8:30a U.S. producer price index unchanged in May 8:30a Core PPI - minus food, energy, trade - falls 0.1% in May 8:30a PPI up 2.4% in past 12 months, core 2.1% 8:31a Gold prices hold modest loss after PPI report 8:31a August gold off $4.40, or 0.4%, at $1,264.50/oz. 8:31a U.S. stock-index futures hold slight gains after data