We study a keyword auction model where bidders have constrained budgets. In the absence of budget constraints, Edelman et al. (Am Econ Rev 97(1):242–259, <CitationRef CitationID="CR3">2007</CitationRef>) and Varian (Int J Ind Organ 25(6):1163–1178, <CitationRef CitationID="CR12">2007</CitationRef>) analyze “locally envy-free equilibrium” or “symmetric Nash equilibrium”...</citationref></citationref>