An investment bank is typically a private company that provides various financial-related and other services to individuals, corporations, and governments such as raising financial capital by underwriting or acting as the client's agent in the issuance of securities. An investment bank may also assist companies involved in mergers and acquisitions (M&A) and provide ancillary services such as market making, trading of derivatives and equity securities, and FICC services. The two main lines of business in investment banking are called the sell side and the buy side. The "sell side" involves trading securities for cash or for other securities. The "buy side" involves the provision of advice to institutions that buy investment services. Private equity funds, mutual funds, life insurance companies, unit trusts, and hedge funds are the most common types of buy-side entities.