When entity-X holds 5% or more of company-Y's stock, entity-X has to disclose this in a filing with the SEC. But does company-Y also have to disclose this info via an SEC filing?
It’s the responsibility of the shareholder, not the company, to report a 5%+ equity stake to the SEC.
Institutional holdings are listed over on Yahoo, but the info is only updated infrequently (quarterly). Is there a way to find out more quickly when an entity has taken a 5% stake in a company?