By TheStreet Staff What Is an Investment Bank? An investment bank is very different from your neighborhood bank—it doesn’t make loans, nor does it accept deposits. While investment banks assist individuals with wealth management and provide financial advice to institutions, their main function is to help companies with complex financial transactions, from facilitating mergers and acquisitions to creating initial public offerings (IPOs), guaranteeing securities, insuring bonds, and much more. Investment banks work with everyone from high-net-worth individuals to governments, corporations, pensi…