Citi and Jefferies have given their thumbs up to Oil and Natural Gas Corp. after the government approved 20% premium price for domestic gas produced from new wells. Motilal Oswal Financial Services Ltd. hiked its price target for real estate developer, Signature Global, after strong first quarter results.NDTV Profit tracks what brokerages are putting out on stocks and sectors. Here are all the top calls from analysts you need to know...