Whale watching (13F tracking)

Whale watching is tracking what large institutional investors (called "whales") are buying and selling by reading their SEC filings, particularly Form 13F. A 13F is a quarterly report that big money managers must file showing their stock holdings. You encounter this on financial websites and investor forums because these large investors often have sophisticated research teams, so copying their moves can be a shortcut to finding good stocks. However, remember they're playing a different game than you—they have more capital, longer time horizons, and different goals. For example, if you notice a famous hedge fund manager just bought shares of a company you've been researching, it might validate your thesis, but it shouldn't be your only reason to invest.