Marcus Chen
Senior Market Analyst
Senior Market Analyst at 13F Insight. Covers institutional portfolio strategy, 13F filings, and smart money trends.
A note from Marcus
Hi, I'm Marcus. I spent six years on the buy side staring at 13F filings for a hedge fund, and the thing that bothered me most wasn't the work — it was knowing that the average investor never gets to see what I was looking at, even though it's all public.
That's why I'm here. Every research piece you'll see under my name comes from real SEC data, run through real institutional logic, and translated into something you can actually act on. I write long when the data deserves it and short when it doesn't.
If you ever spot a number that looks off, email me. I'd rather be corrected than wrong.
Articles by Marcus Chen (311)
- Research
Citadel's $666B Q4 2025 Rebalance: Cutting Index Hedges, Adding Alphabet and Semis
Citadel Advisors ended Q4 2025 with a $665.9B 13F portfolio, up 1.33% QoQ, while reducing top-position concentration. The filing shows a clear rebalance: heavier Alphabet and semiconductor exposure, paired with lower SPY/QQQ index hedge weight.
- Research
Thoma Bravo Put 95.4% Into One Stock: Inside the $9.7B SailPoint Concentration in Q4 2025
THOMA BRAVO, L.P. filed a highly concentrated Q4 2025 13F: 95.4% in SailPoint, 99.1% in top two names, and only three reported holdings. We break down what changed from Q3, why MeridianLink disappeared, and how to read sponsor-style filings versus hedge-fund-style filings.
- Research
No Q4 Filing: Burry Ended Scion After Concentrating 96.7% Into PLTR+NVDA Puts
Scion filed no Q4 2025 13F by Feb 19, 2026. Burry's final filing concentrated 96.7% into PLTR/NVDA put exposure, then the fund deregistered seven days later—an extreme final act with unusual conviction and timing.
- Research
Viking Global's Amazon Boomerang: Halvorsen Sold 3.9M Shares in Q3, Bought Them Back in Q4
Viking Global's Q4 2025 13F reveals a portfolio in violent transition: Amazon re-entered after Q3 exit, Meta dumped for Alphabet, banks slashed 60%, and 21 new positions opened. Inside the $37.7B fund's 56% turnover rate.
- Research
Ackman's $1.76B Meta Gambit: Inside Pershing Square's Q4 2025 All-In AI Pivot
Bill Ackman's Pershing Square filed its Q4 2025 13F revealing a brand-new $1.76 billion Meta Platforms position, a 65% Amazon increase, 50% Brookfield accumulation, and a full Chipotle exit — pushing tech exposure to 55% of the $15.5B portfolio.
- Research
Renaissance Slashes NVIDIA 85%, Exits Meta Entirely: Inside the Quant Giant's Most Radical Portfolio Overhaul Since the Quant Quake
Renaissance Technologies' Q4 2025 13F filing reveals the most radical portfolio overhaul in years: an 85% NVIDIA slash, complete Meta exit, 749 positions liquidated, and massive defensive pivots to Costco (+5,221%) and Netflix (+2,545%) — all in the aftermath of October's devastating Quant Quake.
- Research
Bridgewater Associates Q4 2025 13F Deep Dive: The $4.8 Billion SPY Bet and Dalio's Portfolio Transformation
Bridgewater Associates 10x'd their S&P 500 ETF position to $4.8 billion — making SPY 22% of the entire portfolio. Inside the Q4 2024 13F: massive sector rotation, 168 position exits, new Tesla and Robinhood bets, and a consumer defensive retreat that reshaped a $21.8 billion fund.
- Research
Berkshire Hathaway Q4 2025 13F Deep Dive: Inside Buffett's $267 Billion Portfolio
A position-by-position analysis of Berkshire Hathaway's Q4 2024 13F filing. Apple selling stops at 300M shares, BAC reduction continues at -14.7%, Constellation Brands enters as the only new buy, and the top 5 holdings dominate at 72% of the $267B portfolio.
- Research
Whale Fund Filings Decoded: What Buffett, Dalio, Griffin, and Simons Revealed in Q4 2025
The February 14 deadline has passed and every major whale fund has filed. Berkshire stopped selling Apple at 300M shares, Bridgewater made a 10x SPY bet, Renaissance doubled down on Robinhood and Spotify, Ackman added Nike, Viking rotated massively into financials, and Burry went all-in on China. Here is what the data reveals.
- Research
Where Smart Money Converges: The Q4 2025 Institutional Consensus Report
We analyzed 8,541 Q4 2025 13F filings from 8,484 institutional investors to find where smart money converges — and where it diverges. From Microsoft's $264 billion in new institutional capital to the Technology sector's $1.3 trillion dominance, here's what the data reveals about Wall Street's collective positioning heading into 2026.
- News
Q4 2025 13F Filing Season: Renaissance Dumps Meta, Soros Pivots to Amazon as $53 Trillion Wave Hits SEC
The February 14 deadline brought 8,400+ filings from institutional managers totaling $53.3 trillion. Renaissance Technologies and Soros Fund Management reveal dramatic portfolio shifts — while Buffett's Berkshire Hathaway filing remains the most anticipated disclosure still pending.