Shares of lubricant maker Castrol India, a unit of British Petroleum (BP), surged over 13% after reports of Saudi Arabia's state-owned oil giant Aramco considering taking ownership of BP's Castrol brand. This news comes as BP announced a strategic evaluation of its Castrol division, with a potential valuation of $10 billion, and Aramco showing interest in expanding its presence in key growth markets. The stock price rose for the fourth consecutive session, as the BSE Sensex and NSE Nifty also saw significant gains mid-day.