Abstract: A single advertisement may provide benefits to multiple parties. The results discussed herein show that an ad auctioneer may improve both his own revenue and consumers' welfare by implementing an ad auction that allows cooperation among advertisers in a single ad while maintaining competition between ads. This may be called a “coopetitive” ad auction. An auction system may be configured to implement a coopetitive approach in which bids express complex preferences over ads. In particular, multiple bidders may be allowed to value a single ad, and a single bidder may be allowed to value multiple ads. Accordingly, an advertiser can derive value from clicks on multiple ads.