The simultaneous ascending auction has proved to be a successful method of auctioning many related items. Simultaneous sale and ascending bids enable price discovery, which helps bidders build desirable packages of items. Although package bids are not allowed, the auction format does handle mild...

In May 2008, Ofcom’s L-band auction concluded. This was Ofcom’s second combinatorial clock auction. The auction used an innovative format intended to encourage an efficient assignment of the 17 lots. Eight bidders competed for the lots. In sharp contrast to the first combinatorial clock...

In February 2008, Ofcom’s 10-40 GHz auction concluded. This was Ofcom’s first combinatorial clock auction. The auction used an innovative format intended to encourage an efficient assignment of the 27 lots. Each of the ten bidders won one or more lots. All 27 lots were assigned. This note...

I begin by describing some of the problems of the simultaneous ascending auction. Then I present the package clock auction, which retains the benefits, while addressing the weaknesses, of the simultaneous ascending auction. I emphasize two essential elements of the package clock auction: the...