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)
- Research
Jane Street's $662B Q4 2025 13F: The Secretive Quant Firm Has a Third of Its Portfolio in ETFs
Jane Street Group's latest 13F reveals a $662 billion portfolio where 33% sits in ETFs like SPY and QQQ — a striking allocation from the firm that dominates ETF market-making and just posted a record $10.1 billion trading quarter.
- News
A Microchip Director Sold About $646K After the Company Raised Its Q3 Outlook and Added New Debt
James Eric Bjornholt disclosed three Microchip stock sales worth about $646K across late November and late February as the chipmaker reset guidance and priced fresh convertible notes.
- News
Paycom's Chad Richison Has Kept Selling Stock. The 2026 Story Is Why Context Matters
Paycom founder Chad Richison disclosed a fresh run of stock sales in mid-2025, but the more important question for investors is how those sales line up with Paycom's slower 2026 outlook and the broader payroll software reset.
- News
Motorola Solutions CEO Gregory Brown Has Now Sold Over $1 Billion in MSI Stock — His Latest $13.5M Sale Came After Record Q4
Gregory Brown, Chairman and CEO of Motorola Solutions, sold $13.5 million in MSI shares on March 4-6, 2026, following record Q4 2025 revenue. His career insider sales now exceed $1.09 billion.
- News
$5.1M in UTHR Stock Sold by CEO Martine Rothblatt Days After Phase III Trial Results — A Billion-Dollar Seller Trims Again
United Therapeutics CEO Martine Rothblatt sold $5.1 million in UTHR shares across March 12 and 16, 2026, bringing her career insider sales past $1 billion — just days after the ADVANCE OUTCOMES Phase III results and a Leerink conference appearance.
- 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.
- Research
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.
- News
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.
- News
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.
- News
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.
- News
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.
- News
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.
- News
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.
- News
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.
- Research
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.
- Research
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.
- Research
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.
- Research
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.
- News
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.
- News
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.