The pool may be held by the licensee, who may be a third party or an association of licensors, or an independent entity (as illustrated by the UNIT AID example in box 11, below). For instance, the holders of different pharmaceutical patents may create among themselves a pool of those patents needed for the production of a new drug, or they may license the patent pool to a generic producer, who would be able to use all the protected materials against the payment of license fees. Depending on the way they are administered and their purpose, patent pools may have pro-competitive, but also anti-competitive effects.