Processes for preparing stabilized metal-containing nanoparticles comprising silver and/or a silver alloy composite by reacting a silver compound with a reducing agent comprising a hydrazine compound at a temperature between about 20° C. and about 60° C. The reaction being carried out by incrementally adding the silver compound or a mixture of the silver compound and a stabilizer to a solution comprising the reducing agent, a stabilizer, and a solvent. Conductive ink compositions containing stabilized metal-containing nanoparticles prepared by such processes.