Key Indian stock indices are headed for a weak close today, after having recorded gains in the last two sessions, coming back strongly after some weak spells during the first three sessions last week.A weak close across Asian markets and the downtrend in major European markets amid uncertainty about U.S. President Donald Trump’s trade and economic policies, weigh on sentiment. Although expectations about roll out of the Goods and Services Tax from July 1, 2017 appear to be limiting the market’s downside today, the mood is quite cautious with investors looking ahead to the reporting season that is just a few sessions away. The Sensex is now down 172 points or 0.58% at 29,249.40, around 85 points off the day’s low of 29,163.54. The Nifty50, which declined to 9024.65, is down 55 points or 0.58% at 9053.00.Weakness in Tata Steel (down 3%) and Reliance Industries (down 2.5%) contribute significantly to market’s decline. Coal India, Asian Paints, Wipro, Sun Pharmaceutical Industries, GAIL India, Lupin, ONGC, Tata Motors, Mahindra & Mahindra, Bajaj Auto and Adani Ports are down 1% – 2%.State Bank of India is up 1.4%. HDFC, Power Grid Corporation and Dr Reddy’s Laboratories are modestly higher.