Show ownership and transaction trends over time
While more immediate access to insider filings will alert investors to potential problems sooner, individual transactions by themselves don't give investors the benefit of seeing them within the context of the company's normal transaction and ownership patterns. Without informaiton on historical trends in aggregate, it's impossible for investors to see if insider ownership is increasing or decreasing over time, or to determine if a particular transaction is unusual within the insider's or the company's normal trading activity.

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