Exercise 9 Formation of patent pools [included in 2nd edition of the book]
Suppose that three firms (noted i= 1;2;3) each own a patent that is essential
to the production of a given final product. For simplicity, we assume that there is
a competitive industry that produces this final product, buying and assembling
the necessary components from each of these three firms. We assume that the
assembly firms incur no other assembly cost in addition to (i) paying royalties
for the use of the three essential patents, (ii) incurring transaction costs when
inquiring about the license fees. Regarding the latter transaction costs, it is
assumed that they are inversely related to the number of different license fees
that are set by the patent holders. Patent holders have indeed the possibility to
form so-called “patent pools” whereby they coordinate their decisions to set a
unique license fee that allows assembly firms to access two (or three, if all firms
join) patents at once. This is modeled as follows.
The price of the final product is denoted by p. Demand for the final
product is given by q=ap.
Competition in the assembly industry therefore ensures that pbe equal to
the the marginal cost of assembly, which depends on the patent pool that
patent holders may have formed. In particular, three options are possible:
p=8
<
:
r1+r2+r3+ 3; if no pool is formed,
rij +rk+ 2; if firms iand jform a pool,
rp+; if the three firms form a pool,
where 0 < a=3is the cost per transaction, riis the license fee set by
firm ifor accessing its patent, rij (resp., rp) is the common fee set by the
pool formed by firms iand j(resp., all firms) for accessing the bundle of
patents iand j(resp., all patents).
1. Suppose that the three patent holders set their license fee independently
and non cooperatively. Derive the Nash equilibrium in fees, compute (i)
the price of the final product (denote it ps) and (ii) the profit of each
patent holder at equilibrium (denote it s).
2. Repeat the previous analysis by assuming that firm iand jcoordinate
their decisions to set a common fee rij that has to be paid for acquiring
the right to use patents iand j. Firm k, on the other hand, still acts
separately and sets its license fee rk. Compute again the price of the
final product (denote it p2), as well as the equilibrium profits of the firms.
Denote the profit of firms iand j in (supposing that they divide their
joint profit equally) and the profit of firm k,out.
3. Suppose now that the three firms form a patent pool and choose a common
license fee rpto maximize their joint profit. Assembly firms that pay rp
have access to the whole set of patents. Derive the optimal rp. Supposing
that the pool’s profit is equally distributed among the three firms, compute
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