manager-portfolio-difflisted

# manager-portfolio-diff You hand over a filer (an alias like "berkshire" or a raw CIK). The skill pulls the two most recent quarterly 13-F filings for that manager, aggregates holdings by CUSIP (handles multi-manager joint filings), and reports the quarter-over-quarter change: initiations, exits, adds, trims, and portfolio value delta. The Massive endpoint doesn't support an issuer-oriented lookup ("who holds AAPL?"), so this is the correct shape for 13-F work: pick the filer whose decisions you want to see and diff their book. ## When to invoke - "What did Berkshire do this quarter?" - "Is Baupost still in that name?" - "Did Pershing Square initiate anything new?" - Any smart-money-following workflow across a curated cohort of funds Not for: "who owns AAPL?" (endpoint doesn't support issuer filter at scale). Not for real-time positioning (13-F is quarterly and lagged ~45 days after quarter-end). ## What you need - Either `--filer` (an alias) OR `--filer-cik` (10-digit CIK) - `MASSIVE_API_KEY` exported - Stocks Basic plan minimum Known aliases: - `berkshire` / `buffett` - `baupost` / `klarman` - `renaissance` / `rentech` - `bridgewater` - `third point` / `loeb` - `pershing` / `pershing square` / `ackman` - `tiger global` / `coleman` - `scion` / `burry` - `appaloosa` / `tepper` For anyone else, look up their CIK at <https://www.sec.gov/cgi-bin/browse-edgar>. ## What you get back Two output layers from one run. **Layer 1: canonical JSON** matching [`output-schema