion. open10k.com/TYGO shows $103.5 million, a 1,000× difference, and the ticker is stale too. AI makes screening fast, but always click through to the filing before you act on a number.
Olsen · open10k.com for Investors · November 2026
open10k.com

Type any ticker: open10k.com/NVDA · Connector: teton.malloyyo.com/mcp
Found a number that looks wrong? olsent@gonzaga.edu

Olsen · open10k.com for Investors · November 2026

Plan: who I am, why I built this, how it grew from Excel files to charts, how to use it to research a stock, and then we connect Claude to the data.

The 194 tags figure: author's count of distinct tags on the top revenue line of 4,529 10-Ks filed in 2025.

August 14: the same workbook rendered as a web page. Type any ticker after the slash. Later: full screen, billions/millions/thousands, mobile.