"A vote against the proposed amalgamation with Axis is warranted in light of the availability of a superior and relatively certain all-cash offer from a competing bidder," ISS said Friday in its report. Investors have been divided on the proposed Axis merger, which means that proxy advisory firms' recommendations could play a key role in the Aug. 7 vote of PartnerRe shareholders, according to analysts including Amit Kumar of Macquarie Group Ltd. Exor made an unsolicited offer for PartnerRe in April and repeatedly raised its bid, adding a special dividend this week that brought the value to $140.50 a share.