As of the third quarter, 130 hedge funds, private equity groups, family offices and other locally based institutional investors listed more than $285 billion in equity securities of publicly traded companies via the SEC’s 13F-HR form, through which they report holdings that qualify for disclosure. The amounts don’t reflect the full extent of their equity portfolios, which require disclosure only if they exceed a 5 percent stake in a given company. In the case of Bridgewater, for instance, the firm refiled 13F-HR forms on $10.8 billion in equities as of June 30. But the month before, Bridgewater was ranked by...