Securities are financial assets that can be traded and represent financial value. There are three main types of securities: debt securities, equity securities, and derivatives. Security analysis involves analyzing various tradable financial instruments to determine their value. It is done through fundamental analysis, technical analysis, and quantitative analysis. Portfolio management aims to select optimal investment plans for clients based on their risk tolerance and return objectives. It involves designing customized portfolios and revising them over time in response to market changes or shifts in client needs.