Whale watching (13F tracking)

Whale watching is tracking what large institutional investors (called "whales") are buying and selling by reading their required SEC filings, particularly Form 13F. Every quarter, big money managers must publicly disclose their stock holdings, giving retail investors a peek at their playbook. You'll encounter this on financial websites and investor forums where people analyze these filings to spot trends. It matters because these professionals manage billions and often have better research resources than individual investors—following their moves can be educational, though past performance doesn't guarantee future results. For example, if you notice a major fund manager quietly building a position in a company you're researching, it might validate your own analysis or prompt you to dig deeper.