This volume contains 12 thoroughly refereed and revised papers detailing recent advances in research on designing trading agents and mechanisms for agent-mediated e-commerce. They were originally presented at three events: the Workshop on Agent-Mediated Electronic Commerce (AMEC 2013), co-located with AAMAS 2013 in Saint Paul, MN, USA, in May 2013; the Workshop on Trading Agent Design and Analysis (TADA 2013), co-located with AAAI 2013 in Bellevue, WA, USA, in July 2013; and the Joint Workshop on Trading Agent Design and Analysis (TADA 2014) and Agent-Mediated Electronic Commerce (AMEC 2014),...