IP can be valued using the relief-from-royalty method
One common approach to valuing intellectual property is the relief-from-royalty method under which it is valued as the present value of the royalties that would have been paid, had the IP been licensed in an arm's length transaction. This entails significant judgment respecting the selection of the royalty rate to apply to the cash flows generated by the IP, and the selection of the discount rate to apply to the royalty stream.
[T]here are several "rules of thumb" which can be utilized in determining an appropriate royalty rate. One such rule is the "25 per cent profit split valuation method" which determines a royalty rate in order to allocate 25 per cent of the licensee's profits to the licensor. Although this may serve as a useful starting point to begin consideration of the value of IP, courts have been reluctant to accept this methodology.
Neal Armstrong. Summary of Peter Neelands and Suzy Lendvay, "Valuation of IP based on a royalty stream", The Lawyer's Daily (LexisNexis Canada), January 24, 2018 under General Concepts – FMV – Other.