Tata Consultancy Services or TCS today became the first Indian IT company to hit the $100 billion market capitalisation mark, after its shares extended gains to a third straight session. Advances in TCS followed a record quarterly profit reported by the IT major last week and amid weakness in the rupee against the US dollar. TCS also pipped rival Accenture in market capitalisation. The US-listed firm had a market value of $98 billion. TCS shares hit a record high of Rs. 3,557 today. TCS had posted its biggest-ever quarterly profit last week. Mumbai-based TCS, which started trading in 2004, is a unit of Tata Group, one of India's oldest companies that now sells cars, power, tea and chemicals through its various subsidiaries.