Markets open in red amid muted global trends: Benchmark indices have opened the session on a flat note tracking mixed global cues after the sharp rebound witnessed on Monday on account of short-covering. At 9.25 AM, the 30-share Sensex is 33 points lower at 27,458 levels and the 50-share Nifty is 17 points down at 8,315. Kotak Mahindra Bank, Dabur India, ABB India, NIIT Technologies and Pfizer are among companies that will announce their respective earnings for the March quarter later during the day. Asian shares are trading cautiously on Tuesday as investors wagered Australia would become the latest country in the region to inject more policy stimulus into its economy. The Indian rupee has opened lower after a long weekend. The currency fell to 63.54 per dollar, down 12 basis points compared to 63.42 a dollar on Thursday. The dollar was slightly firm against a basket of major currencies advancing in thin trade.