Alex Rivera
Breaking News Editor
Breaking News Editor at 13F Insight. First to report on major SEC filings, institutional moves, and regulatory developments.
A note from Alex
Hey, I'm Alex. I spent three and a half years at Bloomberg writing breaking-news pieces about the kind of trades that move tickers in after-hours, and what I learned is that the news cycle moves a lot faster than the explanations do.
That's the gap I'm here to close. When a major insider files a Form 4 at 4:31pm, you should know about it by 5:00 — not in tomorrow's morning newsletter. And you should know what's actually new about it, not just that it happened.
I'll keep my pieces short, my numbers exact, and my opinions out of the lede. If something I wrote ages badly, I'll say so on the record.
Articles by Alex Rivera (827)
- News
Abbott Labs: Capital Research 0.79% MedTech Bet
AI cybersecurity headlines push capital flow scrutiny across all sectors. Abbott Laboratories — the diversified medical-devices, diagnostics, nutrition, and pharma franchise — carries Capital Research Global Investors at $4.07 billion and 0.79% portfolio weight. A medtech-quality concentration thesis.
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Hormuz Cycle: EOG Resources Holders Led by Capital World 1.02%
The Strait of Hormuz tape extends US shale-and-energy exposure. EOG Resources — one of the largest US independent shale producers — carries Capital World Investors at $7.50 billion and 1.02% portfolio weight. The cleanest single-fund active conviction on the US shale franchise economics.
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KKR Holder Read: Capital International 0.76% + Wellington 0.60%
KKR has transformed from a private-equity firm into a diversified alternative-asset platform with public-equity listed shares. The 13F holder book reveals concentrated active conviction at multiple large diversified managers — Capital International at 0.76% portfolio, Wellington at 0.60%, Fidelity at moderate weights.
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April Retail + Deere: Capital World at 0.94% Portfolio Bet
April retail sales acceleration plus the broader rural-economy normalization extends the case for agricultural-equipment recovery. Deere & Company sits at the center of US agricultural-and-construction-equipment economics. Capital World Investors holds DE at $6.91 billion, 0.94% portfolio weight.
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Occidental Hormuz Trade: Berkshire 3.97% + Dodge & Cox 2.65%
Occidental Petroleum sits at the intersection of US shale oil, Permian basin economics, and Berkshire Hathaway's energy thesis. Buffett holds OXY at 3.97% of Berkshire's $274B portfolio. Dodge & Cox holds at 2.65% portfolio. The dual-conviction holder structure anchors OXY institutional positioning.
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Applied Materials: Capital Research Holds AMAT at 1.56% Portfolio
Cisco's AI restructuring extends the semi-capex narrative across the equipment-and-materials supply chain. Applied Materials sits in this category with Capital Research Global Investors at $10.07 billion and 1.56% portfolio weight — the largest single-fund active conviction position on US semi-equipment.
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Humana Holder Read: Dodge & Cox at 1.08% Portfolio Bet
Humana sits at the center of the post-2024 Medicare Advantage repricing cycle. Dodge & Cox — the deep-value institutional manager — holds HUM at $1.97 billion and 1.08% portfolio weight, the largest active overweight in the book. The Dodge & Cox value-discipline call on managed-care.
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Intercontinental Exchange: Harris Associates Runs 3.2% Portfolio
ICE — the parent of NYSE plus a global derivatives, mortgage technology, and fixed-income trading franchise — sits at the center of US market infrastructure. Harris Associates (Oakmark Funds parent) holds $2.52 billion at 3.19% portfolio weight — one of the highest single-fund-family active conviction positions in any exchange operator.
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US Bancorp: MUFG Holds 75.9% of Its US 13F in USB
MUFG Bank Ltd., the US subsidiary of Mitsubishi UFJ Financial Group, holds $2.31 billion in US Bancorp at 75.93% of its reported US 13F portfolio. The position dates to the 2022 MUFG Union Bank divestiture, where MUFG sold its US retail bank to US Bancorp and received USB shares as partial consideration.
