A nanoparticle composition comprising a plurality of stabilized metal-containing nanoparticles comprising silver and/or a silver alloy composite. The stabilized metal-containing nanoparticles are prepared by a method comprising reacting a silver compound with a reducing agent comprising a hydrazine compound by incrementally adding the silver compound to a first mixture comprising the reducing agent, a stabilizer and a solvent. The stabilizer comprises a mixture of a first organoamine and a second organoamine, an alkyl moiety of the first organoamine having a longer carbon chain length than the alkyl moiety of the second organoamine. The first organoamine is selected from the group consisting of decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine and mixtures thereof. The second organoamine is selected from group consisting of butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine and mixtures thereof.