We experimentally examine the attributes of two complex multi-unit auction mechanisms in the presence of an opportunity to collude among bidding participants due to a provision of a simple communication channel. The results suggest that the combinatorial bidding format does not bring higher...

Using laboratory experiments, we compare the stability of bidding rings in the English auction and the first-price sealed-bid auction in a heterogeneous-value setting. In both a re-matching condition and a fixed-matching condition, we observe that biddings rings are more stable in the English...