Modem Media has been knocked out of the running, with a final decision expected as Revolution went to press.
The account includes online creative and CRM. Due to their shared ownership, the two agencies are not allowed to compete on price.
Monster.com recently hired Mediaedge:cia to handle its £50 million media-planning and buying account.
The agency, also part of WPP, will develop a digital strategy for the pan-European business as part of Monster.com's investment in online advertising.