Intellectual Ventures is a company who own the rights to large patent portfolios. Rather than use the patents to, say, make something useful, they sue or threat

Intellectual Ventures is a company who own the rights to large patent portfolios. Rather than use the patents to, say, make something useful, they sue or threaten to sue other companies. For various legal and PR reasons, they file suits using "shell" companies, a company wholly owned by Intellectual Ventures and which exists only or largely on paper. They are exploiting a vulnerability in the system for profit and at the expense of system resources, stability, and usefulness. There's no requirement that a private company disclose all the various names under which it operates, so the only way to list all the shell companies used by this one operation is to correlate thousands of public records held by the Patent Office to see which companies can be linked to Intellectual Ventures.