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 (662)
- Research
Stenger Family Office's Concentrated Tech Strategy: A $484M Deep Dive
Stenger Family Office operates a focused $484M portfolio with 33.9% concentration in top 5 holdings. We analyze the family office's tech-forward conviction strategy and what it signals about institutional capital flows.
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Alpine Global's Concentrated Conviction: IMVT, RIVN, ACHR Mega-Positions
Alpine Global Management's Q4 2025 filing reveals $464M AUM with WhaleScore 80.0, concentrated in three mega-positions (IMVT 14.4%, RIVN 11.2%, ACHR 7.6%) representing 33.2% of portfolio.
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Illumina Founder David Walt Has Sold $114M in ILMN Stock — But He's Still Buying
The Illumina board member and technology founder has unloaded over $114 million in shares while simultaneously accumulating $11.5 million in purchases, a rare pattern that reveals conviction despite recent selling.
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TransDigm Founder Nicholas Howley Has Sold $1.3B in Stock While Building the Aerospace Roll-Up King
The TransDigm Group founder and executive chairman has cashed out over $1.25 billion across 3,515 transactions since 2006, with recent selling continuing through November 2025.
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Phil Knight's $3.1B Nike Selling Spree: How the Co-Founder Became the Company's Biggest Systematic Seller
Nike co-founder Phil Knight has sold $3.1 billion in NKE stock over 13,182 transactions since 2003, making him one of the most prolific insider sellers in corporate history. Recent Form 4 filings show continued conversions and gifts in early 2026.
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Marc Benioff Has Sold $11.4B in Salesforce Stock — The Most Prolific Tech CEO Seller
Salesforce's founder and CEO has executed nearly 29,000 transactions over two decades, making him one of the most aggressive insider sellers in enterprise software. His latest activity: January 2026 option exercises.
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Tesla CFO Vaibhav Taneja Sells $899K in Shares as Stock Hits $398 — Here's What the Timing Signals
Tesla's CFO sold 2,264 shares on March 6 at $397.03 per share, reducing his stake by 11% to 18,106 shares. The sale comes amid mixed Q4 earnings and a stretched valuation.
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Walton Family Holdings Trust Sells $160M in Walmart Stock Over Three Days — Systematic Cadence Continues
The Walton Family Holdings Trust executed 425,962 shares of Walmart across February 23-25, 2026, totaling $159.8M. The pattern reflects ongoing systematic rebalancing, not a bearish signal.
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AMD CEO Lisa Su Sells $28.2M in Shares Through Systematic 10b5-1 Plan
Lisa Su, AMD's Chair, President & CEO, executed a coordinated multi-tranche sale of 128,000 shares on December 10-11, 2025, netting $28.2M. The pattern suggests execution of a pre-arranged 10b5-1 trading plan.
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Renaissance Technologies Q4 2025: The Alphabet Dump, NVIDIA Slash, and What the $64.5M Portfolio Really Tells Us
Renaissance Technologies’ Q4 2025 13F reveals a dramatic Alphabet exit (-89% to -94%), an 85% NVIDIA trim, and a 2,545% NFLX build. But the tiny $64.5M AUM confirms this is NOT the Medallion Fund—here is what the public portfolio actually signals.
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Wellington Management Q4 2025: $571B Giant Makes Bold Bets on DoorDash and Netflix
Wellington Management’s Q4 2025 13F shows aggressive conviction in DoorDash (+593%) and Netflix (+560%), while slashing Boeing and Exact Sciences. Inside the moves of a $571 billion active powerhouse.
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Point72 Q4 2025: Steve Cohen’s $89.4B Fund Makes a $1.56B QQQ Bet While Loading Up on Defensive Plays
Point72 Asset Management’s Q4 2025 13F reveals a $1.56B new QQQ position alongside dramatic increases in UNH (+1,201%), PEP (+965%), and GLD (+891%) — a dual signal of tech conviction and defensive hedging from Steve Cohen’s team.
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Bridgewater’s Q4 2025 Repositioning: A $2.87B IVV Bet and 290 New Positions
Bridgewater Associates doubled its AUM to $27.4B in Q4 2025, anchored by a massive $2.87B iShares S&P 500 ETF position. With 290 new positions and 281 exits, the post-Dalio team is rewriting the playbook.
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Vanguard, BlackRock, and State Street Now Control $15.8 Trillion in U.S. Stocks — Renewing the Passive Ownership Debate
The Big Three's combined Q4 2025 13F holdings reached $15.8 trillion — more than the GDP of Japan and Germany combined. Regulators and academics are increasingly questioning the market impact of passive concentration.
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Q1 2026 13F Filing Season Starts in May: What to Watch After the Tariff Shock and AI Rotation
The Q1 2026 13F filing deadline falls on May 15, 2026. After a volatile Q1 marked by tariff escalation and tech rotation, institutional portfolio changes could be significant. Here's what to watch.
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Saudi Arabia's Public Investment Fund Holds 6.2% of Take-Two Interactive Per 13G Filing — a $3.6 Billion Gaming Bet
Saudi Arabia's Public Investment Fund disclosed a 6.2% stake (11.4M shares) in Take-Two Interactive in a Schedule 13G/A filed December 31, 2025 — continuing the kingdom's aggressive push into gaming.
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Elliott Investment Management Filed a 13D/A on Triple Flag Precious Metals — the Activist Fund's Latest Mining Target
Elliott Investment Management filed a Schedule 13D/A amendment on Triple Flag Precious Metals Corp on December 31, 2025, signaling continued activist engagement with the precious metals streaming company.
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BlackRock's $5.9 Trillion Q4 2025 Filing Has 50,216 Positions — More Than Any Other 13F Filer on Earth
BlackRock's Q4 2025 13F reports $5.92 trillion across a record 50,216 positions. NVDA leads at 6.13%, but the real story is the breadth: 50,000+ line items mapping every corner of U.S. equities.
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The Biggest BlackRock Insider Sale of 2025: Laurence Fink Unloaded $30M in Two Days
BlackRock Chairman and CEO Laurence Fink sold 20,858 shares of BLK stock over July 24-25, 2025, for approximately $30.2 million at prices near $1,125 per share — his largest sale window since selling $44M in August 2022.
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LendingTree Founder Douglas Lebda Holds Just 7,500 Shares While TREE Sits Near Multi-Year Lows
Douglas Lebda, who founded LendingTree and sold $272.8M in career insider transactions, now holds only 7,500 directly-held shares worth roughly $257K as TREE trades near $34 — a fraction of the $70+ levels where his RSUs vested months earlier.