Cut through the hype. Track the smart money. Check the evidence.
Explore reported portfolios and ownership changes between quarterly updates—decoded and linked to original SEC filings.Explore reported portfolios and ownership changes between quarterly updates—decoded and linked to original SEC filings.
30 investors · 219,000+ SEC positions · 100+ reporting quarters
Investors worth tracking
Explore their portfolios, recent moves and ownership signals — backed by verified SEC filings.
See important ownership moves before the next 13F cycle.
Quarterly 13F filings show what notable investors held at quarter-end. MarketInsiderLab also tracks verified 13D/13G ownership filings, surfacing major stake changes, threshold crossings and activist signals between 13F cycles.
VERIFIED SEC OWNERSHIP MONITORING · 13D + 13G
From portfolio context to what matters now.
Research what notable investors own, understand important changes, and let MarketInsiderLab monitor the investors and stocks that matter to you.
AAPL22.0%Sold 4.3%
AXP17.1%No change
GOOGL9.4%Bought 45.2%See what they own
See what’s happening now
Get notified when it matters
From raw SEC filing to what it actually means.
MarketInsiderLab turns complex ownership filings into a plain-English explanation — while keeping the original SEC evidence one step away.
Bill Ackman × Seaport Entertainment Group
40.1% reported ownership · Item 4 strategic-transaction language detected
See the relationship, not just the holding.
MarketInsiderLab connects each investor to each stock — showing position history, major changes, portfolio importance and who else owns it.
Apple is Berkshire Hathaway’s #1 reported 13F position at 22.0% of the portfolio.
Major increases, reductions, exits and re-entries are connected to the position timeline.
The coverage behind MarketInsiderLab.
Stock promotions tell one story. The evidence may tell another.
Identify the stock behind investment promotions and check the claims against independent evidence.
Find a promotion we’ve already decoded.
Search by promoter, company, ticker or a recognizable teaser hook. Published Decoders remain free to read and verify.
Stop checking. Start tracking.
Research freely when you want. With Pro, MarketInsiderLab continuously monitors the investors and stocks you care about and alerts you when relevant filings or ownership changes appear.
Track investors
Choose the notable investors that matter to you and turn research intent into continuous monitoring.
Track stocks
Monitor the companies you care about for meaningful activity from notable investors and ownership filers.
Get the signal, not the noise
Personalized monitoring brings relevant investor, stock and ownership events back to you instead of making you repeatedly search for them.
Check the evidence, not just the conclusion.
MarketInsiderLab is built around source-linked SEC evidence, explicit methodology and clear boundaries between reported facts, estimates and interpretation.
Portfolio holdings and ownership events are grounded in the underlying filings.
Filing-based estimates are labeled. Unsupported data is not presented as verified certainty.
We help users investigate evidence without turning it into a trading instruction.