This study examines the portfolio risk & return by analysing the past data of stock prices and then finding out the optimum weights of the stocks in the portfolio which can yield maximum possible return with the minimum portfolio risk. Here, two similar stocks are taken i.e., ICICI Bank & HDFC Bank. The data analysed are of last five financial years i.e., from 01 April 2017 to 31 March 2022. The stock prices have been adjusted with the relevant corporate action happened in the concerned period. The average of the daily returns, daily risk in form of standard deviation and covariance were used as a measure to analyse the stocks. The study resulted in finding out the optimum weights of the stocks in the portfolio and showed that by intra-sectoral diversification, the risk can be minimised with a sustainable return.