Tata Motors gains as much as 2.76 per cent after a slew of rating upgrades.. As of 10.40 a.m.Tata Motors hares were up 1.6 per cent at Rs 524.60, approaching record high of Rs 531.65 hit on August. 28.. Morgan Stanley upgrades the stock to "overweight" from "equal-weight.". The Bank cites Tata Motor's "attractive" relative valuations and optimism about margins and volumes.. Jefferies also raises its rating on the stock to "buy" from "hold".. Standard and Poor's also raises outlook to "positive" from "stable.". Credit agency cites stronger performance of Tata unit Jaguar Land Rover.. Tata also says on Tuesday it wins order for over 2,700 buses.. Copyright: Thomson Reuters 2014