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BlackRock Holder Read: Temasek Owns 16.82% of Its 13F in BLK
BlackRock's institutional book carries a singular foreign-strategic-investor concentration: Temasek Holdings of Singapore holds $5.13 billion in BLK at 16.82% of its US 13F portfolio. The position dates to Temasek's strategic investment in BlackRock's growth as a global asset-management platform.
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April Retail Beat: Buffett Owns Amex at 20.46% of His Portfolio
April retail sales beat at +0.5% extends the consumer-discretionary tape. American Express sits in Berkshire Hathaway at $56.09 billion — 20.46% of Berkshire's entire $274 billion portfolio. The 1991 founder position from the Salomon Brothers scandal era is now the second-largest Berkshire holding after Apple.
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John Hess Sells $36M of CVX Post-Merger; 8.58% Beneficial Stake
John Hess — former CEO of Hess Corp, now a major Chevron shareholder following the 2025 merger — sold $36 million of CVX on May 6, 2026 at $183-185 per share. The cumulative Form 4 sell ledger across the merger transition spans $1.37 billion. Schedule 13G/A shows 8.58% beneficial ownership.
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Vertex Pharma: Capital Group Holds $20.7B Across Two 13F Filers
Vertex Pharmaceuticals' institutional book shows Capital World Investors at $11.33 billion (1.55% portfolio) and Capital Research Global Investors at $9.43 billion (1.46% portfolio). Combined Capital Group complex at $20.76 billion makes the firm the largest single-family active conviction on VRTX.
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Coca-Cola: Buffett Holds $28B at 10.2% of Berkshire Portfolio
April retail sales beat at +0.5% extends the consumer-defensive recovery thesis. Coca-Cola is the textbook defensive consumer-staples compounder. Berkshire Hathaway holds KO at $27.96 billion — 10.20% of its portfolio. Warren Buffett has held this position since 1988.
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Mastercard's 96.84% Holder: The Foundation Holding $32.6B in MA
The Mastercard Foundation Asset Management Corp holds $32.60 billion in Mastercard stock — 96.84% of its entire reported 13F portfolio. This is the cleanest charitable-foundation founder-stake concentration in our database. The story is the 2006 Mastercard IPO and the founding gift that created Africa's largest education foundation.
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Pfizer's Active Layer: Fisher Asset Mgmt Holds PFE at 4x Index
Pfizer's 3,136 institutional holders carry a single distinctive active overweight outside the index sleeve: Fisher Asset Management at $2.95 billion, exactly 1.00% portfolio weight — roughly 4x the S&P 500 index weight. Ken Fisher's value-discipline bet on PFE is the conviction signal.
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Healthcare AI Cyber Cycle: Wellington Holds Merck at 3x Index
The cybersecurity news cycle this week extends to healthcare data infrastructure. Merck is one of the largest holders of sensitive pharma R&D data and clinical-trial pipelines. Inside the 3,899-institution holder book, Wellington Management runs MRK at 1.59% portfolio — a 3.5x overweight versus the S&P 500 index weight.
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Intel's Strangest Holder: Nvidia Owns INTC at 60.5% of Its 13F
Nvidia's 13F-HR reports a $7.93 billion Intel position at 60.48% of its entire reported portfolio. That single line — Nvidia owning more than half of its own US 13F book in a direct competitor — is the most unusual single-company-to-competitor stake we've seen in our database. The story behind the number is the 2025 strategic investment.
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Arista CEO Ullal April Trim at $170; Cresset Holds 11.43% Stake
Arista Networks CEO Jayshree Ullal sold approximately $13.5 million of ANET in late April at $167-170. Cumulative $2.2 billion ledger. The conviction layer for ANET sits at Cresset Asset Management — 11.43% portfolio weight in a single name.
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AI Cyber Threat Reshapes UNH Bid: Citadel 1.09%, Wellington 0.91%
Healthcare-data ransomware and AI-enabled phishing against payor systems is one of the costlier sub-segments of the broader cybersecurity threat cycle. UnitedHealth has been the largest single corporate target — the 2024 Change Healthcare breach cost the firm $2+ billion. The 13F holder book carries the institutional positioning that survived the rebuilding.