Starbucks (SBUX) rose premarket ahead of Q2 earnings, aiming to snap a 2-day loss. Investors await signs of margin recovery under CEO Brian Niccol after 8 quarters of contraction. SBUX is up 17% YTD. Analysts see $0.44 EPS on $9.09B revenue. Q1 US comp sales grew 4%, the first transaction growth in two years.