Maybe they have settlements with one or two defendants?
"the plaintiff may attempt to use the existence of settlement agreements to the disadvantage of the remaining defendants. For example, if a settlement agreement admits to the validity and infringement of a patent, the plaintiff customarily will want to get that settlement agreement admitted into evidence in the case as proof of non-obviousness. Moreover, if the settlement agreement provides for either a substantial royalty payment or a high royalty rate, the plaintiff invariably will want to rely on that document as evidence of the proper royalty rate to apply in calculating damages from the remaining defendants."