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 (332)
- Research
Zero Tech in the Top 5: How Dodge & Cox Built a $185B Portfolio That Ignores Silicon Valley
While most institutional giants chase the Magnificent Seven, this 95-year-old value fund puts financials, defense, and healthcare in its top 5 holdings — and its $185B AUM keeps growing.
- Research
Carlyle’s 13F Reveals a $9B Medline Stake and a $4.4B StandardAero Hold: Inside the PE Giant’s 99%-Concentrated Two-Stock Portfolio
Carlyle Group’s Q4 2025 13F shows 99% of its $13.6B portfolio in just two recent IPOs — Medline (healthcare, $9B) and StandardAero (aerospace, $4.4B) — the clearest snapshot of PE-to-public transition in any 13F filing.
- Learn
13F Filing Season Guide: What to Watch and When
13F filing season happens four times a year, 45 days after each quarter ends. Learn the exact deadlines, what to watch for, and how to use 13F Insight to track institutional portfolio changes as they're filed.
- Learn
How to Read Whale Scores: Measuring Institutional Investor Quality
Whale Scores rank institutional investors on a 0-100 scale using three factors: AUM size, portfolio concentration, and filing activity. Learn how to interpret them and find high-conviction money managers.
- Research
SoftBank Sold $6B in NVIDIA to Fund OpenAI and Bet $3.2B on Intel: Inside Masa Son’s $15.5B Q4 2025 AI Infrastructure Pivot
Masayoshi Son exited a $6B NVIDIA position (51% of portfolio) and deployed $10B+ into Intel ($3.2B direct investment), a Bitcoin treasury company ($781M), and Taiwan Semiconductor ($603M) — all to fund a $40B OpenAI commitment. SoftBank’s Q4 2025 13F reveals the most radical portfolio rotation of the filing season.
- Research
ValueAct Deployed $3.9B in One Quarter and Doubled to 16 Holdings: Inside Morfit's $7B Activist Reload With $783M Amazon and a Live Entertainment Empire
ValueAct's 13F portfolio surged from $3.1B to $7.0B in Q4 2025 — a 125% increase in a single quarter. Mason Morfit doubled the firm's positions from 8 to 16, deploying $3.4B into new stakes including Amazon ($783M), BlackRock ($744M), Roblox ($484M), Disney ($350M), and a $564M Live Nation complex across three tickers.
- Research
Gerstner Slashed Broadcom 96% and Dumped Alibaba to Build a $6.7B AI Infrastructure Portfolio: Inside Altimeter's Q4 2025 Conviction Rotation
Brad Gerstner cut Broadcom from $246M to $11M, exited Alibaba entirely, and deployed $2.4B into 8 new positions including Microsoft, Amazon, Snowflake, and CoreWeave — reshaping Altimeter's $6.7B portfolio around an AI infrastructure super cycle thesis.
- Research
Einhorn Is Closing Greenlight to New Money After Gold Delivered 14.5% Alpha: Inside the $2.85B Q4 2025 Portfolio With a 21% Homebuilder Bet
David Einhorn announced Greenlight Capital will close to new investors on July 1, 2026, calling the US equity market 'the most expensive we've seen since we began managing money.' The fund returned 9% in 2025 (vs S&P 500 +17.9%), but macro investments — primarily gold (+64%) and copper (+40%) — contributed 14.5% alpha. The Q4 2025 13F reveals GRBK still dominates at 21%, GPK surged 79%, and Einhorn's net long exposure is just 39%.
- Research
Point72 Bet $1.1B on a Single Biotech While Soros Built a $10.9B Healthcare Empire: How 7 Whale Funds Played the Sector in Q4 2025
Healthcare was the quiet consensus trade of Q4 2025. Point72 put $4.3B (11.3% of its portfolio) into healthcare led by a $1.1B BridgeBio bet. Soros deployed $10.9B across 37 positions. DE Shaw held 31 healthcare names worth $10.9B. But the approaches diverged wildly — from biotech moonshots to managed care defensives. A cross-fund breakdown.
- Research
The AI Chip Divide: Micron Surged 77% in Institutional Holdings While ARM Declined — Q4 2025 Semiconductor Breakdown
Institutional investors added 883 new positions in Micron and 856 in AMD during Q4 2025, but NVIDIA barely grew despite being a $3 trillion position. ARM was the only major semiconductor to lose value. Here's where 5,578 institutions stand on the AI chip trade.
- Research
Point72 Added 880 Holdings and Rebuilt QQQ to $1.56B: Reading the $89B Q4 2025 Reset
Point72's Q4 2025 13F grew to $89.4B with 880 additional holdings, major QQQ rebuild, and lower concentration in the top bucket.
- Research
D. E. Shaw Dropped a $3.81B QQQ Line and Added $3.15B to SPY + AMD While Top-10 Concentration Fell
D.E. Shaw's Q4 2025 13F highlights de-crowding: a $3.81B QQQ line exit offset by larger SPY and AMD allocations, with top-10 concentration declining to 15.97%.