Shares of Castrol India will remain in focus, as the company on Thursday signed a new strategic partnership with Mahindra & Mahindra. Under the pact, M&M will endorse a range of Castrol products which include aftermarket engine oils and transmission fluids for Mahindra tractors. Based on formulation exclusively developed by M&M for use in its tractors, Castrol will supply these products through its distribution network. Investors will closely monitor the development.