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 (818)
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Form 4 Cumulative Sell Ledgers: Founder Exit Misread Guide
Joe Mansueto's Form 4 ledger shows $1.95 billion in cumulative Morningstar sales. Charles Schwab's shows $2.87 billion in SCHW sales. Each looks like a founder exit until you read the Schedule 13G/A. Here's how to reconcile the two.
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Gold Royalty Companies in 13F: FNV, OR, RGLD, WPM Explained
Franco-Nevada, Wheaton Precious Metals, Royal Gold, and Osisko Gold Royalties appear in many institutional 13Fs as capital-light precious-metals exposure. Reading them requires understanding royalty/streaming economics — they are not gold miners. Here's the framework.
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Canadian-Mandate Active 13Fs: PineStone, EdgePoint, Mawer
Canadian-domiciled active equity managers run 13F books that look structurally different from US peers. PineStone holds 67.4% in top 10, no Nvidia. EdgePoint runs 21% in Canadian-listed names. Mawer holds dual-listed compounders. Here's why and how to read them.
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Reading Activist 13Fs: Campaign Inventory vs Stock Picks
Carl Icahn's 13F shows 49% in Icahn Enterprises and 21% in CVR Energy. Trian's 13F concentrates in current targets. ValueAct's filings document active engagement positions. Activist 13Fs are structurally different from mainstream active manager filings — they are public campaign inventory, not stock-pick screens.
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Outside-Director Form 4: Why Tim Cook's Nike Trades Show Up
Tim Cook's Form 4 filings include both Apple transactions (as CEO) and Nike transactions (as outside director). Most retail readers miss the second set because they search by company, not by insider. This guide explains how cross-company Form 4 reporting works and why the outside-director purchases are often the most informative signals.
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Founder-Family Trust 13Fs: Hershey, Stryker, Greenleaf
Hershey Trust holds 96.35% of its 13F in Hershey Class B voting stock. Greenleaf Trust holds 51.45% of its 13F in Stryker. Walton Family Holdings concentrates in Walmart. These extreme concentrations are structural — and they reveal a category of 13F that requires different reading rules than mainstream active manager filings.
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Closet Indexing in Active 13Fs: How to Spot It in Top Holdings
Some active managers charge active-management fees while holding portfolios that closely track the S&P 500. The 13F is the cleanest place to see it — and three structural fingerprints reveal closet indexing across nearly every fund family.
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Why P&C Insurance 13Fs Look Different From Asset Managers
State Farm Mutual's top 13F position is Caterpillar at 8.13% portfolio — not Nvidia. Berkshire Hathaway, Allstate, and other property-and-casualty insurance balance sheets file 13Fs that look nothing like mainstream active equity. Here's why, and how to read them.
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How to Read a Quant Fund's 13F: Factor Models in Plain Sight
Renaissance Technologies, Two Sigma, Arrowstreet Capital, Marshall Wace — quantitative equity managers run 13F books that look nothing like discretionary stock-picker filings. Here's how to read what their factor models are telling you, position by position.
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Newport Trust's 12% AT&T Stake Isn't Conviction — Why
Newport Trust Company shows up in the top holders of AT&T at 12.77% of portfolio, Ford at 3.95%, Boeing, Honeywell, and a dozen other legacy industrials. Read those numbers as institutional conviction and you'll misread the entire 13F. Here's what they actually mean.
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Why a TAMP's 13F Looks Different From a Single RIA's
Envestnet's $373B 13F has 4,703 positions and 22.7% top-10 concentration. Creative Planning's $147B 13F has 4,753 positions and 44.9% top-10 concentration. Both are large RIA-adjacent disclosures — but the shape difference says something real.
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How to Read a Sovereign or Foreign Institution's 13F
When the Swiss National Bank or Norges Bank files a 13F showing $174-935 billion in US equities, what does the disclosure actually tell you? Reading these books the same way you'd read an active hedge fund's 13F leads to wrong conclusions.
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Schedule 13D vs 13G: Why the Two-Letter Difference Matters
Two SEC filings cover 5%+ beneficial ownership of US public companies. Schedule 13D and Schedule 13G look almost identical on the cover page. The two-letter difference between them is the most important distinction in the institutional ownership disclosure regime.
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Why an RIA's 13F Looks Different From a Hedge Fund's
A $147B RIA and a $30B hedge fund both file Form 13F-HR. The disclosures look completely different — top holdings, concentration shape, position count, and ticker composition. Knowing why is the difference between using 13F data productively and being misled by surface comparisons.
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How to Read a Cashless Option Exercise on Form 4
When a Form 4 shows both an option exercise (code M) and a same-day sale (code S) at the same accession number, the insider is not 'dumping stock.' This is the cashless exercise pattern — and reading it correctly is the difference between a real signal and a misleading headline.
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PE Sponsor's 13F: A Disposition Schedule, Not a Portfolio
PE sponsors' 13F-HR filings have 5-20 positions, single-name weights of 30-70%, and AUM that can swing 30-50% quarter to quarter. Reading them with active-manager habits is the most common analytical mistake. Here's the right framework.
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Why a $50B Endowment Shows Only $2B on Form 13F
University endowments routinely manage tens of billions of dollars, yet their Form 13F filings often disclose under 5% of that figure. The reason is structural: Form 13F only captures one specific slice of an investment book.
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Why Insurer 13F Tech Concentration Differs From Hedge Funds
When you see Legal & General Group reporting NVDA at 7.23% of its US 13F book, the instinct is to read it as a conviction tilt. The reality is much closer to a cap-weighted index sleeve. This guide explains why insurer 13F concentration looks high but isn't.
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Broker-Dealer 13F vs Active Manager 13F: How to Tell Them Apart
Reading a 13F filing as a list of conviction trades works only when the filer is an active manager. For broker-dealers, custodians, and platform RIAs, the same document is a customer-account aggregate. This guide shows how to tell them apart.
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Reading 10b5-1 Plan Footnotes on Form 4 Filings
When a CEO sells stock, the question is rarely 'how much' — it is 'is this discretionary or pre-arranged?' This guide walks through how to read the Rule 10b5-1 plan footnote on a Form 4 and what it actually changes about the signal.