Sarah Mitchell
Education Editor
Investment Education Editor at 13F Insight. Breaks down complex institutional data into actionable insights for individual investors.
A note from Sarah
Hi, I'm Sarah. I spent four years at Vanguard's Investor Education team, where my whole job was making 401(k) statements feel less like tax forms and more like something a person could actually understand.
I'm here at 13F Insight to do the same thing for institutional data. If you've ever read a headline like "Berkshire Bought Apple" and thought "okay but what does that actually mean for me," that's the gap I want to close.
I'll never assume you know what a CUSIP is. I'll always tell you why a number matters before I give you the number. And if a guide of mine ever leaves you more confused than you started, that's on me — let me know and I'll rewrite it.
Articles by Sarah Mitchell (326)
- News
Lilly Endowment Has Sold $111.8B in LLY Stock — But It's Not a Bearish Signal
The Lilly Endowment, one of America's largest charitable foundations, has systematically sold over $111 billion in Eli Lilly shares since 2003. This is not insider pessimism—it's foundation law in action.
- Learn
How to Spot Insider Buying Signals: A Beginner's Guide to Form 4 Data
Learn how to interpret insider buying transactions on Form 4 filings. Discover what makes a buy meaningful, how to filter noise, and how to use insider trading data to inform your investment decisions.
- Learn
Understanding Portfolio Concentration: When Fewer Holdings Mean More
Learn how institutional investors use portfolio concentration as a strategy, and how to spot concentrated vs. diversified portfolios on 13F Insight.
- Learn
13F Filing Deadlines: When Institutional Holdings Data Is Released
A calendar guide to 13F filing deadlines, amendment windows, and how to plan your institutional holdings research around quarterly filing season for maximum efficiency.
- Learn
How to Use Watchlists to Monitor Smart Money Moves
A step-by-step guide to setting up and using 13F Insight watchlists to track institutional filers and stocks. Learn what to add, how to time your research around filing season, and how to interpret watchlist activity.
- Learn
What Is a Whale Score and How to Use It
A practical guide to using whale scores for screening, comparing, and evaluating institutional 13F filers. Learn when high scores are misleading and how to combine scores with other data for smarter research.
- Learn
How to Track Institutional Buying and Selling With 13F Data
Learn how to use quarter-over-quarter changes in 13F filings to identify when institutional investors are accumulating or distributing positions, and why share count changes matter more than value changes.
- Learn
How to Track Hedge Fund Portfolios Using 13F Data: A Step-by-Step Guide
Want to see what Berkshire Hathaway, Citadel, or Bridgewater is buying? 13F filings let you peek inside hedge fund portfolios every quarter. Here's how to find, read, and interpret the data.
- Learn
What Is a 13D Filing? Understanding Activist Investor Positions
SEC Schedule 13D is required when an investor acquires more than 5% of a company with an intent to influence management. Here's what 13D filings reveal about activist campaigns and why they matter.
- Research
The Big Three Own $15.8 Trillion in Q4 2025: Vanguard, BlackRock, and State Street's Combined 13F Footprint
Vanguard ($6.90T), BlackRock ($5.92T), and State Street ($2.98T) collectively hold $15.8 trillion in 13F-reportable assets across 72,190 positions. Here's how the index fund giants compare.
- Learn
Understanding AUM: What Assets Under Management Really Means
Assets Under Management (AUM) is the total market value of investments managed by a fund or institution. Here's what it means, how it's calculated in 13F filings, and why it matters for investors tracking institutional portfolios.
- Learn
How to Read Form 4 Filings: A Practical Guide to Insider Trading Signals
SEC Form 4 filings reveal when corporate insiders buy, sell, or exercise options in their own company's stock. Here's how to read them and what the patterns actually mean for investors.
- Learn
How to Read a 13F Amendment Without Confusing It for a New Filing
13F amendments restate previous quarter's holdings, not new positions. Learn how amendments work, why they exist, and how 13F Insight handles them so you don't misread the data.
- Learn
ETFs vs Individual Stocks in Institutional Portfolios: What 13F Data Reveals
Some 13F filers are heavy on ETFs, others hold only individual stocks. Learn what the ETF-to-stock ratio tells you about a filer's strategy and how to interpret ETF holdings in institutional data.
- Learn
How to Use Consensus Holdings to Find Institutional Favorites
Consensus holdings show which stocks are owned by the most institutional investors. Learn how to use this tool to identify widely held names and spot emerging institutional favorites.
- Research
Wells Fargo's $549B Q4 2025 Filing Built an ETF Fortress: SPY, IVV, QQQ, and ITOT Control 9.7% of the Book
Wells Fargo's Q4 2025 13F shows $549.1B across 6,616 holdings. Four ETFs (SPY, IVV, QQQ, ITOT) account for $53.8B — a 9.7% allocation to index wrappers that dwarfs the individual stock positions below.
- Learn
How to Spot a Sector Rotation in 13F Data Without Seeing One That Isn't There
Sector rotation — when institutions shift capital between sectors — is one of the most over-claimed signals in 13F analysis. This guide shows how to identify real rotations and avoid false positives.
- Learn
How to Use Stock Detail Pages to Find Who's Buying What — and What the Holder List Actually Shows
Stock detail pages on 13F Insight show which institutions hold a specific stock. This guide explains what the holder list means, how it's ranked, and what it can't tell you.
- Learn
What Voting Authority Fields Mean in a 13F Filing — and Why Most Investors Ignore Them
Every 13F holding reports three voting authority fields: sole, shared, and none. These numbers reveal how much control a filer actually has over the shares they report.
- Learn
How to Read Form 4 Transaction Codes Without Confusing a Gift for a Sale
Form 4 transaction codes (P, S, M, G, A, F, C, J) tell very different stories about insider intent. This guide explains each code and why reading them wrong leads to bad conclusions.