You could figure out the value of him based on what Sanan sold his interest for. Let's say he owner 25% of him and got $15M for that 25% than the horse would be valued at $60M. Highly unlikey that happened though. I heard it was $10M for 20%, which would make him worth $50M. That is just rumor though. I heard the rumors when he was initially sold in the $2M-$3.5M range. One guy who knows the deal pretty well told me it was $3.5M.

The value of a horse is really whatever an insurance company is willing to insure it for or whatever a purchaser will pay. I am sure if they were willing to pay an insurance company would insure him for $60M. Nobody is going to pay that much for him though if he was sold in full.