CEAT rose 2.81% to Rs 1,583.40 after the company announced its plan to acquire an additional 3.47% stake Tyresnmore.CEAT has entered into a third addendum agreement to the existing share subscription and shareholders' agreement with Tyresnmore Online, an associate of the company and other parties, for making a future investment of up to Rs 2.4 crore in Tyresnmore for an additional 3.47% of the post issue total share capital. Upon completion of the investment, the total holding of CEAT in Tyresnmore on a fully diluted basis would be 44.17%. "The proposed investment is by way of subscribing to 12,895 Compulsorily Convertible Preference Shares (CCPS) having face value of Re 1 each to acquire additional 3.47% of the post issue total share capital of Tyresnmore on a fully diluted basis," company said in a regulatory filing on Thursday.