I was surprised by the table showing 177,000 listings for one and 700,000 listings in the other.
Ideally they could both share data and mirror each other for both registrations and stolen bike listings, for the most effective use by people who may be unaware of the other entity.
According to this page, project529 uses bikeindex's stolen bike reports in its own listings, but doesn't share its data with bikeindex.
https://bicyclesecurityadvisors.com/protect-your-bike/index-...