Needlessly convoluted. It would be much simpler to create Numerai as described, and participate oneself, uploading the 'predictions'. The key Numerai person can

Needlessly convoluted. It would be much simpler to create Numerai as described, and participate oneself, uploading the 'predictions'. The key Numerai person can de-anonymize it by looking up the mapping of the 1 stock with insider information, and adding a big buy on that one. (I'm not sure if participants upload their model to be run by Numerai or just provide their predictions based on a public data feed; I think it's the latter, but even if it's the former, you can just create a model optimized to emit a big buy on the key stock and otherwise random & self-canceling.) The rest of the data can (and should be, in case of SEC investigation, as using large-scale real data would generate lots of paper trails like payment to data providers) be genuine and released as described - who knows, the participants might actually find real signals which are profitable and also mask the insider trading.