Capital markets serve as the cornerstone of modern economic systems, facilitating the flow of capital between investors and entities seeking funds for growth and development. This research paper provides a comprehensive examination of capital markets, trading mechanisms, and portfolio management services, exploring their interconnected roles in contemporary financial ecosystems. The study investigates the fundamental structures of capital markets, including primary and secondary markets, and analyzes various financial instruments traded within these platforms, such as equities, bonds, derivatives, and alternative investments. The paper delves into trading systems and methodologies, examining both traditional floor-based trading and modern electronic trading platforms that have revolutionized market accessibility and efficiency. Key trading strategies are evaluated, including day trading, swing trading, algorithmic trading, and high-frequency trading, with particular attention to their risk-return profiles and market impact. The evolution of trading technology and its implications for market liquidity, price discovery, and regulatory frameworks are critically assessed. Portfolio management services represent a crucial component of investment management, encompassing both active and passive management strategies. This research analyzes the theoretical foundations of portfolio management, including Modern Portfolio Theory, Capital Asset Pricing Model, and Efficient Market Hypothesis, while examining their practical applications in wealth management. The study explores various portfolio management approaches, from traditional asset allocation methods to contemporary risk parity and factor-based investing strategies. Furthermore, the paper investigates the role of portfolio managers, investment advisors, and robo-advisors in delivering customized investment solutions to diverse client segments. The integration of environmental, social, and governance factors in portfolio construction is examined as an emerging trend reshaping investment philosophies. Risk management techniques, performance measurement metrics, and the importance of diversification across asset classes and geographical regions are thoroughly analyzed. The research also addresses contemporary challenges facing capital markets, including market volatility, regulatory changes, technological disruption, and geopolitical uncertainties. The impact of financial innovations such as block chain technology, cryptocurrency markets, and artificial intelligence on trading and portfolio management is evaluated. This paper concludes with insights into future trends and the evolving landscape of capital markets and investment management services.