Financial securities are financial instruments that represent an ownership position, a creditor relationship, or rights to ownership. They can be categorized into two main types: equity securities, such as stocks, which give investors ownership in a company, and debt securities, like bonds, which represent loans made by investors to borrowers. Investors buy financial securities to earn returns, either through price appreciation or interest payments. These instruments are traded on various markets, including stock exchanges and over-the-counter markets, providing liquidity and enabling investors to buy and sell them easily.