Anton and Yao (1989) show that in split-award procurement auctions bidders coordinate their bids to sustain high buyer price. We relax their assumption that the buyer has full information about the suppliers’ production costs and restore the coordination outcome.

In an economy with voluntarily provided public goods and private product varieties, and a general class of CES preferences, it is shown that aggregate public good contribution follows an inverted-U pattern with respect to group size when private and public goods are substitutable in preferences....